uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

doc/.gitignore

@@ -0,0 +1,8 @@
+*.chapter.xml
+*.section.xml
+.version
+functions/library/generated
+functions/library/locations.xml
+highlightjs
+manual-full.xml
+out

doc/Makefile

@@ -0,0 +1,116 @@
+MD_TARGETS=$(addsuffix .xml, $(basename $(shell find . -type f -regex '.*\.md$$' -not -name README.md)))
+
+PANDOC ?= pandoc
+
+pandoc_media_dir = media
+# NOTE: Keep in sync with NixOS manual (/nixos/doc/manual/md-to-db.sh) and conversion script (/maintainers/scripts/db-to-md.sh).
+# TODO: Remove raw-attribute when we can get rid of DocBook altogether.
+pandoc_commonmark_enabled_extensions = +attributes+fenced_divs+footnotes+bracketed_spans+definition_lists+pipe_tables+raw_attribute
+# Not needed:
+# - docbook-reader/citerefentry-to-rst-role.lua (only relevant for DocBook → MarkDown/rST/MyST)
+pandoc_flags = --extract-media=$(pandoc_media_dir) \
+	--lua-filter=$(PANDOC_LUA_FILTERS_DIR)/diagram-generator.lua \
+	--lua-filter=build-aux/pandoc-filters/myst-reader/roles.lua \
+	--lua-filter=build-aux/pandoc-filters/link-unix-man-references.lua \
+	--lua-filter=build-aux/pandoc-filters/docbook-writer/rst-roles.lua \
+	--lua-filter=build-aux/pandoc-filters/docbook-writer/labelless-link-is-xref.lua \
+	-f commonmark$(pandoc_commonmark_enabled_extensions)+smart
+
+.PHONY: all
+all: validate format out/html/index.html out/epub/manual.epub
+
+.PHONY: debug
+debug:
+	nix-shell --run "xmloscopy --docbook5 ./manual.xml ./manual-full.xml"
+
+.PHONY: format
+format: doc-support/result
+	find . -iname '*.xml' -type f | while read f; do \
+		echo $$f ;\
+		xmlformat --config-file "doc-support/result/xmlformat.conf" -i $$f ;\
+	done
+
+.PHONY: fix-misc-xml
+fix-misc-xml:
+	find . -iname '*.xml' -type f \
+		-exec ../nixos/doc/varlistentry-fixer.rb {} ';'
+
+.PHONY: clean
+clean:
+	rm -f ${MD_TARGETS} doc-support/result .version manual-full.xml functions/library/locations.xml functions/library/generated
+	rm -rf ./out/ ./highlightjs ./media
+
+.PHONY: validate
+validate: manual-full.xml doc-support/result
+	jing doc-support/result/docbook.rng manual-full.xml
+
+out/html/index.html: doc-support/result manual-full.xml style.css highlightjs
+	mkdir -p out/html
+	xsltproc \
+		--nonet --xinclude \
+		--output $@ \
+		doc-support/result/xhtml.xsl \
+		./manual-full.xml
+
+	mkdir -p out/html/highlightjs/
+	cp -r highlightjs out/html/
+
+	cp -r $(pandoc_media_dir) out/html/
+	cp ./overrides.css out/html/
+	cp ./style.css out/html/style.css
+
+	mkdir -p out/html/images/callouts
+	cp doc-support/result/xsl/docbook/images/callouts/*.svg out/html/images/callouts/
+	chmod u+w -R out/html/
+
+out/epub/manual.epub: manual-full.xml
+	mkdir -p out/epub/scratch
+	xsltproc --nonet \
+		--output out/epub/scratch/ \
+		doc-support/result/epub.xsl \
+		./manual-full.xml
+
+	cp -r $(pandoc_media_dir) out/epub/scratch/OEBPS
+	cp ./overrides.css out/epub/scratch/OEBPS
+	cp ./style.css out/epub/scratch/OEBPS
+	mkdir -p out/epub/scratch/OEBPS/images/callouts/
+	cp doc-support/result/xsl/docbook/images/callouts/*.svg out/epub/scratch/OEBPS/images/callouts/
+	echo "application/epub+zip" > mimetype
+	zip -0Xq "out/epub/manual.epub" mimetype
+	rm mimetype
+	cd "out/epub/scratch/" && zip -Xr9D "../manual.epub" *
+	rm -rf "out/epub/scratch/"
+
+highlightjs: doc-support/result
+	mkdir -p highlightjs
+	cp -r doc-support/result/highlightjs/highlight.pack.js highlightjs/
+	cp -r doc-support/result/highlightjs/LICENSE highlightjs/
+	cp -r doc-support/result/highlightjs/mono-blue.css highlightjs/
+	cp -r doc-support/result/highlightjs/loader.js highlightjs/
+
+
+manual-full.xml: ${MD_TARGETS} .version functions/library/locations.xml functions/library/generated *.xml **/*.xml **/**/*.xml
+	xmllint --nonet --xinclude --noxincludenode manual.xml --output manual-full.xml
+
+.version: doc-support/result
+	ln -rfs ./doc-support/result/version .version
+
+doc-support/result: doc-support/default.nix
+	(cd doc-support; nix-build)
+
+functions/library/locations.xml: doc-support/result
+	ln -rfs ./doc-support/result/function-locations.xml functions/library/locations.xml
+
+functions/library/generated: doc-support/result
+	ln -rfs ./doc-support/result/function-docs functions/library/generated
+
+%.section.xml: %.section.md
+	$(PANDOC) $^ -t docbook \
+		$(pandoc_flags) \
+		-o $@
+
+%.chapter.xml: %.chapter.md
+	$(PANDOC) $^ -t docbook \
+		--top-level-division=chapter \
+		$(pandoc_flags) \
+		-o $@

doc/README.md

@@ -0,0 +1,12 @@
+
+# Nixpkgs/doc
+
+This directory houses the sources files for the Nixpkgs manual.
+
+You can find the [rendered documentation for Nixpkgs `unstable` on nixos.org](https://nixos.org/manual/nixpkgs/unstable/).
+
+[Docs for Nixpkgs stable](https://nixos.org/manual/nixpkgs/stable/) are also available.
+
+If you want to contribute to the documentation, [here's how to do it](https://nixos.org/manual/nixpkgs/unstable/#chap-contributing).
+
+If you're only getting started with Nix, go to [nixos.org/learn](https://nixos.org/learn).

doc/build-aux/pandoc-filters/docbook-reader/citerefentry-to-rst-role.lua

@@ -0,0 +1,23 @@
+--[[
+Converts Code AST nodes produced by pandoc’s DocBook reader
+from citerefentry elements into AST for corresponding role
+for reStructuredText.
+
+We use subset of MyST syntax (CommonMark with features from rST)
+so let’s use the rST AST for rST features.
+
+Reference: https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html#role-manpage
+]]
+
+function Code(elem)
+  elem.classes = elem.classes:map(function (x)
+    if x == 'citerefentry' then
+      elem.attributes['role'] = 'manpage'
+      return 'interpreted-text'
+    else
+      return x
+    end
+  end)
+
+  return elem
+end

doc/build-aux/pandoc-filters/docbook-writer/labelless-link-is-xref.lua

@@ -0,0 +1,34 @@
+--[[
+Converts Link AST nodes with empty label to DocBook xref elements.
+
+This is a temporary script to be able use cross-references conveniently
+using syntax taken from MyST, while we still use docbook-xsl
+for generating the documentation.
+
+Reference: https://myst-parser.readthedocs.io/en/latest/using/syntax.html#targets-and-cross-referencing
+]]
+
+local function starts_with(start, str)
+  return str:sub(1, #start) == start
+end
+
+local function escape_xml_arg(arg)
+  amps = arg:gsub('&', '&')
+  amps_quotes = amps:gsub('"', '"')
+  amps_quotes_lt = amps_quotes:gsub('<', '&lt;')
+
+  return amps_quotes_lt
+end
+
+function Link(elem)
+  has_no_content = #elem.content == 0
+  targets_anchor = starts_with('#', elem.target)
+  has_no_attributes = elem.title == '' and elem.identifier == '' and #elem.classes == 0 and #elem.attributes == 0
+
+  if has_no_content and targets_anchor and has_no_attributes then
+    -- xref expects idref without the pound-sign
+    target_without_hash = elem.target:sub(2, #elem.target)
+
+    return pandoc.RawInline('docbook', '<xref linkend="' .. escape_xml_arg(target_without_hash) .. '" />')
+  end
+end

doc/build-aux/pandoc-filters/docbook-writer/rst-roles.lua

@@ -0,0 +1,36 @@
+--[[
+Converts AST for reStructuredText roles into corresponding
+DocBook elements.
+
+Currently, only a subset of roles is supported.
+
+Reference:
+  List of roles:
+    https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html
+  manpage:
+    https://tdg.docbook.org/tdg/5.1/citerefentry.html
+  file:
+    https://tdg.docbook.org/tdg/5.1/filename.html
+]]
+
+function Code(elem)
+  if elem.classes:includes('interpreted-text') then
+    local tag = nil
+    local content = elem.text
+    if elem.attributes['role'] == 'manpage' then
+      tag = 'citerefentry'
+      local title, volnum = content:match('^(.+)%((%w+)%)$')
+      if title == nil then
+        -- No volnum in parentheses.
+        title = content
+      end
+      content = '<refentrytitle>' .. title .. '</refentrytitle>' .. (volnum ~= nil and ('<manvolnum>' .. volnum .. '</manvolnum>') or '')
+    elseif elem.attributes['role'] == 'file' then
+      tag = 'filename'
+    end
+
+    if tag ~= nil then
+      return pandoc.RawInline('docbook', '<' .. tag .. '>' .. content .. '</' .. tag .. '>')
+    end
+  end
+end

doc/build-aux/pandoc-filters/link-unix-man-references.lua

@@ -0,0 +1,17 @@
+--[[
+Turns a manpage reference into a link, when a mapping is defined below.
+]]
+
+local man_urls = {
+  ["tmpfiles.d(5)"] = "https://www.freedesktop.org/software/systemd/man/tmpfiles.d.html",
+  ["nix.conf(5)"] = "https://nixos.org/manual/nix/stable/#sec-conf-file",
+  ["systemd.time(7)"] = "https://www.freedesktop.org/software/systemd/man/systemd.time.html",
+  ["systemd.timer(5)"] = "https://www.freedesktop.org/software/systemd/man/systemd.timer.html",
+}
+
+function Code(elem)
+  local is_man_role = elem.classes:includes('interpreted-text') and elem.attributes['role'] == 'manpage'
+  if is_man_role and man_urls[elem.text] ~= nil then
+    return pandoc.Link(elem, man_urls[elem.text])
+  end
+end

doc/build-aux/pandoc-filters/myst-reader/roles.lua

@@ -0,0 +1,29 @@
+--[[
+Replaces Str AST nodes containing {role}, followed by a Code node
+by a Code node with attrs that would be produced by rST reader
+from the role syntax.
+
+This is to emulate MyST syntax in Pandoc.
+(MyST is a CommonMark flavour with rST features mixed in.)
+
+Reference: https://myst-parser.readthedocs.io/en/latest/syntax/syntax.html#roles-an-in-line-extension-point
+]]
+
+function Inlines(inlines)
+  for i = #inlines-1,1,-1 do
+    local first = inlines[i]
+    local second = inlines[i+1]
+    local correct_tags = first.tag == 'Str' and second.tag == 'Code'
+    if correct_tags then
+      -- docutils supports alphanumeric strings separated by [-._:]
+      -- We are slightly more liberal for simplicity.
+      local role = first.text:match('^{([-._+:%w]+)}$')
+      if role ~= nil then
+        inlines:remove(i)
+        second.attributes['role'] = role
+        second.classes:insert('interpreted-text')
+      end
+    end
+  end
+  return inlines
+end

doc/build-aux/pandoc-filters/myst-writer/roles.lua

@@ -0,0 +1,25 @@
+--[[
+Replaces Code nodes with attrs that would be produced by rST reader
+from the role syntax by a Str AST node containing {role}, followed by a Code node.
+
+This is to emulate MyST syntax in Pandoc.
+(MyST is a CommonMark flavour with rST features mixed in.)
+
+Reference: https://myst-parser.readthedocs.io/en/latest/syntax/syntax.html#roles-an-in-line-extension-point
+]]
+
+function Code(elem)
+  local role = elem.attributes['role']
+
+  if elem.classes:includes('interpreted-text') and role ~= nil then
+    elem.classes = elem.classes:filter(function (c)
+      return c ~= 'interpreted-text'
+    end)
+    elem.attributes['role'] = nil
+
+    return {
+      pandoc.Str('{' .. role .. '}'),
+      elem,
+    }
+  end
+end

doc/builders/fetchers.chapter.md

@@ -0,0 +1,126 @@
+# Fetchers {#chap-pkgs-fetchers}
+
+When using Nix, you will frequently need to download source code and other files from the internet. For this purpose, Nix provides the [_fixed output derivation_](https://nixos.org/manual/nix/stable/#fixed-output-drvs) feature and Nixpkgs provides various functions that implement the actual fetching from various protocols and services.
+
+## Caveats
+
+Because fixed output derivations are _identified_ by their hash, a common mistake is to update a fetcher's URL or a version parameter, without updating the hash. **This will cause the old contents to be used.** So remember to always invalidate the hash argument.
+
+For those who develop and maintain fetchers, a similar problem arises with changes to the implementation of a fetcher. These may cause a fixed output derivation to fail, but won't normally be caught by tests because the supposed output is already in the store or cache. For the purpose of testing, you can use a trick that is embodied by the [`invalidateFetcherByDrvHash`](#tester-invalidateFetcherByDrvHash) function. It uses the derivation `name` to create a unique output path per fetcher implementation, defeating the caching precisely where it would be harmful.
+
+## `fetchurl` and `fetchzip` {#fetchurl}
+
+Two basic fetchers are `fetchurl` and `fetchzip`. Both of these have two required arguments, a URL and a hash. The hash is typically `sha256`, although many more hash algorithms are supported. Nixpkgs contributors are currently recommended to use `sha256`. This hash will be used by Nix to identify your source. A typical usage of `fetchurl` is provided below.
+
+```nix
+{ stdenv, fetchurl }:
+
+stdenv.mkDerivation {
+  name = "hello";
+  src = fetchurl {
+    url = "http://www.example.org/hello.tar.gz";
+    sha256 = "1111111111111111111111111111111111111111111111111111";
+  };
+}
+```
+
+The main difference between `fetchurl` and `fetchzip` is in how they store the contents. `fetchurl` will store the unaltered contents of the URL within the Nix store. `fetchzip` on the other hand, will decompress the archive for you, making files and directories directly accessible in the future. `fetchzip` can only be used with archives. Despite the name, `fetchzip` is not limited to .zip files and can also be used with any tarball.
+
+## `fetchpatch` {#fetchpatch}
+
+`fetchpatch` works very similarly to `fetchurl` with the same arguments expected. It expects patch files as a source and performs normalization on them before computing the checksum. For example, it will remove comments or other unstable parts that are sometimes added by version control systems and can change over time.
+
+- `relative`: Similar to using `git-diff`'s `--relative` flag, only keep changes inside the specified directory, making paths relative to it.
+- `stripLen`: Remove the first `stripLen` components of pathnames in the patch.
+- `extraPrefix`: Prefix pathnames by this string.
+- `excludes`: Exclude files matching these patterns (applies after the above arguments).
+- `includes`: Include only files matching these patterns (applies after the above arguments).
+- `revert`: Revert the patch.
+
+Note that because the checksum is computed after applying these effects, using or modifying these arguments will have no effect unless the `sha256` argument is changed as well.
+
+
+Most other fetchers return a directory rather than a single file.
+
+## `fetchsvn` {#fetchsvn}
+
+Used with Subversion. Expects `url` to a Subversion directory, `rev`, and `sha256`.
+
+## `fetchgit` {#fetchgit}
+
+Used with Git. Expects `url` to a Git repo, `rev`, and `sha256`. `rev` in this case can be full the git commit id (SHA1 hash) or a tag name like `refs/tags/v1.0`.
+
+Additionally, the following optional arguments can be given: `fetchSubmodules = true` makes `fetchgit` also fetch the submodules of a repository. If `deepClone` is set to true, the entire repository is cloned as opposing to just creating a shallow clone. `deepClone = true` also implies `leaveDotGit = true` which means that the `.git` directory of the clone won't be removed after checkout.
+
+If only parts of the repository are needed, `sparseCheckout` can be used. This will prevent git from fetching unnecessary blobs from server, see [git sparse-checkout](https://git-scm.com/docs/git-sparse-checkout) and [git clone --filter](https://git-scm.com/docs/git-clone#Documentation/git-clone.txt---filterltfilter-specgt) for more information:
+
+```nix
+{ stdenv, fetchgit }:
+
+stdenv.mkDerivation {
+  name = "hello";
+  src = fetchgit {
+    url = "https://...";
+    sparseCheckout = ''
+      path/to/be/included
+      another/path
+    '';
+    sha256 = "0000000000000000000000000000000000000000000000000000";
+  };
+}
+```
+
+## `fetchfossil` {#fetchfossil}
+
+Used with Fossil. Expects `url` to a Fossil archive, `rev`, and `sha256`.
+
+## `fetchcvs` {#fetchcvs}
+
+Used with CVS. Expects `cvsRoot`, `tag`, and `sha256`.
+
+## `fetchhg` {#fetchhg}
+
+Used with Mercurial. Expects `url`, `rev`, and `sha256`.
+
+A number of fetcher functions wrap part of `fetchurl` and `fetchzip`. They are mainly convenience functions intended for commonly used destinations of source code in Nixpkgs. These wrapper fetchers are listed below.
+
+## `fetchFromGitea` {#fetchfromgitea}
+
+`fetchFromGitea` expects five arguments. `domain` is the gitea server name. `owner` is a string corresponding to the Gitea user or organization that controls this repository. `repo` corresponds to the name of the software repository. These are located at the top of every Gitea HTML page as `owner`/`repo`. `rev` corresponds to the Git commit hash or tag (e.g `v1.0`) that will be downloaded from Git. Finally, `sha256` corresponds to the hash of the extracted directory. Again, other hash algorithms are also available but `sha256` is currently preferred.
+
+## `fetchFromGitHub` {#fetchfromgithub}
+
+`fetchFromGitHub` expects four arguments. `owner` is a string corresponding to the GitHub user or organization that controls this repository. `repo` corresponds to the name of the software repository. These are located at the top of every GitHub HTML page as `owner`/`repo`. `rev` corresponds to the Git commit hash or tag (e.g `v1.0`) that will be downloaded from Git. Finally, `sha256` corresponds to the hash of the extracted directory. Again, other hash algorithms are also available, but `sha256` is currently preferred.
+
+`fetchFromGitHub` uses `fetchzip` to download the source archive generated by GitHub for the specified revision. If `leaveDotGit`, `deepClone` or `fetchSubmodules` are set to `true`, `fetchFromGitHub` will use `fetchgit` instead. Refer to its section for documentation of these options.
+
+## `fetchFromGitLab` {#fetchfromgitlab}
+
+This is used with GitLab repositories. The arguments expected are very similar to `fetchFromGitHub` above.
+
+## `fetchFromGitiles` {#fetchfromgitiles}
+
+This is used with Gitiles repositories. The arguments expected are similar to `fetchgit`.
+
+## `fetchFromBitbucket` {#fetchfrombitbucket}
+
+This is used with BitBucket repositories. The arguments expected are very similar to fetchFromGitHub above.
+
+## `fetchFromSavannah` {#fetchfromsavannah}
+
+This is used with Savannah repositories. The arguments expected are very similar to `fetchFromGitHub` above.
+
+## `fetchFromRepoOrCz` {#fetchfromrepoorcz}
+
+This is used with repo.or.cz repositories. The arguments expected are very similar to `fetchFromGitHub` above.
+
+## `fetchFromSourcehut` {#fetchfromsourcehut}
+
+This is used with sourcehut repositories. Similar to `fetchFromGitHub` above,
+it expects `owner`, `repo`, `rev` and `sha256`, but don't forget the tilde (~)
+in front of the username! Expected arguments also include `vc` ("git" (default)
+or "hg"), `domain` and `fetchSubmodules`.
+
+If `fetchSubmodules` is `true`, `fetchFromSourcehut` uses `fetchgit`
+or `fetchhg` with `fetchSubmodules` or `fetchSubrepos` set to `true`,
+respectively. Otherwise, the fetcher uses `fetchzip`.

doc/builders/images.xml

@@ -0,0 +1,12 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-images">
+ <title>Images</title>
+ <para>
+  This chapter describes tools for creating various types of images.
+ </para>
+ <xi:include href="images/appimagetools.section.xml" />
+ <xi:include href="images/dockertools.section.xml" />
+ <xi:include href="images/ocitools.section.xml" />
+ <xi:include href="images/snaptools.section.xml" />
+</chapter>

doc/builders/images/appimagetools.section.md

@@ -0,0 +1,48 @@
+# pkgs.appimageTools {#sec-pkgs-appimageTools}
+
+`pkgs.appimageTools` is a set of functions for extracting and wrapping [AppImage](https://appimage.org/) files. They are meant to be used if traditional packaging from source is infeasible, or it would take too long. To quickly run an AppImage file, `pkgs.appimage-run` can be used as well.
+
+::: {.warning}
+The `appimageTools` API is unstable and may be subject to backwards-incompatible changes in the future.
+:::
+
+## AppImage formats {#ssec-pkgs-appimageTools-formats}
+
+There are different formats for AppImages, see [the specification](https://github.com/AppImage/AppImageSpec/blob/74ad9ca2f94bf864a4a0dac1f369dd4f00bd1c28/draft.md#image-format) for details.
+
+- Type 1 images are ISO 9660 files that are also ELF executables.
+- Type 2 images are ELF executables with an appended filesystem.
+
+They can be told apart with `file -k`:
+
+```ShellSession
+$ file -k type1.AppImage
+type1.AppImage: ELF 64-bit LSB executable, x86-64, version 1 (SYSV) ISO 9660 CD-ROM filesystem data 'AppImage' (Lepton 3.x), scale 0-0,
+spot sensor temperature 0.000000, unit celsius, color scheme 0, calibration: offset 0.000000, slope 0.000000, dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=d629f6099d2344ad82818172add1d38c5e11bc6d, stripped\012- data
+
+$ file -k type2.AppImage
+type2.AppImage: ELF 64-bit LSB executable, x86-64, version 1 (SYSV) (Lepton 3.x), scale 232-60668, spot sensor temperature -4.187500, color scheme 15, show scale bar, calibration: offset -0.000000, slope 0.000000 (Lepton 2.x), scale 4111-45000, spot sensor temperature 412442.250000, color scheme 3, minimum point enabled, calibration: offset -75402534979642766821519867692934234112.000000, slope 5815371847733706829839455140374904832.000000, dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.18, BuildID[sha1]=79dcc4e55a61c293c5e19edbd8d65b202842579f, stripped\012- data
+```
+
+Note how the type 1 AppImage is described as an `ISO 9660 CD-ROM filesystem`, and the type 2 AppImage is not.
+
+## Wrapping {#ssec-pkgs-appimageTools-wrapping}
+
+Depending on the type of AppImage you're wrapping, you'll have to use `wrapType1` or `wrapType2`.
+
+```nix
+appimageTools.wrapType2 { # or wrapType1
+  name = "patchwork";
+  src = fetchurl {
+    url = "https://github.com/ssbc/patchwork/releases/download/v3.11.4/Patchwork-3.11.4-linux-x86_64.AppImage";
+    sha256 = "1blsprpkvm0ws9b96gb36f0rbf8f5jgmw4x6dsb1kswr4ysf591s";
+  };
+  extraPkgs = pkgs: with pkgs; [ ];
+}
+```
+
+- `name` specifies the name of the resulting image.
+- `src` specifies the AppImage file to extract.
+- `extraPkgs` allows you to pass a function to include additional packages inside the FHS environment your AppImage is going to run in. There are a few ways to learn which dependencies an application needs:
+  - Looking through the extracted AppImage files, reading its scripts and running `patchelf` and `ldd` on its executables. This can also be done in `appimage-run`, by setting `APPIMAGE_DEBUG_EXEC=bash`.
+  - Running `strace -vfefile` on the wrapped executable, looking for libraries that can't be found.

doc/builders/images/dockertools.section.md

@@ -0,0 +1,314 @@
+# pkgs.dockerTools {#sec-pkgs-dockerTools}
+
+`pkgs.dockerTools` is a set of functions for creating and manipulating Docker images according to the [Docker Image Specification v1.2.0](https://github.com/moby/moby/blob/master/image/spec/v1.2.md#docker-image-specification-v120). Docker itself is not used to perform any of the operations done by these functions.
+
+## buildImage {#ssec-pkgs-dockerTools-buildImage}
+
+This function is analogous to the `docker build` command, in that it can be used to build a Docker-compatible repository tarball containing a single image with one or multiple layers. As such, the result is suitable for being loaded in Docker with `docker load`.
+
+The parameters of `buildImage` with relative example values are described below:
+
+[]{#ex-dockerTools-buildImage}
+[]{#ex-dockerTools-buildImage-runAsRoot}
+
+```nix
+buildImage {
+  name = "redis";
+  tag = "latest";
+
+  fromImage = someBaseImage;
+  fromImageName = null;
+  fromImageTag = "latest";
+
+  contents = pkgs.redis;
+  runAsRoot = ''
+    #!${pkgs.runtimeShell}
+    mkdir -p /data
+  '';
+
+  config = {
+    Cmd = [ "/bin/redis-server" ];
+    WorkingDir = "/data";
+    Volumes = { "/data" = { }; };
+  };
+}
+```
+
+The above example will build a Docker image `redis/latest` from the given base image. Loading and running this image in Docker results in `redis-server` being started automatically.
+
+- `name` specifies the name of the resulting image. This is the only required argument for `buildImage`.
+
+- `tag` specifies the tag of the resulting image. By default it's `null`, which indicates that the nix output hash will be used as tag.
+
+- `fromImage` is the repository tarball containing the base image. It must be a valid Docker image, such as exported by `docker save`. By default it's `null`, which can be seen as equivalent to `FROM scratch` of a `Dockerfile`.
+
+- `fromImageName` can be used to further specify the base image within the repository, in case it contains multiple images. By default it's `null`, in which case `buildImage` will peek the first image available in the repository.
+
+- `fromImageTag` can be used to further specify the tag of the base image within the repository, in case an image contains multiple tags. By default it's `null`, in which case `buildImage` will peek the first tag available for the base image.
+
+- `contents` is a derivation that will be copied in the new layer of the resulting image. This can be similarly seen as `ADD contents/ /` in a `Dockerfile`. By default it's `null`.
+
+- `runAsRoot` is a bash script that will run as root in an environment that overlays the existing layers of the base image with the new resulting layer, including the previously copied `contents` derivation. This can be similarly seen as `RUN ...` in a `Dockerfile`.
+
+> **_NOTE:_** Using this parameter requires the `kvm` device to be available.
+
+- `config` is used to specify the configuration of the containers that will be started off the built image in Docker. The available options are listed in the [Docker Image Specification v1.2.0](https://github.com/moby/moby/blob/master/image/spec/v1.2.md#image-json-field-descriptions).
+
+After the new layer has been created, its closure (to which `contents`, `config` and `runAsRoot` contribute) will be copied in the layer itself. Only new dependencies that are not already in the existing layers will be copied.
+
+At the end of the process, only one new single layer will be produced and added to the resulting image.
+
+The resulting repository will only list the single image `image/tag`. In the case of [the `buildImage` example](#ex-dockerTools-buildImage), it would be `redis/latest`.
+
+It is possible to inspect the arguments with which an image was built using its `buildArgs` attribute.
+
+> **_NOTE:_** If you see errors similar to `getProtocolByName: does not exist (no such protocol name: tcp)` you may need to add `pkgs.iana-etc` to `contents`.
+
+> **_NOTE:_** If you see errors similar to `Error_Protocol ("certificate has unknown CA",True,UnknownCa)` you may need to add `pkgs.cacert` to `contents`.
+
+By default `buildImage` will use a static date of one second past the UNIX Epoch. This allows `buildImage` to produce binary reproducible images. When listing images with `docker images`, the newly created images will be listed like this:
+
+```ShellSession
+$ docker images
+REPOSITORY   TAG      IMAGE ID       CREATED        SIZE
+hello        latest   08c791c7846e   48 years ago   25.2MB
+```
+
+You can break binary reproducibility but have a sorted, meaningful `CREATED` column by setting `created` to `now`.
+
+```nix
+pkgs.dockerTools.buildImage {
+  name = "hello";
+  tag = "latest";
+  created = "now";
+  contents = pkgs.hello;
+
+  config.Cmd = [ "/bin/hello" ];
+}
+```
+
+Now the Docker CLI will display a reasonable date and sort the images as expected:
+
+```ShellSession
+$ docker images
+REPOSITORY   TAG      IMAGE ID       CREATED              SIZE
+hello        latest   de2bf4786de6   About a minute ago   25.2MB
+```
+
+However, the produced images will not be binary reproducible.
+
+## buildLayeredImage {#ssec-pkgs-dockerTools-buildLayeredImage}
+
+Create a Docker image with many of the store paths being on their own layer to improve sharing between images. The image is realized into the Nix store as a gzipped tarball. Depending on the intended usage, many users might prefer to use `streamLayeredImage` instead, which this function uses internally.
+
+`name`
+
+: The name of the resulting image.
+
+`tag` _optional_
+
+: Tag of the generated image.
+
+    *Default:* the output path's hash
+
+`fromImage` _optional_
+
+: The repository tarball containing the base image. It must be a valid Docker image, such as one exported by `docker save`.
+
+    *Default:* `null`, which can be seen as equivalent to `FROM scratch` of a `Dockerfile`.
+
+`contents` _optional_
+
+: Top-level paths in the container. Either a single derivation, or a list of derivations.
+
+    *Default:* `[]`
+
+`config` _optional_
+
+: Run-time configuration of the container. A full list of the options are available at in the [Docker Image Specification v1.2.0](https://github.com/moby/moby/blob/master/image/spec/v1.2.md#image-json-field-descriptions).
+
+    *Default:* `{}`
+
+`created` _optional_
+
+: Date and time the layers were created. Follows the same `now` exception supported by `buildImage`.
+
+    *Default:* `1970-01-01T00:00:01Z`
+
+`maxLayers` _optional_
+
+: Maximum number of layers to create.
+
+    *Default:* `100`
+
+    *Maximum:* `125`
+
+`extraCommands` _optional_
+
+: Shell commands to run while building the final layer, without access to most of the layer contents. Changes to this layer are "on top" of all the other layers, so can create additional directories and files.
+
+`fakeRootCommands` _optional_
+
+: Shell commands to run while creating the archive for the final layer in a fakeroot environment. Unlike `extraCommands`, you can run `chown` to change the owners of the files in the archive, changing fakeroot's state instead of the real filesystem. The latter would require privileges that the build user does not have. Static binaries do not interact with the fakeroot environment. By default all files in the archive will be owned by root.
+
+`enableFakechroot` _optional_
+
+: Whether to run in `fakeRootCommands` in `fakechroot`, making programs behave as though `/` is the root of the image being created, while files in the Nix store are available as usual. This allows scripts that perform installation in `/` to work as expected. Considering that `fakechroot` is implemented via the same mechanism as `fakeroot`, the same caveats apply.
+
+    *Default:* `false`
+
+### Behavior of `contents` in the final image {#dockerTools-buildLayeredImage-arg-contents}
+
+Each path directly listed in `contents` will have a symlink in the root of the image.
+
+For example:
+
+```nix
+pkgs.dockerTools.buildLayeredImage {
+  name = "hello";
+  contents = [ pkgs.hello ];
+}
+```
+
+will create symlinks for all the paths in the `hello` package:
+
+```ShellSession
+/bin/hello -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/bin/hello
+/share/info/hello.info -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/share/info/hello.info
+/share/locale/bg/LC_MESSAGES/hello.mo -> /nix/store/h1zb1padqbbb7jicsvkmrym3r6snphxg-hello-2.10/share/locale/bg/LC_MESSAGES/hello.mo
+```
+
+### Automatic inclusion of `config` references {#dockerTools-buildLayeredImage-arg-config}
+
+The closure of `config` is automatically included in the closure of the final image.
+
+This allows you to make very simple Docker images with very little code. This container will start up and run `hello`:
+
+```nix
+pkgs.dockerTools.buildLayeredImage {
+  name = "hello";
+  config.Cmd = [ "${pkgs.hello}/bin/hello" ];
+}
+```
+
+### Adjusting `maxLayers` {#dockerTools-buildLayeredImage-arg-maxLayers}
+
+Increasing the `maxLayers` increases the number of layers which have a chance to be shared between different images.
+
+Modern Docker installations support up to 128 layers, but older versions support as few as 42.
+
+If the produced image will not be extended by other Docker builds, it is safe to set `maxLayers` to `128`. However, it will be impossible to extend the image further.
+
+The first (`maxLayers-2`) most "popular" paths will have their own individual layers, then layer \#`maxLayers-1` will contain all the remaining "unpopular" paths, and finally layer \#`maxLayers` will contain the Image configuration.
+
+Docker's Layers are not inherently ordered, they are content-addressable and are not explicitly layered until they are composed in to an Image.
+
+## streamLayeredImage {#ssec-pkgs-dockerTools-streamLayeredImage}
+
+Builds a script which, when run, will stream an uncompressed tarball of a Docker image to stdout. The arguments to this function are as for `buildLayeredImage`. This method of constructing an image does not realize the image into the Nix store, so it saves on IO and disk/cache space, particularly with large images.
+
+The image produced by running the output script can be piped directly into `docker load`, to load it into the local docker daemon:
+
+```ShellSession
+$(nix-build) | docker load
+```
+
+Alternatively, the image be piped via `gzip` into `skopeo`, e.g., to copy it into a registry:
+
+```ShellSession
+$(nix-build) | gzip --fast | skopeo copy docker-archive:/dev/stdin docker://some_docker_registry/myimage:tag
+```
+
+## pullImage {#ssec-pkgs-dockerTools-fetchFromRegistry}
+
+This function is analogous to the `docker pull` command, in that it can be used to pull a Docker image from a Docker registry. By default [Docker Hub](https://hub.docker.com/) is used to pull images.
+
+Its parameters are described in the example below:
+
+```nix
+pullImage {
+  imageName = "nixos/nix";
+  imageDigest =
+    "sha256:20d9485b25ecfd89204e843a962c1bd70e9cc6858d65d7f5fadc340246e2116b";
+  finalImageName = "nix";
+  finalImageTag = "1.11";
+  sha256 = "0mqjy3zq2v6rrhizgb9nvhczl87lcfphq9601wcprdika2jz7qh8";
+  os = "linux";
+  arch = "x86_64";
+}
+```
+
+- `imageName` specifies the name of the image to be downloaded, which can also include the registry namespace (e.g. `nixos`). This argument is required.
+
+- `imageDigest` specifies the digest of the image to be downloaded. This argument is required.
+
+- `finalImageName`, if specified, this is the name of the image to be created. Note it is never used to fetch the image since we prefer to rely on the immutable digest ID. By default it's equal to `imageName`.
+
+- `finalImageTag`, if specified, this is the tag of the image to be created. Note it is never used to fetch the image since we prefer to rely on the immutable digest ID. By default it's `latest`.
+
+- `sha256` is the checksum of the whole fetched image. This argument is required.
+
+- `os`, if specified, is the operating system of the fetched image. By default it's `linux`.
+
+- `arch`, if specified, is the cpu architecture of the fetched image. By default it's `x86_64`.
+
+`nix-prefetch-docker` command can be used to get required image parameters:
+
+```ShellSession
+$ nix run nixpkgs.nix-prefetch-docker -c nix-prefetch-docker --image-name mysql --image-tag 5
+```
+
+Since a given `imageName` may transparently refer to a manifest list of images which support multiple architectures and/or operating systems, you can supply the `--os` and `--arch` arguments to specify exactly which image you want. By default it will match the OS and architecture of the host the command is run on.
+
+```ShellSession
+$ nix-prefetch-docker --image-name mysql --image-tag 5 --arch x86_64 --os linux
+```
+
+Desired image name and tag can be set using `--final-image-name` and `--final-image-tag` arguments:
+
+```ShellSession
+$ nix-prefetch-docker --image-name mysql --image-tag 5 --final-image-name eu.gcr.io/my-project/mysql --final-image-tag prod
+```
+
+## exportImage {#ssec-pkgs-dockerTools-exportImage}
+
+This function is analogous to the `docker export` command, in that it can be used to flatten a Docker image that contains multiple layers. It is in fact the result of the merge of all the layers of the image. As such, the result is suitable for being imported in Docker with `docker import`.
+
+> **_NOTE:_** Using this function requires the `kvm` device to be available.
+
+The parameters of `exportImage` are the following:
+
+```nix
+exportImage {
+  fromImage = someLayeredImage;
+  fromImageName = null;
+  fromImageTag = null;
+
+  name = someLayeredImage.name;
+}
+```
+
+The parameters relative to the base image have the same synopsis as described in [buildImage](#ssec-pkgs-dockerTools-buildImage), except that `fromImage` is the only required argument in this case.
+
+The `name` argument is the name of the derivation output, which defaults to `fromImage.name`.
+
+## shadowSetup {#ssec-pkgs-dockerTools-shadowSetup}
+
+This constant string is a helper for setting up the base files for managing users and groups, only if such files don't exist already. It is suitable for being used in a [`buildImage` `runAsRoot`](#ex-dockerTools-buildImage-runAsRoot) script for cases like in the example below:
+
+```nix
+buildImage {
+  name = "shadow-basic";
+
+  runAsRoot = ''
+    #!${pkgs.runtimeShell}
+    ${shadowSetup}
+    groupadd -r redis
+    useradd -r -g redis redis
+    mkdir /data
+    chown redis:redis /data
+  '';
+}
+```
+
+Creating base files like `/etc/passwd` or `/etc/login.defs` is necessary for shadow-utils to manipulate users and groups.

doc/builders/images/ocitools.section.md

@@ -0,0 +1,37 @@
+# pkgs.ociTools {#sec-pkgs-ociTools}
+
+`pkgs.ociTools` is a set of functions for creating containers according to the [OCI container specification v1.0.0](https://github.com/opencontainers/runtime-spec). Beyond that, it makes no assumptions about the container runner you choose to use to run the created container.
+
+## buildContainer {#ssec-pkgs-ociTools-buildContainer}
+
+This function creates a simple OCI container that runs a single command inside of it. An OCI container consists of a `config.json` and a rootfs directory. The nix store of the container will contain all referenced dependencies of the given command.
+
+The parameters of `buildContainer` with an example value are described below:
+
+```nix
+buildContainer {
+  args = [
+    (with pkgs;
+      writeScript "run.sh" ''
+        #!${bash}/bin/bash
+        exec ${bash}/bin/bash
+      '').outPath
+  ];
+
+  mounts = {
+    "/data" = {
+      type = "none";
+      source = "/var/lib/mydata";
+      options = [ "bind" ];
+    };
+  };
+
+  readonly = false;
+}
+```
+
+- `args` specifies a set of arguments to run inside the container. This is the only required argument for `buildContainer`. All referenced packages inside the derivation will be made available inside the container.
+
+- `mounts` specifies additional mount points chosen by the user. By default only a minimal set of necessary filesystems are mounted into the container (e.g procfs, cgroupfs)
+
+- `readonly` makes the container\'s rootfs read-only if it is set to true. The default value is false `false`.

doc/builders/images/snaptools.section.md

@@ -0,0 +1,71 @@
+# pkgs.snapTools {#sec-pkgs-snapTools}
+
+`pkgs.snapTools` is a set of functions for creating Snapcraft images. Snap and Snapcraft is not used to perform these operations.
+
+## The makeSnap Function {#ssec-pkgs-snapTools-makeSnap-signature}
+
+`makeSnap` takes a single named argument, `meta`. This argument mirrors [the upstream `snap.yaml` format](https://docs.snapcraft.io/snap-format) exactly.
+
+The `base` should not be specified, as `makeSnap` will force set it.
+
+Currently, `makeSnap` does not support creating GUI stubs.
+
+## Build a Hello World Snap {#ssec-pkgs-snapTools-build-a-snap-hello}
+
+The following expression packages GNU Hello as a Snapcraft snap.
+
+``` {#ex-snapTools-buildSnap-hello .nix}
+let
+  inherit (import <nixpkgs> { }) snapTools hello;
+in snapTools.makeSnap {
+  meta = {
+    name = "hello";
+    summary = hello.meta.description;
+    description = hello.meta.longDescription;
+    architectures = [ "amd64" ];
+    confinement = "strict";
+    apps.hello.command = "${hello}/bin/hello";
+  };
+}
+```
+
+`nix-build` this expression and install it with `snap install ./result --dangerous`. `hello` will now be the Snapcraft version of the package.
+
+## Build a Graphical Snap {#ssec-pkgs-snapTools-build-a-snap-firefox}
+
+Graphical programs require many more integrations with the host. This example uses Firefox as an example because it is one of the most complicated programs we could package.
+
+``` {#ex-snapTools-buildSnap-firefox .nix}
+let
+  inherit (import <nixpkgs> { }) snapTools firefox;
+in snapTools.makeSnap {
+  meta = {
+    name = "nix-example-firefox";
+    summary = firefox.meta.description;
+    architectures = [ "amd64" ];
+    apps.nix-example-firefox = {
+      command = "${firefox}/bin/firefox";
+      plugs = [
+        "pulseaudio"
+        "camera"
+        "browser-support"
+        "avahi-observe"
+        "cups-control"
+        "desktop"
+        "desktop-legacy"
+        "gsettings"
+        "home"
+        "network"
+        "mount-observe"
+        "removable-media"
+        "x11"
+      ];
+    };
+    confinement = "strict";
+  };
+}
+```
+
+`nix-build` this expression and install it with `snap install ./result --dangerous`. `nix-example-firefox` will now be the Snapcraft version of the Firefox package.
+
+The specific meaning behind plugs can be looked up in the [Snapcraft interface documentation](https://docs.snapcraft.io/supported-interfaces).

doc/builders/packages/cataclysm-dda.section.md

@@ -0,0 +1,129 @@
+# Cataclysm: Dark Days Ahead {#cataclysm-dark-days-ahead}
+
+## How to install Cataclysm DDA {#how-to-install-cataclysm-dda}
+
+To install the latest stable release of Cataclysm DDA to your profile, execute
+`nix-env -f "<nixpkgs>" -iA cataclysm-dda`. For the curses build (build
+without tiles), install `cataclysmDDA.stable.curses`. Note: `cataclysm-dda` is
+an alias to `cataclysmDDA.stable.tiles`.
+
+If you like access to a development build of your favorite git revision,
+override `cataclysm-dda-git` (or `cataclysmDDA.git.curses` if you like curses
+build):
+
+```nix
+cataclysm-dda-git.override {
+  version = "YYYY-MM-DD";
+  rev = "YOUR_FAVORITE_REVISION";
+  sha256 = "CHECKSUM_OF_THE_REVISION";
+}
+```
+
+The sha256 checksum can be obtained by
+
+```sh
+nix-prefetch-url --unpack "https://github.com/CleverRaven/Cataclysm-DDA/archive/${YOUR_FAVORITE_REVISION}.tar.gz"
+```
+
+The default configuration directory is `~/.cataclysm-dda`. If you prefer
+`$XDG_CONFIG_HOME/cataclysm-dda`, override the derivation:
+
+```nix
+cataclysm-dda.override {
+  useXdgDir = true;
+}
+```
+
+## Important note for overriding packages {#important-note-for-overriding-packages}
+
+After applying `overrideAttrs`, you need to fix `passthru.pkgs` and
+`passthru.withMods` attributes either manually or by using `attachPkgs`:
+
+```nix
+let
+  # You enabled parallel building.
+  myCDDA = cataclysm-dda-git.overrideAttrs (_: {
+    enableParallelBuilding = true;
+  });
+
+  # Unfortunately, this refers to the package before overriding and
+  # parallel building is still disabled.
+  badExample = myCDDA.withMods (_: []);
+
+  inherit (cataclysmDDA) attachPkgs pkgs wrapCDDA;
+
+  # You can fix it by hand
+  goodExample1 = myCDDA.overrideAttrs (old: {
+    passthru = old.passthru // {
+      pkgs = pkgs.override { build = goodExample1; };
+      withMods = wrapCDDA goodExample1;
+    };
+  });
+
+  # or by using a helper function `attachPkgs`.
+  goodExample2 = attachPkgs pkgs myCDDA;
+in
+
+# badExample                     # parallel building disabled
+# goodExample1.withMods (_: [])  # parallel building enabled
+goodExample2.withMods (_: [])    # parallel building enabled
+```
+
+## Customizing with mods {#customizing-with-mods}
+
+To install Cataclysm DDA with mods of your choice, you can use `withMods`
+attribute:
+
+```nix
+cataclysm-dda.withMods (mods: with mods; [
+  tileset.UndeadPeople
+])
+```
+
+All mods, soundpacks, and tilesets available in nixpkgs are found in
+`cataclysmDDA.pkgs`.
+
+Here is an example to modify existing mods and/or add more mods not available
+in nixpkgs:
+
+```nix
+let
+  customMods = self: super: lib.recursiveUpdate super {
+    # Modify existing mod
+    tileset.UndeadPeople = super.tileset.UndeadPeople.overrideAttrs (old: {
+      # If you like to apply a patch to the tileset for example
+      patches = [ ./path/to/your.patch ];
+    });
+
+    # Add another mod
+    mod.Awesome = cataclysmDDA.buildMod {
+      modName = "Awesome";
+      version = "0.x";
+      src = fetchFromGitHub {
+        owner = "Someone";
+        repo = "AwesomeMod";
+        rev = "...";
+        sha256 = "...";
+      };
+      # Path to be installed in the unpacked source (default: ".")
+      modRoot = "contents/under/this/path/will/be/installed";
+    };
+
+    # Add another soundpack
+    soundpack.Fantastic = cataclysmDDA.buildSoundPack {
+      # ditto
+    };
+
+    # Add another tileset
+    tileset.SuperDuper = cataclysmDDA.buildTileSet {
+      # ditto
+    };
+  };
+in
+cataclysm-dda.withMods (mods: with mods.extend customMods; [
+  tileset.UndeadPeople
+  mod.Awesome
+  soundpack.Fantastic
+  tileset.SuperDuper
+])
+```

doc/builders/packages/citrix.section.md

@@ -0,0 +1,32 @@
+# Citrix Workspace {#sec-citrix}
+
+The [Citrix Workspace App](https://www.citrix.com/products/workspace-app/) is a remote desktop viewer which provides access to [XenDesktop](https://www.citrix.com/products/xenapp-xendesktop/) installations.
+
+## Basic usage {#sec-citrix-base}
+
+The tarball archive needs to be downloaded manually, as the license agreements of the vendor for [Citrix Workspace](https://www.citrix.de/downloads/workspace-app/linux/workspace-app-for-linux-latest.html) needs to be accepted first. Then run `nix-prefetch-url file://$PWD/linuxx64-$version.tar.gz`. With the archive available in the store, the package can be built and installed with Nix.
+
+## Citrix Self-service {#sec-citrix-selfservice}
+
+The [self-service](https://support.citrix.com/article/CTX200337) is an application managing Citrix desktops and applications. Please note that this feature only works with at least citrix_workspace_20_06_0 and later versions.
+
+In order to set this up, you first have to [download the `.cr` file from the Netscaler Gateway](https://its.uiowa.edu/support/article/102186). After that, you can configure the `selfservice` like this:
+
+```ShellSession
+$ storebrowse -C ~/Downloads/receiverconfig.cr
+$ selfservice
+```
+
+## Custom certificates {#sec-citrix-custom-certs}
+
+The `Citrix Workspace App` in `nixpkgs` trusts several certificates [from the Mozilla database](https://curl.haxx.se/docs/caextract.html) by default. However, several companies using Citrix might require their own corporate certificate. On distros with imperative packaging, these certs can be stored easily in [`$ICAROOT`](https://developer-docs.citrix.com/projects/receiver-for-linux-command-reference/en/13.7/), however this directory is a store path in `nixpkgs`. In order to work around this issue, the package provides a simple mechanism to add custom certificates without rebuilding the entire package using `symlinkJoin`:
+
+```nix
+with import <nixpkgs> { config.allowUnfree = true; };
+let
+  extraCerts = [
+    ./custom-cert-1.pem
+    ./custom-cert-2.pem # ...
+  ];
+in citrix_workspace.override { inherit extraCerts; }
+```

doc/builders/packages/dlib.section.md

@@ -0,0 +1,13 @@
+# DLib {#dlib}
+
+[DLib](http://dlib.net/) is a modern, C++-based toolkit which provides several machine learning algorithms.
+
+## Compiling without AVX support {#compiling-without-avx-support}
+
+Especially older CPUs don\'t support [AVX](https://en.wikipedia.org/wiki/Advanced_Vector_Extensions) (Advanced Vector Extensions) instructions that are used by DLib to optimize their algorithms.
+
+On the affected hardware errors like `Illegal instruction` will occur. In those cases AVX support needs to be disabled:
+
+```nix
+self: super: { dlib = super.dlib.override { avxSupport = false; }; }
+```

doc/builders/packages/eclipse.section.md

@@ -0,0 +1,64 @@
+# Eclipse {#sec-eclipse}
+
+The Nix expressions related to the Eclipse platform and IDE are in [`pkgs/applications/editors/eclipse`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/eclipse).
+
+Nixpkgs provides a number of packages that will install Eclipse in its various forms. These range from the bare-bones Eclipse Platform to the more fully featured Eclipse SDK or Scala-IDE packages and multiple version are often available. It is possible to list available Eclipse packages by issuing the command:
+
+```ShellSession
+$ nix-env -f '<nixpkgs>' -qaP -A eclipses --description
+```
+
+Once an Eclipse variant is installed, it can be run using the `eclipse` command, as expected. From within Eclipse, it is then possible to install plugins in the usual manner by either manually specifying an Eclipse update site or by installing the Marketplace Client plugin and using it to discover and install other plugins. This installation method provides an Eclipse installation that closely resemble a manually installed Eclipse.
+
+If you prefer to install plugins in a more declarative manner, then Nixpkgs also offer a number of Eclipse plugins that can be installed in an _Eclipse environment_. This type of environment is created using the function `eclipseWithPlugins` found inside the `nixpkgs.eclipses` attribute set. This function takes as argument `{ eclipse, plugins ? [], jvmArgs ? [] }` where `eclipse` is a one of the Eclipse packages described above, `plugins` is a list of plugin derivations, and `jvmArgs` is a list of arguments given to the JVM running the Eclipse. For example, say you wish to install the latest Eclipse Platform with the popular Eclipse Color Theme plugin and also allow Eclipse to use more RAM. You could then add:
+
+```nix
+packageOverrides = pkgs: {
+  myEclipse = with pkgs.eclipses; eclipseWithPlugins {
+    eclipse = eclipse-platform;
+    jvmArgs = [ "-Xmx2048m" ];
+    plugins = [ plugins.color-theme ];
+  };
+}
+```
+
+to your Nixpkgs configuration (`~/.config/nixpkgs/config.nix`) and install it by running `nix-env -f '<nixpkgs>' -iA myEclipse` and afterward run Eclipse as usual. It is possible to find out which plugins are available for installation using `eclipseWithPlugins` by running:
+
+```ShellSession
+$ nix-env -f '<nixpkgs>' -qaP -A eclipses.plugins --description
+```
+
+If there is a need to install plugins that are not available in Nixpkgs then it may be possible to define these plugins outside Nixpkgs using the `buildEclipseUpdateSite` and `buildEclipsePlugin` functions found in the `nixpkgs.eclipses.plugins` attribute set. Use the `buildEclipseUpdateSite` function to install a plugin distributed as an Eclipse update site. This function takes `{ name, src }` as argument, where `src` indicates the Eclipse update site archive. All Eclipse features and plugins within the downloaded update site will be installed. When an update site archive is not available, then the `buildEclipsePlugin` function can be used to install a plugin that consists of a pair of feature and plugin JARs. This function takes an argument `{ name, srcFeature, srcPlugin }` where `srcFeature` and `srcPlugin` are the feature and plugin JARs, respectively.
+
+Expanding the previous example with two plugins using the above functions, we have:
+
+```nix
+packageOverrides = pkgs: {
+  myEclipse = with pkgs.eclipses; eclipseWithPlugins {
+    eclipse = eclipse-platform;
+    jvmArgs = [ "-Xmx2048m" ];
+    plugins = [
+      plugins.color-theme
+      (plugins.buildEclipsePlugin {
+        name = "myplugin1-1.0";
+        srcFeature = fetchurl {
+          url = "http://…/features/myplugin1.jar";
+          sha256 = "123…";
+        };
+        srcPlugin = fetchurl {
+          url = "http://…/plugins/myplugin1.jar";
+          sha256 = "123…";
+        };
+      });
+      (plugins.buildEclipseUpdateSite {
+        name = "myplugin2-1.0";
+        src = fetchurl {
+          stripRoot = false;
+          url = "http://…/myplugin2.zip";
+          sha256 = "123…";
+        };
+      });
+    ];
+  };
+}
+```

doc/builders/packages/elm.section.md

@@ -0,0 +1,11 @@
+# Elm {#sec-elm}
+
+To start a development environment, run:
+
+```ShellSession
+nix-shell -p elmPackages.elm elmPackages.elm-format
+```
+
+To update the Elm compiler, see `nixpkgs/pkgs/development/compilers/elm/README.md`.
+
+To package Elm applications, [read about elm2nix](https://github.com/hercules-ci/elm2nix#elm2nix).

doc/builders/packages/emacs.section.md

@@ -0,0 +1,119 @@
+# Emacs {#sec-emacs}
+
+## Configuring Emacs {#sec-emacs-config}
+
+The Emacs package comes with some extra helpers to make it easier to configure. `emacs.pkgs.withPackages` allows you to manage packages from ELPA. This means that you will not have to install that packages from within Emacs. For instance, if you wanted to use `company` `counsel`, `flycheck`, `ivy`, `magit`, `projectile`, and `use-package` you could use this as a `~/.config/nixpkgs/config.nix` override:
+
+```nix
+{
+  packageOverrides = pkgs: with pkgs; {
+    myEmacs = emacs.pkgs.withPackages (epkgs: (with epkgs.melpaStablePackages; [
+      company
+      counsel
+      flycheck
+      ivy
+      magit
+      projectile
+      use-package
+    ]));
+  }
+}
+```
+
+You can install it like any other packages via `nix-env -iA myEmacs`. However, this will only install those packages. It will not `configure` them for us. To do this, we need to provide a configuration file. Luckily, it is possible to do this from within Nix! By modifying the above example, we can make Emacs load a custom config file. The key is to create a package that provides a `default.el` file in `/share/emacs/site-start/`. Emacs knows to load this file automatically when it starts.
+
+```nix
+{
+  packageOverrides = pkgs: with pkgs; rec {
+    myEmacsConfig = writeText "default.el" ''
+      ;; initialize package
+
+      (require 'package)
+      (package-initialize 'noactivate)
+      (eval-when-compile
+        (require 'use-package))
+
+      ;; load some packages
+
+      (use-package company
+        :bind ("<C-tab>" . company-complete)
+        :diminish company-mode
+        :commands (company-mode global-company-mode)
+        :defer 1
+        :config
+        (global-company-mode))
+
+      (use-package counsel
+        :commands (counsel-descbinds)
+        :bind (([remap execute-extended-command] . counsel-M-x)
+               ("C-x C-f" . counsel-find-file)
+               ("C-c g" . counsel-git)
+               ("C-c j" . counsel-git-grep)
+               ("C-c k" . counsel-ag)
+               ("C-x l" . counsel-locate)
+               ("M-y" . counsel-yank-pop)))
+
+      (use-package flycheck
+        :defer 2
+        :config (global-flycheck-mode))
+
+      (use-package ivy
+        :defer 1
+        :bind (("C-c C-r" . ivy-resume)
+               ("C-x C-b" . ivy-switch-buffer)
+               :map ivy-minibuffer-map
+               ("C-j" . ivy-call))
+        :diminish ivy-mode
+        :commands ivy-mode
+        :config
+        (ivy-mode 1))
+
+      (use-package magit
+        :defer
+        :if (executable-find "git")
+        :bind (("C-x g" . magit-status)
+               ("C-x G" . magit-dispatch-popup))
+        :init
+        (setq magit-completing-read-function 'ivy-completing-read))
+
+      (use-package projectile
+        :commands projectile-mode
+        :bind-keymap ("C-c p" . projectile-command-map)
+        :defer 5
+        :config
+        (projectile-global-mode))
+    '';
+
+    myEmacs = emacs.pkgs.withPackages (epkgs: (with epkgs.melpaStablePackages; [
+      (runCommand "default.el" {} ''
+         mkdir -p $out/share/emacs/site-lisp
+         cp ${myEmacsConfig} $out/share/emacs/site-lisp/default.el
+       '')
+      company
+      counsel
+      flycheck
+      ivy
+      magit
+      projectile
+      use-package
+    ]));
+  };
+}
+```
+
+This provides a fairly full Emacs start file. It will load in addition to the user's personal config. You can always disable it by passing `-q` to the Emacs command.
+
+Sometimes `emacs.pkgs.withPackages` is not enough, as this package set has some priorities imposed on packages (with the lowest priority assigned to Melpa Unstable, and the highest for packages manually defined in `pkgs/top-level/emacs-packages.nix`). But you can't control these priorities when some package is installed as a dependency. You can override it on a per-package-basis, providing all the required dependencies manually, but it's tedious and there is always a possibility that an unwanted dependency will sneak in through some other package. To completely override such a package, you can use `overrideScope'`.
+
+```nix
+overrides = self: super: rec {
+  haskell-mode = self.melpaPackages.haskell-mode;
+  ...
+};
+((emacsPackagesFor emacs).overrideScope' overrides).withPackages
+  (p: with p; [
+    # here both these package will use haskell-mode of our own choice
+    ghc-mod
+    dante
+  ])
+```

doc/builders/packages/etc-files.section.md

@@ -0,0 +1,18 @@
+# /etc files {#etc}
+
+Certain calls in glibc require access to runtime files found in `/etc` such as `/etc/protocols` or `/etc/services` -- [getprotobyname](https://linux.die.net/man/3/getprotobyname) is one such function.
+
+On non-NixOS distributions these files are typically provided by packages (i.e., [netbase](https://packages.debian.org/sid/netbase)) if not already pre-installed in your distribution. This can cause non-reproducibility for code if they rely on these files being present.
+
+If [iana-etc](https://hydra.nixos.org/job/nixos/trunk-combined/nixpkgs.iana-etc.x86_64-linux) is part of your `buildInputs`, then it will set the environment variables `NIX_ETC_PROTOCOLS` and `NIX_ETC_SERVICES` to the corresponding files in the package through a setup hook.
+
+
+```bash
+> nix-shell -p iana-etc
+
+[nix-shell:~]$ env | grep NIX_ETC
+NIX_ETC_SERVICES=/nix/store/aj866hr8fad8flnggwdhrldm0g799ccz-iana-etc-20210225/etc/services
+NIX_ETC_PROTOCOLS=/nix/store/aj866hr8fad8flnggwdhrldm0g799ccz-iana-etc-20210225/etc/protocols
+```
+
+Nixpkg's version of [glibc](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/libraries/glibc/default.nix) has been patched to check for the existence of these environment variables. If the environment variables are *not* set, then it will attempt to find the files at the default location within `/etc`.

doc/builders/packages/firefox.section.md

@@ -0,0 +1,55 @@
+# Firefox {#sec-firefox}
+
+## Build wrapped Firefox with extensions and policies {#build-wrapped-firefox-with-extensions-and-policies}
+
+The `wrapFirefox` function allows to pass policies, preferences and extensions that are available to Firefox. With the help of `fetchFirefoxAddon` this allows to build a Firefox version that already comes with add-ons pre-installed:
+
+```nix
+{
+  # Nix firefox addons only work with the firefox-esr package.
+  myFirefox = wrapFirefox firefox-esr-unwrapped {
+    nixExtensions = [
+      (fetchFirefoxAddon {
+        name = "ublock"; # Has to be unique!
+        url = "https://addons.mozilla.org/firefox/downloads/file/3679754/ublock_origin-1.31.0-an+fx.xpi";
+        sha256 = "1h768ljlh3pi23l27qp961v1hd0nbj2vasgy11bmcrlqp40zgvnr";
+      })
+    ];
+
+    extraPolicies = {
+      CaptivePortal = false;
+      DisableFirefoxStudies = true;
+      DisablePocket = true;
+      DisableTelemetry = true;
+      DisableFirefoxAccounts = true;
+      FirefoxHome = {
+        Pocket = false;
+        Snippets = false;
+      };
+      UserMessaging = {
+        ExtensionRecommendations = false;
+        SkipOnboarding = true;
+      };
+      SecurityDevices = {
+        # Use a proxy module rather than `nixpkgs.config.firefox.smartcardSupport = true`
+        "PKCS#11 Proxy Module" = "${pkgs.p11-kit}/lib/p11-kit-proxy.so";
+      };
+    };
+
+    extraPrefs = ''
+      // Show more ssl cert infos
+      lockPref("security.identityblock.show_extended_validation", true);
+    '';
+  };
+}
+```
+
+If `nixExtensions != null`, then all manually installed add-ons will be uninstalled from your browser profile.
+To view available enterprise policies, visit [enterprise policies](https://github.com/mozilla/policy-templates#enterprisepoliciesenabled)
+or type into the Firefox URL bar: `about:policies#documentation`.
+Nix installed add-ons do not have a valid signature, which is why signature verification is disabled. This does not compromise security because downloaded add-ons are checksummed and manual add-ons can't be installed. Also, make sure that the `name` field of `fetchFirefoxAddon` is unique. If you remove an add-on from the `nixExtensions` array, rebuild and start Firefox: the removed add-on will be completely removed with all of its settings.
+
+## Troubleshooting {#sec-firefox-troubleshooting}
+If add-ons are marked as broken or the signature is invalid, make sure you have Firefox ESR installed. Normal Firefox does not provide the ability anymore to disable signature verification for add-ons thus nix add-ons get disabled by the normal Firefox binary.
+
+If add-ons do not appear installed despite being defined in your nix configuration file, reset the local add-on state of your Firefox profile by clicking `Help -> More Troubleshooting Information -> Refresh Firefox`. This can happen if you switch from manual add-on mode to nix add-on mode and then back to manual mode and then again to nix add-on mode.

doc/builders/packages/fish.section.md

@@ -0,0 +1,50 @@
+# Fish {#sec-fish}
+
+Fish is a "smart and user-friendly command line shell" with support for plugins.
+
+
+## Vendor Fish scripts {#sec-fish-vendor}
+
+Any package may ship its own Fish completions, configuration snippets, and
+functions. Those should be installed to
+`$out/share/fish/vendor_{completions,conf,functions}.d` respectively.
+
+When the `programs.fish.enable` and
+`programs.fish.vendor.{completions,config,functions}.enable` options from the
+NixOS Fish module are set to true, those paths are symlinked in the current
+system environment and automatically loaded by Fish.
+
+
+## Packaging Fish plugins {#sec-fish-plugins-pkg}
+
+While packages providing standalone executables belong to the top level,
+packages which have the sole purpose of extending Fish belong to the
+`fishPlugins` scope and should be registered in
+`pkgs/shells/fish/plugins/default.nix`.
+
+The `buildFishPlugin` utility function can be used to automatically copy Fish
+scripts from `$src/{completions,conf,conf.d,functions}` to the standard vendor
+installation paths. It also sets up the test environment so that the optional
+`checkPhase` is executed in a Fish shell with other already packaged plugins
+and package-local Fish functions specified in `checkPlugins` and
+`checkFunctionDirs` respectively.
+
+See `pkgs/shells/fish/plugins/pure.nix` for an example of Fish plugin package
+using `buildFishPlugin` and running unit tests with the `fishtape` test runner.
+
+
+## Fish wrapper {#sec-fish-wrapper}
+
+The `wrapFish` package is a wrapper around Fish which can be used to create
+Fish shells initialized with some plugins as well as completions, configuration
+snippets and functions sourced from the given paths. This provides a convenient
+way to test Fish plugins and scripts without having to alter the environment.
+
+```nix
+wrapFish {
+  pluginPkgs = with fishPlugins; [ pure foreign-env ];
+  completionDirs = [];
+  functionDirs = [];
+  confDirs = [ "/path/to/some/fish/init/dir/" ];
+}
+```

doc/builders/packages/fuse.section.md

@@ -0,0 +1,45 @@
+# FUSE {#sec-fuse}
+
+Some packages rely on
+[FUSE](https://www.kernel.org/doc/html/latest/filesystems/fuse.html) to provide
+support for additional filesystems not supported by the kernel.
+
+In general, FUSE software are primarily developed for Linux but many of them can
+also run on macOS. Nixpkgs supports FUSE packages on macOS, but it requires
+[macFUSE](https://osxfuse.github.io) to be installed outside of Nix. macFUSE
+currently isn't packaged in Nixpkgs mainly because it includes a kernel
+extension, which isn't supported by Nix outside of NixOS.
+
+If a package fails to run on macOS with an error message similar to the
+following, it's a likely sign that you need to have macFUSE installed.
+
+    dyld: Library not loaded: /usr/local/lib/libfuse.2.dylib
+    Referenced from: /nix/store/w8bi72bssv0bnxhwfw3xr1mvn7myf37x-sshfs-fuse-2.10/bin/sshfs
+    Reason: image not found
+    [1]    92299 abort      /nix/store/w8bi72bssv0bnxhwfw3xr1mvn7myf37x-sshfs-fuse-2.10/bin/sshfs
+
+Package maintainers may often encounter the following error when building FUSE
+packages on macOS:
+
+    checking for fuse.h... no
+    configure: error: No fuse.h found.
+
+This happens on autoconf based projects that use `AC_CHECK_HEADERS` or
+`AC_CHECK_LIBS` to detect libfuse, and will occur even when the `fuse` package
+is included in `buildInputs`. It happens because libfuse headers throw an error
+on macOS if the `FUSE_USE_VERSION` macro is undefined. Many projects do define
+`FUSE_USE_VERSION`, but only inside C source files. This results in the above
+error at configure time because the configure script would attempt to compile
+sample FUSE programs without defining `FUSE_USE_VERSION`.
+
+There are two possible solutions for this problem in Nixpkgs:
+
+1. Pass `FUSE_USE_VERSION` to the configure script by adding
+   `CFLAGS=-DFUSE_USE_VERSION=25` in `configureFlags`. The actual value would
+   have to match the definition used in the upstream source code.
+2. Remove `AC_CHECK_HEADERS` / `AC_CHECK_LIBS` for libfuse.
+
+However, a better solution might be to fix the build script upstream to use
+`PKG_CHECK_MODULES` instead. This approach wouldn't suffer from the problem that
+`AC_CHECK_HEADERS`/`AC_CHECK_LIBS` has at the price of introducing a dependency
+on pkg-config.

doc/builders/packages/ibus.section.md

@@ -0,0 +1,38 @@
+# ibus-engines.typing-booster {#sec-ibus-typing-booster}
+
+This package is an ibus-based completion method to speed up typing.
+
+## Activating the engine {#sec-ibus-typing-booster-activate}
+
+IBus needs to be configured accordingly to activate `typing-booster`. The configuration depends on the desktop manager in use. For detailed instructions, please refer to the [upstream docs](https://mike-fabian.github.io/ibus-typing-booster/documentation.html).
+
+On NixOS, you need to explicitly enable `ibus` with given engines before customizing your desktop to use `typing-booster`. This can be achieved using the `ibus` module:
+
+```nix
+{ pkgs, ... }: {
+  i18n.inputMethod = {
+    enabled = "ibus";
+    ibus.engines = with pkgs.ibus-engines; [ typing-booster ];
+  };
+}
+```
+
+## Using custom hunspell dictionaries {#sec-ibus-typing-booster-customize-hunspell}
+
+The IBus engine is based on `hunspell` to support completion in many languages. By default, the dictionaries `de-de`, `en-us`, `fr-moderne` `es-es`, `it-it`, `sv-se` and `sv-fi` are in use. To add another dictionary, the package can be overridden like this:
+
+```nix
+ibus-engines.typing-booster.override { langs = [ "de-at" "en-gb" ]; }
+```
+
+_Note: each language passed to `langs` must be an attribute name in `pkgs.hunspellDicts`._
+
+## Built-in emoji picker {#sec-ibus-typing-booster-emoji-picker}
+
+The `ibus-engines.typing-booster` package contains a program named `emoji-picker`. To display all emojis correctly, a special font such as `noto-fonts-emoji` is needed:
+
+On NixOS, it can be installed using the following expression:
+
+```nix
+{ pkgs, ... }: { fonts.fonts = with pkgs; [ noto-fonts-emoji ]; }
+```

doc/builders/packages/index.xml

@@ -0,0 +1,29 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-packages">
+ <title>Packages</title>
+ <para>
+  This chapter contains information about how to use and maintain the Nix expressions for a number of specific packages, such as the Linux kernel or X.org.
+ </para>
+ <xi:include href="citrix.section.xml" />
+ <xi:include href="dlib.section.xml" />
+ <xi:include href="eclipse.section.xml" />
+ <xi:include href="elm.section.xml" />
+ <xi:include href="emacs.section.xml" />
+ <xi:include href="firefox.section.xml" />
+ <xi:include href="fish.section.xml" />
+ <xi:include href="fuse.section.xml" />
+ <xi:include href="ibus.section.xml" />
+ <xi:include href="kakoune.section.xml" />
+ <xi:include href="linux.section.xml" />
+ <xi:include href="locales.section.xml" />
+ <xi:include href="etc-files.section.xml" />
+ <xi:include href="nginx.section.xml" />
+ <xi:include href="opengl.section.xml" />
+ <xi:include href="shell-helpers.section.xml" />
+ <xi:include href="steam.section.xml" />
+ <xi:include href="cataclysm-dda.section.xml" />
+ <xi:include href="urxvt.section.xml" />
+ <xi:include href="weechat.section.xml" />
+ <xi:include href="xorg.section.xml" />
+</chapter>

doc/builders/packages/kakoune.section.md

@@ -0,0 +1,9 @@
+# Kakoune {#sec-kakoune}
+
+Kakoune can be built to autoload plugins:
+
+```nix
+(kakoune.override {
+  plugins = with pkgs.kakounePlugins; [ parinfer-rust ];
+})
+```

doc/builders/packages/linux.section.md

@@ -0,0 +1,41 @@
+# Linux kernel {#sec-linux-kernel}
+
+The Nix expressions to build the Linux kernel are in [`pkgs/os-specific/linux/kernel`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/os-specific/linux/kernel).
+
+The function that builds the kernel has an argument `kernelPatches` which should be a list of `{name, patch, extraConfig}` attribute sets, where `name` is the name of the patch (which is included in the kernel’s `meta.description` attribute), `patch` is the patch itself (possibly compressed), and `extraConfig` (optional) is a string specifying extra options to be concatenated to the kernel configuration file (`.config`).
+
+The kernel derivation exports an attribute `features` specifying whether optional functionality is or isn’t enabled. This is used in NixOS to implement kernel-specific behaviour. For instance, if the kernel has the `iwlwifi` feature (i.e., has built-in support for Intel wireless chipsets), then NixOS doesn’t have to build the external `iwlwifi` package:
+
+```nix
+modulesTree = [kernel]
+  ++ pkgs.lib.optional (!kernel.features ? iwlwifi) kernelPackages.iwlwifi
+  ++ ...;
+```
+
+How to add a new (major) version of the Linux kernel to Nixpkgs:
+
+1.  Copy the old Nix expression (e.g., `linux-2.6.21.nix`) to the new one (e.g., `linux-2.6.22.nix`) and update it.
+
+2.  Add the new kernel to the `kernels` attribute set in `linux-kernels.nix` (e.g., create an attribute `kernel_2_6_22`).
+
+3.  Now we’re going to update the kernel configuration. First unpack the kernel. Then for each supported platform (`i686`, `x86_64`, `uml`) do the following:
+
+    1.  Make a copy from the old config (e.g., `config-2.6.21-i686-smp`) to the new one (e.g., `config-2.6.22-i686-smp`).
+
+    2.  Copy the config file for this platform (e.g., `config-2.6.22-i686-smp`) to `.config` in the kernel source tree.
+
+    3.  Run `make oldconfig ARCH={i386,x86_64,um}` and answer all questions. (For the uml configuration, also add `SHELL=bash`.) Make sure to keep the configuration consistent between platforms (i.e., don’t enable some feature on `i686` and disable it on `x86_64`).
+
+    4.  If needed, you can also run `make menuconfig`:
+
+        ```ShellSession
+        $ nix-env -f "<nixpkgs>" -iA ncurses
+        $ export NIX_CFLAGS_LINK=-lncurses
+        $ make menuconfig ARCH=arch
+        ```
+
+    5.  Copy `.config` over the new config file (e.g., `config-2.6.22-i686-smp`).
+
+4.  Test building the kernel: `nix-build -A linuxKernel.kernels.kernel_2_6_22`. If it compiles, ship it! For extra credit, try booting NixOS with it.
+
+5.  It may be that the new kernel requires updating the external kernel modules and kernel-dependent packages listed in the `linuxPackagesFor` function in `linux-kernels.nix` (such as the NVIDIA drivers, AUFS, etc.). If the updated packages aren’t backwards compatible with older kernels, you may need to keep the older versions around.

doc/builders/packages/locales.section.md

@@ -0,0 +1,5 @@
+# Locales {#locales}
+
+To allow simultaneous use of packages linked against different versions of `glibc` with different locale archive formats, Nixpkgs patches `glibc` to rely on `LOCALE_ARCHIVE` environment variable.
+
+On non-NixOS distributions, this variable is obviously not set. This can cause regressions in language support or even crashes in some Nixpkgs-provided programs. The simplest way to mitigate this problem is exporting the `LOCALE_ARCHIVE` variable pointing to `${glibcLocales}/lib/locale/locale-archive`. The drawback (and the reason this is not the default) is the relatively large (a hundred MiB) size of the full set of locales. It is possible to build a custom set of locales by overriding parameters `allLocales` and `locales` of the package.

doc/builders/packages/nginx.section.md

@@ -0,0 +1,11 @@
+# Nginx {#sec-nginx}
+
+[Nginx](https://nginx.org) is a reverse proxy and lightweight webserver.
+
+## ETags on static files served from the Nix store {#sec-nginx-etag}
+
+HTTP has a couple of different mechanisms for caching to prevent clients from having to download the same content repeatedly if a resource has not changed since the last time it was requested. When nginx is used as a server for static files, it implements the caching mechanism based on the [`Last-Modified`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Last-Modified) response header automatically; unfortunately, it works by using filesystem timestamps to determine the value of the `Last-Modified` header. This doesn't give the desired behavior when the file is in the Nix store because all file timestamps are set to 0 (for reasons related to build reproducibility).
+
+Fortunately, HTTP supports an alternative (and more effective) caching mechanism: the [`ETag`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag) response header. The value of the `ETag` header specifies some identifier for the particular content that the server is sending (e.g., a hash). When a client makes a second request for the same resource, it sends that value back in an `If-None-Match` header. If the ETag value is unchanged, then the server does not need to resend the content.
+
+As of NixOS 19.09, the nginx package in Nixpkgs is patched such that when nginx serves a file out of `/nix/store`, the hash in the store path is used as the `ETag` header in the HTTP response, thus providing proper caching functionality. This happens automatically; you do not need to do modify any configuration to get this behavior.

doc/builders/packages/opengl.section.md

@@ -0,0 +1,15 @@
+# OpenGL {#sec-opengl}
+
+OpenGL support varies depending on which hardware is used and which drivers are available and loaded.
+
+Broadly, we support both GL vendors: Mesa and NVIDIA.
+
+## NixOS Desktop {#nixos-desktop}
+
+The NixOS desktop or other non-headless configurations are the primary target for OpenGL libraries and applications. The current solution for discovering which drivers are available is based on [libglvnd](https://gitlab.freedesktop.org/glvnd/libglvnd). `libglvnd` performs "vendor-neutral dispatch", trying a variety of techniques to find the system's GL implementation. In practice, this will be either via standard GLX for X11 users or EGL for Wayland users, and supporting either NVIDIA or Mesa extensions.
+
+## Nix on GNU/Linux {#nix-on-gnulinux}
+
+If you are using a non-NixOS GNU/Linux/X11 desktop with free software video drivers, consider launching OpenGL-dependent programs from Nixpkgs with Nixpkgs versions of `libglvnd` and `mesa.drivers` in `LD_LIBRARY_PATH`. For Mesa drivers, the Linux kernel version doesn't have to match nixpkgs.
+
+For proprietary video drivers, you might have luck with also adding the corresponding video driver package.

doc/builders/packages/shell-helpers.section.md

@@ -0,0 +1,12 @@
+# Interactive shell helpers {#sec-shell-helpers}
+
+Some packages provide the shell integration to be more useful. But unlike other systems, nix doesn't have a standard `share` directory location. This is why a bunch `PACKAGE-share` scripts are shipped that print the location of the corresponding shared folder. Current list of such packages is as following:
+
+- `fzf` : `fzf-share`
+
+E.g. `fzf` can then be used in the `.bashrc` like this:
+
+```bash
+source "$(fzf-share)/completion.bash"
+source "$(fzf-share)/key-bindings.bash"
+```

doc/builders/packages/steam.section.md

@@ -0,0 +1,63 @@
+# Steam {#sec-steam}
+
+## Steam in Nix {#sec-steam-nix}
+
+Steam is distributed as a `.deb` file, for now only as an i686 package (the amd64 package only has documentation). When unpacked, it has a script called `steam` that in Ubuntu (their target distro) would go to `/usr/bin`. When run for the first time, this script copies some files to the user's home, which include another script that is the ultimate responsible for launching the steam binary, which is also in `$HOME`.
+
+Nix problems and constraints:
+
+- We don't have `/bin/bash` and many scripts point there. Same thing for `/usr/bin/python`.
+- We don't have the dynamic loader in `/lib`.
+- The `steam.sh` script in `$HOME` cannot be patched, as it is checked and rewritten by steam.
+- The steam binary cannot be patched, it's also checked.
+
+The current approach to deploy Steam in NixOS is composing a FHS-compatible chroot environment, as documented [here](http://sandervanderburg.blogspot.nl/2013/09/composing-fhs-compatible-chroot.html). This allows us to have binaries in the expected paths without disrupting the system, and to avoid patching them to work in a non FHS environment.
+
+## How to play {#sec-steam-play}
+
+Use `programs.steam.enable = true;` if you want to add steam to `systemPackages` and also enable a few workarounds as well as Steam controller support or other Steam supported controllers such as the DualShock 4 or Nintendo Switch Pro Controller.
+
+## Troubleshooting {#sec-steam-troub}
+
+- **Steam fails to start. What do I do?**
+
+  Try to run
+
+  ```ShellSession
+  strace steam
+  ```
+
+  to see what is causing steam to fail.
+
+- **Using the FOSS Radeon or nouveau (nvidia) drivers**
+
+  - The `newStdcpp` parameter was removed since NixOS 17.09 and should not be needed anymore.
+  - Steam ships statically linked with a version of `libcrypto` that conflicts with the one dynamically loaded by radeonsi_dri.so. If you get the error:
+
+    ```
+    steam.sh: line 713: 7842 Segmentation fault (core dumped)
+    ```
+
+    have a look at [this pull request](https://github.com/NixOS/nixpkgs/pull/20269).
+
+- **Java**
+
+  1. There is no java in steam chrootenv by default. If you get a message like:
+
+    ```
+    /home/foo/.local/share/Steam/SteamApps/common/towns/towns.sh: line 1: java: command not found
+    ```
+
+    you need to add:
+
+    ```nix
+    steam.override { withJava = true; };
+    ```
+
+## steam-run {#sec-steam-run}
+
+The FHS-compatible chroot used for Steam can also be used to run other Linux games that expect a FHS environment. To use it, install the `steam-run` package and run the game with:
+
+```
+steam-run ./foo
+```

doc/builders/packages/unfree.xml

@@ -0,0 +1,13 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xml:id="unfree-software">
+ <title>Unfree software</title>
+
+ <para>
+  All users of Nixpkgs are free software users, and many users (and developers) of Nixpkgs want to limit and tightly control their exposure to unfree software. At the same time, many users need (or want) to run some specific pieces of proprietary software. Nixpkgs includes some expressions for unfree software packages. By default unfree software cannot be installed and doesn’t show up in searches. To allow installing unfree software in a single Nix invocation one can export <literal>NIXPKGS_ALLOW_UNFREE=1</literal>. For a persistent solution, users can set <literal>allowUnfree</literal> in the Nixpkgs configuration.
+ </para>
+
+ <para>
+  Fine-grained control is possible by defining <literal>allowUnfreePredicate</literal> function in config; it takes the <literal>mkDerivation</literal> parameter attrset and returns <literal>true</literal> for unfree packages that should be allowed.
+ </para>
+</section>

doc/builders/packages/urxvt.section.md

@@ -0,0 +1,71 @@
+# Urxvt {#sec-urxvt}
+
+Urxvt, also known as rxvt-unicode, is a highly customizable terminal emulator.
+
+## Configuring urxvt {#sec-urxvt-conf}
+
+In `nixpkgs`, urxvt is provided by the package `rxvt-unicode`. It can be configured to include your choice of plugins, reducing its closure size from the default configuration which includes all available plugins. To make use of this functionality, use an overlay or directly install an expression that overrides its configuration, such as:
+
+```nix
+rxvt-unicode.override {
+  configure = { availablePlugins, ... }: {
+    plugins = with availablePlugins; [ perls resize-font vtwheel ];
+  };
+}
+```
+
+If the `configure` function returns an attrset without the `plugins` attribute, `availablePlugins` will be used automatically.
+
+In order to add plugins but also keep all default plugins installed, it is possible to use the following method:
+
+```nix
+rxvt-unicode.override {
+  configure = { availablePlugins, ... }: {
+    plugins = (builtins.attrValues availablePlugins) ++ [ custom-plugin ];
+  };
+}
+```
+
+To get a list of all the plugins available, open the Nix REPL and run
+
+```ShellSession
+$ nix repl
+:l <nixpkgs>
+map (p: p.name) pkgs.rxvt-unicode.plugins
+```
+
+Alternatively, if your shell is bash or zsh and have completion enabled, simply type `nixpkgs.rxvt-unicode.plugins.<tab>`.
+
+In addition to `plugins` the options `extraDeps` and `perlDeps` can be used to install extra packages. `extraDeps` can be used, for example, to provide `xsel` (a clipboard manager) to the clipboard plugin, without installing it globally:
+
+```nix
+rxvt-unicode.override {
+  configure = { availablePlugins, ... }: {
+    pluginsDeps = [ xsel ];
+  };
+}
+```
+
+`perlDeps` is a handy way to provide Perl packages to your custom plugins (in `$HOME/.urxvt/ext`). For example, if you need `AnyEvent` you can do:
+
+```nix
+rxvt-unicode.override {
+  configure = { availablePlugins, ... }: {
+    perlDeps = with perlPackages; [ AnyEvent ];
+  };
+}
+```
+
+## Packaging urxvt plugins {#sec-urxvt-pkg}
+
+Urxvt plugins resides in `pkgs/applications/misc/rxvt-unicode-plugins`. To add a new plugin, create an expression in a subdirectory and add the package to the set in `pkgs/applications/misc/rxvt-unicode-plugins/default.nix`.
+
+A plugin can be any kind of derivation, the only requirement is that it should always install perl scripts in `$out/lib/urxvt/perl`. Look for existing plugins for examples.
+
+If the plugin is itself a Perl package that needs to be imported from other plugins or scripts, add the following passthrough:
+
+```nix
+passthru.perlPackages = [ "self" ];
+```
+
+This will make the urxvt wrapper pick up the dependency and set up the Perl path accordingly.

doc/builders/packages/weechat.section.md

@@ -0,0 +1,85 @@
+# WeeChat {#sec-weechat}
+
+WeeChat can be configured to include your choice of plugins, reducing its closure size from the default configuration which includes all available plugins. To make use of this functionality, install an expression that overrides its configuration, such as:
+
+```nix
+weechat.override {configure = {availablePlugins, ...}: {
+    plugins = with availablePlugins; [ python perl ];
+  }
+}
+```
+
+If the `configure` function returns an attrset without the `plugins` attribute, `availablePlugins` will be used automatically.
+
+The plugins currently available are `python`, `perl`, `ruby`, `guile`, `tcl` and `lua`.
+
+The Python and Perl plugins allows the addition of extra libraries. For instance, the `inotify.py` script in `weechat-scripts` requires D-Bus or libnotify, and the `fish.py` script requires `pycrypto`. To use these scripts, use the plugin's `withPackages` attribute:
+
+```nix
+weechat.override { configure = {availablePlugins, ...}: {
+    plugins = with availablePlugins; [
+            (python.withPackages (ps: with ps; [ pycrypto python-dbus ]))
+        ];
+    };
+}
+```
+
+In order to also keep all default plugins installed, it is possible to use the following method:
+
+```nix
+weechat.override { configure = { availablePlugins, ... }: {
+  plugins = builtins.attrValues (availablePlugins // {
+    python = availablePlugins.python.withPackages (ps: with ps; [ pycrypto python-dbus ]);
+  });
+}; }
+```
+
+WeeChat allows to set defaults on startup using the `--run-command`. The `configure` method can be used to pass commands to the program:
+
+```nix
+weechat.override {
+  configure = { availablePlugins, ... }: {
+    init = ''
+      /set foo bar
+      /server add libera irc.libera.chat
+    '';
+  };
+}
+```
+
+Further values can be added to the list of commands when running `weechat --run-command "your-commands"`.
+
+Additionally, it's possible to specify scripts to be loaded when starting `weechat`. These will be loaded before the commands from `init`:
+
+```nix
+weechat.override {
+  configure = { availablePlugins, ... }: {
+    scripts = with pkgs.weechatScripts; [
+      weechat-xmpp weechat-matrix-bridge wee-slack
+    ];
+    init = ''
+      /set plugins.var.python.jabber.key "val"
+    '':
+  };
+}
+```
+
+In `nixpkgs` there's a subpackage which contains derivations for WeeChat scripts. Such derivations expect a `passthru.scripts` attribute, which contains a list of all scripts inside the store path. Furthermore, all scripts have to live in `$out/share`. An exemplary derivation looks like this:
+
+```nix
+{ stdenv, fetchurl }:
+
+stdenv.mkDerivation {
+  name = "exemplary-weechat-script";
+  src = fetchurl {
+    url = "https://scripts.tld/your-scripts.tar.gz";
+    sha256 = "...";
+  };
+  passthru.scripts = [ "foo.py" "bar.lua" ];
+  installPhase = ''
+    mkdir $out/share
+    cp foo.py $out/share
+    cp bar.lua $out/share
+  '';
+}
+```

doc/builders/packages/xorg.section.md

@@ -0,0 +1,34 @@
+# X.org {#sec-xorg}
+
+The Nix expressions for the X.org packages reside in `pkgs/servers/x11/xorg/default.nix`. This file is automatically generated from lists of tarballs in an X.org release. As such it should not be modified directly; rather, you should modify the lists, the generator script or the file `pkgs/servers/x11/xorg/overrides.nix`, in which you can override or add to the derivations produced by the generator.
+
+## Katamari Tarballs {#katamari-tarballs}
+
+X.org upstream releases used to include [katamari](https://en.wiktionary.org/wiki/%E3%81%8B%E3%81%9F%E3%81%BE%E3%82%8A) releases, which included a holistic recommended version for each tarball, up until 7.7. To create a list of tarballs in a katamari release:
+
+```ShellSession
+export release="X11R7.7"
+export url="mirror://xorg/$release/src/everything/"
+cat $(PRINT_PATH=1 nix-prefetch-url $url | tail -n 1) \
+  | perl -e 'while (<>) { if (/(href|HREF)="([^"]*.bz2)"/) { print "$ENV{'url'}$2\n"; }; }' \
+  | sort > "tarballs-$release.list"
+```
+
+## Individual Tarballs {#individual-tarballs}
+
+The upstream release process for [X11R7.8](https://x.org/wiki/Releases/7.8/) does not include a planned katamari. Instead, each component of X.org is released as its own tarball. We maintain `pkgs/servers/x11/xorg/tarballs.list` as a list of tarballs for each individual package. This list includes X.org core libraries and protocol descriptions, extra newer X11 interface libraries, like `xorg.libxcb`, and classic utilities which are largely unused but still available if needed, like `xorg.imake`.
+
+## Generating Nix Expressions {#generating-nix-expressions}
+
+The generator is invoked as follows:
+
+```ShellSession
+cd pkgs/servers/x11/xorg
+<tarballs.list perl ./generate-expr-from-tarballs.pl
+```
+
+For each of the tarballs in the `.list` files, the script downloads it, unpacks it, and searches its `configure.ac` and `*.pc.in` files for dependencies. This information is used to generate `default.nix`. The generator caches downloaded tarballs between runs. Pay close attention to the `NOT FOUND: $NAME` messages at the end of the run, since they may indicate missing dependencies. (Some might be optional dependencies, however.)
+
+## Overriding the Generator {#overriding-the-generator}
+
+If the expression for a package requires derivation attributes that the generator cannot figure out automatically (say, `patches` or a `postInstall` hook), you should modify `pkgs/servers/x11/xorg/overrides.nix`.

doc/builders/special.xml

@@ -0,0 +1,10 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-special">
+ <title>Special builders</title>
+ <para>
+  This chapter describes several special builders.
+ </para>
+ <xi:include href="special/fhs-environments.section.xml" />
+ <xi:include href="special/mkshell.section.xml" />
+</chapter>

doc/builders/special/fhs-environments.section.md

@@ -0,0 +1,49 @@
+# buildFHSUserEnv {#sec-fhs-environments}
+
+`buildFHSUserEnv` provides a way to build and run FHS-compatible lightweight sandboxes. It creates an isolated root with bound `/nix/store`, so its footprint in terms of disk space needed is quite small. This allows one to run software which is hard or unfeasible to patch for NixOS -- 3rd-party source trees with FHS assumptions, games distributed as tarballs, software with integrity checking and/or external self-updated binaries. It uses Linux namespaces feature to create temporary lightweight environments which are destroyed after all child processes exit, without root user rights requirement. Accepted arguments are:
+
+- `name`
+        Environment name.
+- `targetPkgs`
+        Packages to be installed for the main host's architecture (i.e. x86_64 on x86_64 installations). Along with libraries binaries are also installed.
+- `multiPkgs`
+        Packages to be installed for all architectures supported by a host (i.e. i686 and x86_64 on x86_64 installations). Only libraries are installed by default.
+- `extraBuildCommands`
+        Additional commands to be executed for finalizing the directory structure.
+- `extraBuildCommandsMulti`
+        Like `extraBuildCommands`, but executed only on multilib architectures.
+- `extraOutputsToInstall`
+        Additional derivation outputs to be linked for both target and multi-architecture packages.
+- `extraInstallCommands`
+        Additional commands to be executed for finalizing the derivation with runner script.
+- `runScript`
+        A command that would be executed inside the sandbox and passed all the command line arguments. It defaults to `bash`.
+- `profile`
+        Optional script for `/etc/profile` within the sandbox.
+
+One can create a simple environment using a `shell.nix` like that:
+
+```nix
+{ pkgs ? import <nixpkgs> {} }:
+
+(pkgs.buildFHSUserEnv {
+  name = "simple-x11-env";
+  targetPkgs = pkgs: (with pkgs;
+    [ udev
+      alsa-lib
+    ]) ++ (with pkgs.xorg;
+    [ libX11
+      libXcursor
+      libXrandr
+    ]);
+  multiPkgs = pkgs: (with pkgs;
+    [ udev
+      alsa-lib
+    ]);
+  runScript = "bash";
+}).env
+```
+
+Running `nix-shell` would then drop you into a shell with these libraries and binaries available. You can use this to run closed-source applications which expect FHS structure without hassles: simply change `runScript` to the application path, e.g. `./bin/start.sh` -- relative paths are supported.
+
+Additionally, the FHS builder links all relocated gsettings-schemas (the glib setup-hook moves them to `share/gsettings-schemas/${name}/glib-2.0/schemas`) to their standard FHS location. This means you don't need to wrap binaries with `wrapGAppsHook`.

doc/builders/special/mkshell.section.md

@@ -0,0 +1,37 @@
+# pkgs.mkShell {#sec-pkgs-mkShell}
+
+`pkgs.mkShell` is a specialized `stdenv.mkDerivation` that removes some
+repetition when using it with `nix-shell` (or `nix develop`).
+
+## Usage {#sec-pkgs-mkShell-usage}
+
+Here is a common usage example:
+
+```nix
+{ pkgs ? import <nixpkgs> {} }:
+pkgs.mkShell {
+  packages = [ pkgs.gnumake ];
+
+  inputsFrom = [ pkgs.hello pkgs.gnutar ];
+
+  shellHook = ''
+    export DEBUG=1
+  '';
+}
+```
+
+## Attributes
+
+* `name` (default: `nix-shell`). Set the name of the derivation.
+* `packages` (default: `[]`). Add executable packages to the `nix-shell` environment.
+* `inputsFrom` (default: `[]`). Add build dependencies of the listed derivations to the `nix-shell` environment.
+* `shellHook` (default: `""`). Bash statements that are executed by `nix-shell`.
+
+... all the attributes of `stdenv.mkDerivation`.
+
+## Building the shell
+
+This derivation output will contain a text file that contains a reference to
+all the build inputs. This is useful in CI where we want to make sure that
+every derivation, and its dependencies, build properly. Or when creating a GC
+root so that the build dependencies don't get garbage-collected.

doc/builders/testers.chapter.md

@@ -0,0 +1,128 @@
+# Testers {#chap-testers}
+This chapter describes several testing builders which are available in the <literal>testers</literal> namespace.
+
+## `testVersion` {#tester-testVersion}
+
+Checks the command output contains the specified version
+
+Although simplistic, this test assures that the main program
+can run. While there's no substitute for a real test case,
+it does catch dynamic linking errors and such. It also provides
+some protection against accidentally building the wrong version,
+for example when using an 'old' hash in a fixed-output derivation.
+
+Examples:
+
+```nix
+passthru.tests.version = testVersion { package = hello; };
+
+passthru.tests.version = testVersion {
+  package = seaweedfs;
+  command = "weed version";
+};
+
+passthru.tests.version = testVersion {
+  package = key;
+  command = "KeY --help";
+  # Wrong '2.5' version in the code. Drop on next version.
+  version = "2.5";
+};
+```
+
+## `testEqualDerivation` {#tester-testEqualDerivation}
+
+Checks that two packages produce the exact same build instructions.
+
+This can be used to make sure that a certain difference of configuration,
+such as the presence of an overlay does not cause a cache miss.
+
+When the derivations are equal, the return value is an empty file.
+Otherwise, the build log explains the difference via `nix-diff`.
+
+Example:
+
+```nix
+testEqualDerivation
+  "The hello package must stay the same when enabling checks."
+  hello
+  (hello.overrideAttrs(o: { doCheck = true; }))
+```
+
+## `invalidateFetcherByDrvHash` {#tester-invalidateFetcherByDrvHash}
+
+Use the derivation hash to invalidate the output via name, for testing.
+
+Type: `(a@{ name, ... } -> Derivation) -> a -> Derivation`
+
+Normally, fixed output derivations can and should be cached by their output
+hash only, but for testing we want to re-fetch everytime the fetcher changes.
+
+Changes to the fetcher become apparent in the drvPath, which is a hash of
+how to fetch, rather than a fixed store path.
+By inserting this hash into the name, we can make sure to re-run the fetcher
+every time the fetcher changes.
+
+This relies on the assumption that Nix isn't clever enough to reuse its
+database of local store contents to optimize fetching.
+
+You might notice that the "salted" name derives from the normal invocation,
+not the final derivation. `invalidateFetcherByDrvHash` has to invoke the fetcher
+function twice: once to get a derivation hash, and again to produce the final
+fixed output derivation.
+
+Example:
+
+```nix
+tests.fetchgit = invalidateFetcherByDrvHash fetchgit {
+  name = "nix-source";
+  url = "https://github.com/NixOS/nix";
+  rev = "9d9dbe6ed05854e03811c361a3380e09183f4f4a";
+  sha256 = "sha256-7DszvbCNTjpzGRmpIVAWXk20P0/XTrWZ79KSOGLrUWY=";
+};
+```
+
+## `nixosTest` {#tester-nixosTest}
+
+Run a NixOS VM network test using this evaluation of Nixpkgs.
+
+NOTE: This function is primarily for external use. NixOS itself uses `make-test-python.nix` directly. Packages defined in Nixpkgs [reuse NixOS tests via `nixosTests`, plural](#ssec-nixos-tests-linking).
+
+It is mostly equivalent to the function `import ./make-test-python.nix` from the
+[NixOS manual](https://nixos.org/nixos/manual/index.html#sec-nixos-tests),
+except that the current application of Nixpkgs (`pkgs`) will be used, instead of
+letting NixOS invoke Nixpkgs anew.
+
+If a test machine needs to set NixOS options under `nixpkgs`, it must set only the
+`nixpkgs.pkgs` option.
+
+### Parameter
+
+A [NixOS VM test network](https://nixos.org/nixos/manual/index.html#sec-nixos-tests), or path to it. Example:
+
+```nix
+{
+  name = "my-test";
+  nodes = {
+    machine1 = { lib, pkgs, nodes, ... }: {
+      environment.systemPackages = [ pkgs.hello ];
+      services.foo.enable = true;
+    };
+    # machine2 = ...;
+  };
+  testScript = ''
+    start_all()
+    machine1.wait_for_unit("foo.service")
+    machine1.succeed("hello | foo-send")
+  '';
+}
+```
+
+### Result
+
+A derivation that runs the VM test.
+
+Notable attributes:
+
+ * `nodes`: the evaluated NixOS configurations. Useful for debugging and exploring the configuration.
+
+ * `driverInteractive`: a script that launches an interactive Python session in the context of the `testScript`.

doc/builders/trivial-builders.chapter.md

@@ -0,0 +1,223 @@
+# Trivial builders {#chap-trivial-builders}
+
+Nixpkgs provides a couple of functions that help with building derivations. The most important one, `stdenv.mkDerivation`, has already been documented above. The following functions wrap `stdenv.mkDerivation`, making it easier to use in certain cases.
+
+## `runCommand` {#trivial-builder-runCommand}
+
+This takes three arguments, `name`, `env`, and `buildCommand`. `name` is just the name that Nix will append to the store path in the same way that `stdenv.mkDerivation` uses its `name` attribute. `env` is an attribute set specifying environment variables that will be set for this derivation. These attributes are then passed to the wrapped `stdenv.mkDerivation`. `buildCommand` specifies the commands that will be run to create this derivation. Note that you will need to create `$out` for Nix to register the command as successful.
+
+An example of using `runCommand` is provided below.
+
+```nix
+(import <nixpkgs> {}).runCommand "my-example" {} ''
+  echo My example command is running
+
+  mkdir $out
+
+  echo I can write data to the Nix store > $out/message
+
+  echo I can also run basic commands like:
+
+  echo ls
+  ls
+
+  echo whoami
+  whoami
+
+  echo date
+  date
+''
+```
+
+## `runCommandCC` {#trivial-builder-runCommandCC}
+
+This works just like `runCommand`. The only difference is that it also provides a C compiler in `buildCommand`'s environment. To minimize your dependencies, you should only use this if you are sure you will need a C compiler as part of running your command.
+
+## `runCommandLocal` {#trivial-builder-runCommandLocal}
+
+Variant of `runCommand` that forces the derivation to be built locally, it is not substituted. This is intended for very cheap commands (<1s execution time). It saves on the network round-trip and can speed up a build.
+
+::: {.note}
+This sets [`allowSubstitutes` to `false`](https://nixos.org/nix/manual/#adv-attr-allowSubstitutes), so only use `runCommandLocal` if you are certain the user will always have a builder for the `system` of the derivation. This should be true for most trivial use cases (e.g., just copying some files to a different location or adding symlinks) because there the `system` is usually the same as `builtins.currentSystem`.
+:::
+
+## `writeTextFile`, `writeText`, `writeTextDir`, `writeScript`, `writeScriptBin` {#trivial-builder-writeText}
+
+These functions write `text` to the Nix store. This is useful for creating scripts from Nix expressions. `writeTextFile` takes an attribute set and expects two arguments, `name` and `text`. `name` corresponds to the name used in the Nix store path. `text` will be the contents of the file. You can also set `executable` to true to make this file have the executable bit set.
+
+Many more commands wrap `writeTextFile` including `writeText`, `writeTextDir`, `writeScript`, and `writeScriptBin`. These are convenience functions over `writeTextFile`.
+
+Here are a few examples:
+```nix
+# Writes my-file to /nix/store/<store path>
+writeTextFile {
+  name = "my-file";
+  text = ''
+    Contents of File
+  '';
+}
+# See also the `writeText` helper function below.
+
+# Writes executable my-file to /nix/store/<store path>/bin/my-file
+writeTextFile {
+  name = "my-file";
+  text = ''
+    Contents of File
+  '';
+  executable = true;
+  destination = "/bin/my-file";
+}
+# Writes contents of file to /nix/store/<store path>
+writeText "my-file"
+  ''
+  Contents of File
+  '';
+# Writes contents of file to /nix/store/<store path>/share/my-file
+writeTextDir "share/my-file"
+  ''
+  Contents of File
+  '';
+# Writes my-file to /nix/store/<store path> and makes executable
+writeScript "my-file"
+  ''
+  Contents of File
+  '';
+# Writes my-file to /nix/store/<store path>/bin/my-file and makes executable.
+writeScriptBin "my-file"
+  ''
+  Contents of File
+  '';
+# Writes my-file to /nix/store/<store path> and makes executable.
+writeShellScript "my-file"
+  ''
+  Contents of File
+  '';
+# Writes my-file to /nix/store/<store path>/bin/my-file and makes executable.
+writeShellScriptBin "my-file"
+  ''
+  Contents of File
+  '';
+
+```
+
+## `concatTextFile`, `concatText`, `concatScript` {#trivial-builder-concatText}
+
+These functions concatenate `files` to the Nix store in a single file. This is useful for configuration files structured in lines of text. `concatTextFile` takes an attribute set and expects two arguments, `name` and `files`. `name` corresponds to the name used in the Nix store path. `files` will be the files to be concatenated. You can also set `executable` to true to make this file have the executable bit set.
+`concatText` and`concatScript` are simple wrappers over `concatTextFile`.
+
+Here are a few examples:
+```nix
+
+# Writes my-file to /nix/store/<store path>
+concatTextFile {
+  name = "my-file";
+  files = [ drv1 "${drv2}/path/to/file" ];
+}
+# See also the `concatText` helper function below.
+
+# Writes executable my-file to /nix/store/<store path>/bin/my-file
+concatTextFile {
+  name = "my-file";
+  files = [ drv1 "${drv2}/path/to/file" ];
+  executable = true;
+  destination = "/bin/my-file";
+}
+# Writes contents of files to /nix/store/<store path>
+concatText "my-file" [ file1 file2 ]
+
+# Writes contents of files to /nix/store/<store path>
+concatScript "my-file" [ file1 file2 ]
+```
+
+## `writeShellApplication` {#trivial-builder-writeShellApplication}
+
+This can be used to easily produce a shell script that has some dependencies (`runtimeInputs`). It automatically sets the `PATH` of the script to contain all of the listed inputs, sets some sanity shellopts (`errexit`, `nounset`, `pipefail`), and checks the resulting script with [`shellcheck`](https://github.com/koalaman/shellcheck).
+
+For example, look at the following code:
+
+```nix
+writeShellApplication {
+  name = "show-nixos-org";
+
+  runtimeInputs = [ curl w3m ];
+
+  text = ''
+    curl -s 'https://nixos.org' | w3m -dump -T text/html
+  '';
+}
+```
+
+Unlike with normal `writeShellScriptBin`, there is no need to manually write out `${curl}/bin/curl`, setting the PATH
+was handled by `writeShellApplication`. Moreover, the script is being checked with `shellcheck` for more strict
+validation.
+
+## `symlinkJoin` {#trivial-builder-symlinkJoin}
+
+This can be used to put many derivations into the same directory structure. It works by creating a new derivation and adding symlinks to each of the paths listed. It expects two arguments, `name`, and `paths`. `name` is the name used in the Nix store path for the created derivation. `paths` is a list of paths that will be symlinked. These paths can be to Nix store derivations or any other subdirectory contained within.
+Here is an example:
+```nix
+# adds symlinks of hello and stack to current build and prints "links added"
+symlinkJoin { name = "myexample"; paths = [ pkgs.hello pkgs.stack ]; postBuild = "echo links added"; }
+```
+This creates a derivation with a directory structure like the following:
+```
+/nix/store/sglsr5g079a5235hy29da3mq3hv8sjmm-myexample
+|-- bin
+|   |-- hello -> /nix/store/qy93dp4a3rqyn2mz63fbxjg228hffwyw-hello-2.10/bin/hello
+|   `-- stack -> /nix/store/6lzdpxshx78281vy056lbk553ijsdr44-stack-2.1.3.1/bin/stack
+`-- share
+    |-- bash-completion
+    |   `-- completions
+    |       `-- stack -> /nix/store/6lzdpxshx78281vy056lbk553ijsdr44-stack-2.1.3.1/share/bash-completion/completions/stack
+    |-- fish
+    |   `-- vendor_completions.d
+    |       `-- stack.fish -> /nix/store/6lzdpxshx78281vy056lbk553ijsdr44-stack-2.1.3.1/share/fish/vendor_completions.d/stack.fish
+...
+```
+
+## `writeReferencesToFile` {#trivial-builder-writeReferencesToFile}
+
+Writes the closure of transitive dependencies to a file.
+
+This produces the equivalent of `nix-store -q --requisites`.
+
+For example,
+
+```nix
+writeReferencesToFile (writeScriptBin "hi" ''${hello}/bin/hello'')
+```
+
+produces an output path `/nix/store/<hash>-runtime-deps` containing
+
+```nix
+/nix/store/<hash>-hello-2.10
+/nix/store/<hash>-hi
+/nix/store/<hash>-libidn2-2.3.0
+/nix/store/<hash>-libunistring-0.9.10
+/nix/store/<hash>-glibc-2.32-40
+```
+
+You can see that this includes `hi`, the original input path,
+`hello`, which is a direct reference, but also
+the other paths that are indirectly required to run `hello`.
+
+## `writeDirectReferencesToFile` {#trivial-builder-writeDirectReferencesToFile}
+
+Writes the set of references to the output file, that is, their immediate dependencies.
+
+This produces the equivalent of `nix-store -q --references`.
+
+For example,
+
+```nix
+writeDirectReferencesToFile (writeScriptBin "hi" ''${hello}/bin/hello'')
+```
+
+produces an output path `/nix/store/<hash>-runtime-references` containing
+
+```nix
+/nix/store/<hash>-hello-2.10
+```
+
+but none of `hello`'s dependencies because those are not referenced directly
+by `hi`'s output.

doc/contributing/coding-conventions.chapter.md

@@ -0,0 +1,656 @@
+# Coding conventions {#chap-conventions}
+
+## Syntax {#sec-syntax}
+
+- Use 2 spaces of indentation per indentation level in Nix expressions, 4 spaces in shell scripts.
+
+- Do not use tab characters, i.e. configure your editor to use soft tabs. For instance, use `(setq-default indent-tabs-mode nil)` in Emacs. Everybody has different tab settings so it’s asking for trouble.
+
+- Use `lowerCamelCase` for variable names, not `UpperCamelCase`. Note, this rule does not apply to package attribute names, which instead follow the rules in [](#sec-package-naming).
+
+- Function calls with attribute set arguments are written as
+
+  ```nix
+  foo {
+    arg = ...;
+  }
+  ```
+
+  not
+
+  ```nix
+  foo
+  {
+    arg = ...;
+  }
+  ```
+
+  Also fine is
+
+  ```nix
+  foo { arg = ...; }
+  ```
+
+  if it's a short call.
+
+- In attribute sets or lists that span multiple lines, the attribute names or list elements should be aligned:
+
+  ```nix
+  # A long list.
+  list = [
+    elem1
+    elem2
+    elem3
+  ];
+
+  # A long attribute set.
+  attrs = {
+    attr1 = short_expr;
+    attr2 =
+      if true then big_expr else big_expr;
+  };
+
+  # Combined
+  listOfAttrs = [
+    {
+      attr1 = 3;
+      attr2 = "fff";
+    }
+    {
+      attr1 = 5;
+      attr2 = "ggg";
+    }
+  ];
+  ```
+
+- Short lists or attribute sets can be written on one line:
+
+  ```nix
+  # A short list.
+  list = [ elem1 elem2 elem3 ];
+
+  # A short set.
+  attrs = { x = 1280; y = 1024; };
+  ```
+
+- Breaking in the middle of a function argument can give hard-to-read code, like
+
+  ```nix
+  someFunction { x = 1280;
+    y = 1024; } otherArg
+    yetAnotherArg
+  ```
+
+  (especially if the argument is very large, spanning multiple lines).
+
+  Better:
+
+  ```nix
+  someFunction
+    { x = 1280; y = 1024; }
+    otherArg
+    yetAnotherArg
+  ```
+
+  or
+
+  ```nix
+  let res = { x = 1280; y = 1024; };
+  in someFunction res otherArg yetAnotherArg
+  ```
+
+- The bodies of functions, asserts, and withs are not indented to prevent a lot of superfluous indentation levels, i.e.
+
+  ```nix
+  { arg1, arg2 }:
+  assert system == "i686-linux";
+  stdenv.mkDerivation { ...
+  ```
+
+  not
+
+  ```nix
+  { arg1, arg2 }:
+    assert system == "i686-linux";
+      stdenv.mkDerivation { ...
+  ```
+
+- Function formal arguments are written as:
+
+  ```nix
+  { arg1, arg2, arg3 }:
+  ```
+
+  but if they don't fit on one line they're written as:
+
+  ```nix
+  { arg1, arg2, arg3
+  , arg4, ...
+  , # Some comment...
+    argN
+  }:
+  ```
+
+- Functions should list their expected arguments as precisely as possible. That is, write
+
+  ```nix
+  { stdenv, fetchurl, perl }: ...
+  ```
+
+  instead of
+
+  ```nix
+  args: with args; ...
+  ```
+
+  or
+
+  ```nix
+  { stdenv, fetchurl, perl, ... }: ...
+  ```
+
+  For functions that are truly generic in the number of arguments (such as wrappers around `mkDerivation`) that have some required arguments, you should write them using an `@`-pattern:
+
+  ```nix
+  { stdenv, doCoverageAnalysis ? false, ... } @ args:
+
+  stdenv.mkDerivation (args // {
+    ... if doCoverageAnalysis then "bla" else "" ...
+  })
+  ```
+
+  instead of
+
+  ```nix
+  args:
+
+  args.stdenv.mkDerivation (args // {
+    ... if args ? doCoverageAnalysis && args.doCoverageAnalysis then "bla" else "" ...
+  })
+  ```
+
+- Unnecessary string conversions should be avoided. Do
+
+  ```nix
+  rev = version;
+  ```
+
+  instead of
+
+  ```nix
+  rev = "${version}";
+  ```
+
+- Building lists conditionally _should_ be done with `lib.optional(s)` instead of using `if cond then [ ... ] else null` or `if cond then [ ... ] else [ ]`.
+
+  ```nix
+  buildInputs = lib.optional stdenv.isDarwin iconv;
+  ```
+
+  instead of
+
+  ```nix
+  buildInputs = if stdenv.isDarwin then [ iconv ] else null;
+  ```
+
+  As an exception, an explicit conditional expression with null can be used when fixing a important bug without triggering a mass rebuild.
+  If this is done a follow up pull request _should_ be created to change the code to `lib.optional(s)`.
+
+- Arguments should be listed in the order they are used, with the exception of `lib`, which always goes first.
+
+## Package naming {#sec-package-naming}
+
+The key words _must_, _must not_, _required_, _shall_, _shall not_, _should_, _should not_, _recommended_, _may_, and _optional_ in this section are to be interpreted as described in [RFC 2119](https://tools.ietf.org/html/rfc2119). Only _emphasized_ words are to be interpreted in this way.
+
+In Nixpkgs, there are generally three different names associated with a package:
+
+- The `name` attribute of the derivation (excluding the version part). This is what most users see, in particular when using `nix-env`.
+
+- The variable name used for the instantiated package in `all-packages.nix`, and when passing it as a dependency to other functions. Typically this is called the _package attribute name_. This is what Nix expression authors see. It can also be used when installing using `nix-env -iA`.
+
+- The filename for (the directory containing) the Nix expression.
+
+Most of the time, these are the same. For instance, the package `e2fsprogs` has a `name` attribute `"e2fsprogs-version"`, is bound to the variable name `e2fsprogs` in `all-packages.nix`, and the Nix expression is in `pkgs/os-specific/linux/e2fsprogs/default.nix`.
+
+There are a few naming guidelines:
+
+- The `pname` attribute _should_ be identical to the upstream package name.
+
+- The `pname` and the `version` attribute _must not_ contain uppercase letters — e.g., `"mplayer" instead of `"MPlayer"`.
+
+- The `version` attribute _must_ start with a digit e.g`"0.3.1rc2".
+
+- If a package is not a release but a commit from a repository, then the `version` attribute _must_ be the date of that (fetched) commit. The date _must_ be in `"unstable-YYYY-MM-DD"` format.
+
+- Dashes in the package `pname` _should_ be preserved in new variable names, rather than converted to underscores or camel cased — e.g., `http-parser` instead of `http_parser` or `httpParser`. The hyphenated style is preferred in all three package names.
+
+- If there are multiple versions of a package, this _should_ be reflected in the variable names in `all-packages.nix`, e.g. `json-c_0_9` and `json-c_0_11`. If there is an obvious “default” version, make an attribute like `json-c = json-c_0_9;`. See also [](#sec-versioning)
+
+## File naming and organisation {#sec-organisation}
+
+Names of files and directories should be in lowercase, with dashes between words — not in camel case. For instance, it should be `all-packages.nix`, not `allPackages.nix` or `AllPackages.nix`.
+
+### Hierarchy {#sec-hierarchy}
+
+Each package should be stored in its own directory somewhere in the `pkgs/` tree, i.e. in `pkgs/category/subcategory/.../pkgname`. Below are some rules for picking the right category for a package. Many packages fall under several categories; what matters is the _primary_ purpose of a package. For example, the `libxml2` package builds both a library and some tools; but it’s a library foremost, so it goes under `pkgs/development/libraries`.
+
+When in doubt, consider refactoring the `pkgs/` tree, e.g. creating new categories or splitting up an existing category.
+
+**If it’s used to support _software development_:**
+
+- **If it’s a _library_ used by other packages:**
+
+  - `development/libraries` (e.g. `libxml2`)
+
+- **If it’s a _compiler_:**
+
+  - `development/compilers` (e.g. `gcc`)
+
+- **If it’s an _interpreter_:**
+
+  - `development/interpreters` (e.g. `guile`)
+
+- **If it’s a (set of) development _tool(s)_:**
+
+  - **If it’s a _parser generator_ (including lexers):**
+
+    - `development/tools/parsing` (e.g. `bison`, `flex`)
+
+  - **If it’s a _build manager_:**
+
+    - `development/tools/build-managers` (e.g. `gnumake`)
+
+  - **Else:**
+
+    - `development/tools/misc` (e.g. `binutils`)
+
+- **Else:**
+
+  - `development/misc`
+
+**If it’s a (set of) _tool(s)_:**
+
+(A tool is a relatively small program, especially one intended to be used non-interactively.)
+
+- **If it’s for _networking_:**
+
+  - `tools/networking` (e.g. `wget`)
+
+- **If it’s for _text processing_:**
+
+  - `tools/text` (e.g. `diffutils`)
+
+- **If it’s a _system utility_, i.e., something related or essential to the operation of a system:**
+
+  - `tools/system` (e.g. `cron`)
+
+- **If it’s an _archiver_ (which may include a compression function):**
+
+  - `tools/archivers` (e.g. `zip`, `tar`)
+
+- **If it’s a _compression_ program:**
+
+  - `tools/compression` (e.g. `gzip`, `bzip2`)
+
+- **If it’s a _security_-related program:**
+
+  - `tools/security` (e.g. `nmap`, `gnupg`)
+
+- **Else:**
+
+  - `tools/misc`
+
+**If it’s a _shell_:**
+
+- `shells` (e.g. `bash`)
+
+**If it’s a _server_:**
+
+- **If it’s a web server:**
+
+  - `servers/http` (e.g. `apache-httpd`)
+
+- **If it’s an implementation of the X Windowing System:**
+
+  - `servers/x11` (e.g. `xorg` — this includes the client libraries and programs)
+
+- **Else:**
+
+  - `servers/misc`
+
+**If it’s a _desktop environment_:**
+
+- `desktops` (e.g. `kde`, `gnome`, `enlightenment`)
+
+**If it’s a _window manager_:**
+
+- `applications/window-managers` (e.g. `awesome`, `stumpwm`)
+
+**If it’s an _application_:**
+
+A (typically large) program with a distinct user interface, primarily used interactively.
+
+- **If it’s a _version management system_:**
+
+  - `applications/version-management` (e.g. `subversion`)
+
+- **If it’s a _terminal emulator_:**
+
+  - `applications/terminal-emulators` (e.g. `alacritty` or `rxvt` or `termite`)
+
+- **If it’s for _video playback / editing_:**
+
+  - `applications/video` (e.g. `vlc`)
+
+- **If it’s for _graphics viewing / editing_:**
+
+  - `applications/graphics` (e.g. `gimp`)
+
+- **If it’s for _networking_:**
+
+  - **If it’s a _mailreader_:**
+
+    - `applications/networking/mailreaders` (e.g. `thunderbird`)
+
+  - **If it’s a _newsreader_:**
+
+    - `applications/networking/newsreaders` (e.g. `pan`)
+
+  - **If it’s a _web browser_:**
+
+    - `applications/networking/browsers` (e.g. `firefox`)
+
+  - **Else:**
+
+    - `applications/networking/misc`
+
+- **Else:**
+
+  - `applications/misc`
+
+**If it’s _data_ (i.e., does not have a straight-forward executable semantics):**
+
+- **If it’s a _font_:**
+
+  - `data/fonts`
+
+- **If it’s an _icon theme_:**
+
+  - `data/icons`
+
+- **If it’s related to _SGML/XML processing_:**
+
+  - **If it’s an _XML DTD_:**
+
+    - `data/sgml+xml/schemas/xml-dtd` (e.g. `docbook`)
+
+  - **If it’s an _XSLT stylesheet_:**
+
+    (Okay, these are executable...)
+
+    - `data/sgml+xml/stylesheets/xslt` (e.g. `docbook-xsl`)
+
+- **If it’s a _theme_ for a _desktop environment_, a _window manager_ or a _display manager_:**
+
+  - `data/themes`
+
+**If it’s a _game_:**
+
+- `games`
+
+**Else:**
+
+- `misc`
+
+### Versioning {#sec-versioning}
+
+Because every version of a package in Nixpkgs creates a potential maintenance burden, old versions of a package should not be kept unless there is a good reason to do so. For instance, Nixpkgs contains several versions of GCC because other packages don’t build with the latest version of GCC. Other examples are having both the latest stable and latest pre-release version of a package, or to keep several major releases of an application that differ significantly in functionality.
+
+If there is only one version of a package, its Nix expression should be named `e2fsprogs/default.nix`. If there are multiple versions, this should be reflected in the filename, e.g. `e2fsprogs/1.41.8.nix` and `e2fsprogs/1.41.9.nix`. The version in the filename should leave out unnecessary detail. For instance, if we keep the latest Firefox 2.0.x and 3.5.x versions in Nixpkgs, they should be named `firefox/2.0.nix` and `firefox/3.5.nix`, respectively (which, at a given point, might contain versions `2.0.0.20` and `3.5.4`). If a version requires many auxiliary files, you can use a subdirectory for each version, e.g. `firefox/2.0/default.nix` and `firefox/3.5/default.nix`.
+
+All versions of a package _must_ be included in `all-packages.nix` to make sure that they evaluate correctly.
+
+## Fetching Sources {#sec-sources}
+
+There are multiple ways to fetch a package source in nixpkgs. The general guideline is that you should package reproducible sources with a high degree of availability. Right now there is only one fetcher which has mirroring support and that is `fetchurl`. Note that you should also prefer protocols which have a corresponding proxy environment variable.
+
+You can find many source fetch helpers in `pkgs/build-support/fetch*`.
+
+In the file `pkgs/top-level/all-packages.nix` you can find fetch helpers, these have names on the form `fetchFrom*`. The intention of these are to provide snapshot fetches but using the same api as some of the version controlled fetchers from `pkgs/build-support/`. As an example going from bad to good:
+
+- Bad: Uses `git://` which won't be proxied.
+
+  ```nix
+  src = fetchgit {
+    url = "git://github.com/NixOS/nix.git";
+    rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
+    sha256 = "1cw5fszffl5pkpa6s6wjnkiv6lm5k618s32sp60kvmvpy7a2v9kg";
+  }
+  ```
+
+- Better: This is ok, but an archive fetch will still be faster.
+
+  ```nix
+  src = fetchgit {
+    url = "https://github.com/NixOS/nix.git";
+    rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
+    sha256 = "1cw5fszffl5pkpa6s6wjnkiv6lm5k618s32sp60kvmvpy7a2v9kg";
+  }
+  ```
+
+- Best: Fetches a snapshot archive and you get the rev you want.
+
+  ```nix
+  src = fetchFromGitHub {
+    owner = "NixOS";
+    repo = "nix";
+    rev = "1f795f9f44607cc5bec70d1300150bfefcef2aae";
+    sha256 = "1i2yxndxb6yc9l6c99pypbd92lfq5aac4klq7y2v93c9qvx2cgpc";
+  }
+  ```
+
+  Find the value to put as `sha256` by running `nix run -f '<nixpkgs>' nix-prefetch-github -c nix-prefetch-github --rev 1f795f9f44607cc5bec70d1300150bfefcef2aae NixOS nix` or `nix-prefetch-url --unpack https://github.com/NixOS/nix/archive/1f795f9f44607cc5bec70d1300150bfefcef2aae.tar.gz`.
+
+## Obtaining source hash {#sec-source-hashes}
+
+Preferred source hash type is sha256. There are several ways to get it.
+
+1. Prefetch URL (with `nix-prefetch-XXX URL`, where `XXX` is one of `url`, `git`, `hg`, `cvs`, `bzr`, `svn`). Hash is printed to stdout.
+
+2. Prefetch by package source (with `nix-prefetch-url '<nixpkgs>' -A PACKAGE.src`, where `PACKAGE` is package attribute name). Hash is printed to stdout.
+
+    This works well when you've upgraded existing package version and want to find out new hash, but is useless if package can't be accessed by attribute or package has multiple sources (`.srcs`, architecture-dependent sources, etc).
+
+3. Upstream provided hash: use it when upstream provides `sha256` or `sha512` (when upstream provides `md5`, don't use it, compute `sha256` instead).
+
+    A little nuance is that `nix-prefetch-*` tools produce hash encoded with `base32`, but upstream usually provides hexadecimal (`base16`) encoding. Fetchers understand both formats. Nixpkgs does not standardize on any one format.
+
+    You can convert between formats with nix-hash, for example:
+
+    ```ShellSession
+    $ nix-hash --type sha256 --to-base32 HASH
+    ```
+
+4. Extracting hash from local source tarball can be done with `sha256sum`. Use `nix-prefetch-url file:///path/to/tarball` if you want base32 hash.
+
+5. Fake hash: set fake hash in package expression, perform build and extract correct hash from error Nix prints.
+
+    For package updates it is enough to change one symbol to make hash fake. For new packages, you can use `lib.fakeSha256`, `lib.fakeSha512` or any other fake hash.
+
+    This is last resort method when reconstructing source URL is non-trivial and `nix-prefetch-url -A` isn’t applicable (for example, [one of `kodi` dependencies](https://github.com/NixOS/nixpkgs/blob/d2ab091dd308b99e4912b805a5eb088dd536adb9/pkgs/applications/video/kodi/default.nix#L73)). The easiest way then would be replace hash with a fake one and rebuild. Nix build will fail and error message will contain desired hash.
+
+::: {.warning}
+This method has security problems. Check below for details.
+:::
+
+### Obtaining hashes securely {#sec-source-hashes-security}
+
+Let's say Man-in-the-Middle (MITM) sits close to your network. Then instead of fetching source you can fetch malware, and instead of source hash you get hash of malware. Here are security considerations for this scenario:
+
+- `http://` URLs are not secure to prefetch hash from;
+
+- hashes from upstream (in method 3) should be obtained via secure protocol;
+
+- `https://` URLs are secure in methods 1, 2, 3;
+
+- `https://` URLs are not secure in method 5. When obtaining hashes with fake hash method, TLS checks are disabled. So refetch source hash from several different networks to exclude MITM scenario. Alternatively, use fake hash method to make Nix error, but instead of extracting hash from error, extract `https://` URL and prefetch it with method 1.
+
+## Patches {#sec-patches}
+
+Patches available online should be retrieved using `fetchpatch`.
+
+```nix
+patches = [
+  (fetchpatch {
+    name = "fix-check-for-using-shared-freetype-lib.patch";
+    url = "http://git.ghostscript.com/?p=ghostpdl.git;a=patch;h=8f5d285";
+    sha256 = "1f0k043rng7f0rfl9hhb89qzvvksqmkrikmm38p61yfx51l325xr";
+  })
+];
+```
+
+Otherwise, you can add a `.patch` file to the `nixpkgs` repository. In the interest of keeping our maintenance burden to a minimum, only patches that are unique to `nixpkgs` should be added in this way.
+
+If a patch is available online but does not cleanly apply, it can be modified in some fixed ways by using additional optional arguments for `fetchpatch`. Check [](#fetchpatch) for details.
+
+```nix
+patches = [ ./0001-changes.patch ];
+```
+
+If you do need to do create this sort of patch file, one way to do so is with git:
+
+1. Move to the root directory of the source code you're patching.
+
+    ```ShellSession
+    $ cd the/program/source
+    ```
+
+2. If a git repository is not already present, create one and stage all of the source files.
+
+    ```ShellSession
+    $ git init
+    $ git add .
+    ```
+
+3. Edit some files to make whatever changes need to be included in the patch.
+
+4. Use git to create a diff, and pipe the output to a patch file:
+
+    ```ShellSession
+    $ git diff -a > nixpkgs/pkgs/the/package/0001-changes.patch
+    ```
+
+## Package tests {#sec-package-tests}
+
+Tests are important to ensure quality and make reviews and automatic updates easy.
+
+The following types of tests exists:
+
+* [NixOS **module tests**](https://nixos.org/manual/nixos/stable/#sec-nixos-tests), which spawn one or more NixOS VMs. They exercise both NixOS modules and the packaged programs used within them. For example, a NixOS module test can start a web server VM running the `nginx` module, and a client VM running `curl` or a graphical `firefox`, and test that they can talk to each other and display the correct content.
+* Nix **package tests** are a lightweight alternative to NixOS module tests. They should be used to create simple integration tests for packages, but cannot test NixOS services, and some programs with graphical user interfaces may also be difficult to test with them.
+* The **`checkPhase` of a package**, which should execute the unit tests that are included in the source code of a package.
+
+Here in the nixpkgs manual we describe mostly _package tests_; for _module tests_ head over to the corresponding [section in the NixOS manual](https://nixos.org/manual/nixos/stable/#sec-nixos-tests).
+
+### Writing inline package tests {#ssec-inline-package-tests-writing}
+
+For very simple tests, they can be written inline:
+
+```nix
+{ …, yq-go }:
+
+buildGoModule rec {
+  …
+
+  passthru.tests = {
+    simple = runCommand "${pname}-test" {} ''
+      echo "test: 1" | ${yq-go}/bin/yq eval -j > $out
+      [ "$(cat $out | tr -d $'\n ')" = '{"test":1}' ]
+    '';
+  };
+}
+```
+
+### Writing larger package tests {#ssec-package-tests-writing}
+
+This is an example using the `phoronix-test-suite` package with the current best practices.
+
+Add the tests in `passthru.tests` to the package definition like this:
+
+```nix
+{ stdenv, lib, fetchurl, callPackage }:
+
+stdenv.mkDerivation {
+  …
+
+  passthru.tests = {
+    simple-execution = callPackage ./tests.nix { };
+  };
+
+  meta = { … };
+}
+```
+
+Create `tests.nix` in the package directory:
+
+```nix
+{ runCommand, phoronix-test-suite }:
+
+let
+  inherit (phoronix-test-suite) pname version;
+in
+
+runCommand "${pname}-tests" { meta.timeout = 60; }
+  ''
+    # automatic initial setup to prevent interactive questions
+    ${phoronix-test-suite}/bin/phoronix-test-suite enterprise-setup >/dev/null
+    # get version of installed program and compare with package version
+    if [[ `${phoronix-test-suite}/bin/phoronix-test-suite version` != *"${version}"*  ]]; then
+      echo "Error: program version does not match package version"
+      exit 1
+    fi
+    # run dummy command
+    ${phoronix-test-suite}/bin/phoronix-test-suite dummy_module.dummy-command >/dev/null
+    # needed for Nix to register the command as successful
+    touch $out
+  ''
+```
+
+### Running package tests {#ssec-package-tests-running}
+
+You can run these tests with:
+
+```ShellSession
+$ cd path/to/nixpkgs
+$ nix-build -A phoronix-test-suite.tests
+```
+
+### Examples of package tests {#ssec-package-tests-examples}
+
+Here are examples of package tests:
+
+- [Jasmin compile test](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/compilers/jasmin/test-assemble-hello-world/default.nix)
+- [Lobster compile test](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/compilers/lobster/test-can-run-hello-world.nix)
+- [Spacy annotation test](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/python-modules/spacy/annotation-test/default.nix)
+- [Libtorch test](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/libraries/science/math/libtorch/test/default.nix)
+- [Multiple tests for nanopb](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/libraries/nanopb/default.nix)
+
+### Linking NixOS module tests to a package {#ssec-nixos-tests-linking}
+
+Like [package tests](#ssec-package-tests-writing) as shown above, [NixOS module tests](https://nixos.org/manual/nixos/stable/#sec-nixos-tests) can also be linked to a package, so that the tests can be easily run when changing the related package.
+
+For example, assuming we're packaging `nginx`, we can link its module test via `passthru.tests`:
+
+```nix
+{ stdenv, lib, nixosTests }:
+
+stdenv.mkDerivation {
+  ...
+
+  passthru.tests = {
+    nginx = nixosTests.nginx;
+  };
+
+  ...
+}
+```

doc/contributing/contributing-to-documentation.chapter.md

@@ -0,0 +1,106 @@
+# Contributing to this documentation {#chap-contributing}
+
+The sources of the Nixpkgs manual are in the [doc](https://github.com/NixOS/nixpkgs/tree/master/doc) subdirectory of the Nixpkgs repository. The manual is still partially written in DocBook but it is progressively being converted to [Markdown](#sec-contributing-markup).
+
+You can quickly check your edits with `make`:
+
+```ShellSession
+$ cd /path/to/nixpkgs/doc
+$ nix-shell
+[nix-shell]$ make
+```
+
+If you experience problems, run `make debug` to help understand the docbook errors.
+
+After making modifications to the manual, it's important to build it before committing. You can do that as follows:
+
+```ShellSession
+$ cd /path/to/nixpkgs/doc
+$ nix-shell
+[nix-shell]$ make clean
+[nix-shell]$ nix-build .
+```
+
+If the build succeeds, the manual will be in `./result/share/doc/nixpkgs/manual.html`.
+
+## Syntax {#sec-contributing-markup}
+
+As per [RFC 0072](https://github.com/NixOS/rfcs/pull/72), all new documentation content should be written in [CommonMark](https://commonmark.org/) Markdown dialect.
+
+Additionally, the following syntax extensions are currently used:
+
+- []{#ssec-contributing-markup-anchors}
+  Explicitly defined **anchors** on headings, to allow linking to sections. These should be always used, to ensure the anchors can be linked even when the heading text changes, and to prevent conflicts between [automatically assigned identifiers](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/auto_identifiers.md).
+
+  It uses the widely compatible [header attributes](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/attributes.md) syntax:
+
+  ```markdown
+  ## Syntax {#sec-contributing-markup}
+  ```
+
+- []{#ssec-contributing-markup-anchors-inline}
+  **Inline anchors**, which allow linking arbitrary place in the text (e.g. individual list items, sentences…).
+
+  They are defined using a hybrid of the link syntax with the attributes syntax known from headings, called [bracketed spans](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/bracketed_spans.md):
+
+  ```markdown
+  - []{#ssec-gnome-hooks-glib} `glib` setup hook will populate `GSETTINGS_SCHEMAS_PATH` and then `wrapGAppsHook` will prepend it to `XDG_DATA_DIRS`.
+  ```
+
+- []{#ssec-contributing-markup-automatic-links}
+  If you **omit a link text** for a link pointing to a section, the text will be substituted automatically. For example, `[](#chap-contributing)` will result in [](#chap-contributing).
+
+  This syntax is taken from [MyST](https://myst-parser.readthedocs.io/en/latest/using/syntax.html#targets-and-cross-referencing).
+
+- []{#ssec-contributing-markup-inline-roles}
+  If you want to link to a man page, you can use `` {manpage}`nix.conf(5)` ``, which will turn into {manpage}`nix.conf(5)`.
+
+  The references will turn into links when a mapping exists in {file}`doc/build-aux/pandoc-filters/link-unix-man-references.lua`.
+
+  This syntax is taken from [MyST](https://myst-parser.readthedocs.io/en/latest/syntax/syntax.html#roles-an-in-line-extension-point). Though, the feature originates from [reStructuredText](https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html#role-manpage) with slightly different syntax.
+
+- []{#ssec-contributing-markup-admonitions}
+  **Admonitions**, set off from the text to bring attention to something.
+
+  It uses pandoc’s [fenced `div`s syntax](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/fenced_divs.md):
+
+  ```markdown
+  ::: {.warning}
+  This is a warning
+  :::
+  ```
+
+  which renders as
+
+  > ::: {.warning}
+  > This is a warning.
+  > :::
+
+  The following are supported:
+
+    - [`caution`](https://tdg.docbook.org/tdg/5.0/caution.html)
+    - [`important`](https://tdg.docbook.org/tdg/5.0/important.html)
+    - [`note`](https://tdg.docbook.org/tdg/5.0/note.html)
+    - [`tip`](https://tdg.docbook.org/tdg/5.0/tip.html)
+    - [`warning`](https://tdg.docbook.org/tdg/5.0/warning.html)
+
+- []{#ssec-contributing-markup-definition-lists}
+  [**Definition lists**](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/definition_lists.md), for defining a group of terms:
+
+  ```markdown
+  pear
+  :   green or yellow bulbous fruit
+
+  watermelon
+  :   green fruit with red flesh
+  ```
+
+  which renders as
+
+  > pear
+  > :   green or yellow bulbous fruit
+  >
+  > watermelon
+  > :   green fruit with red flesh
+
+For contributing to the legacy parts, please see [DocBook: The Definitive Guide](https://tdg.docbook.org/) or the [DocBook rocks! primer](https://web.archive.org/web/20200816233747/https://docbook.rocks/).

doc/contributing/quick-start.chapter.md

@@ -0,0 +1,77 @@
+# Quick Start to Adding a Package {#chap-quick-start}
+
+To add a package to Nixpkgs:
+
+1. Checkout the Nixpkgs source tree:
+
+   ```ShellSession
+   $ git clone https://github.com/NixOS/nixpkgs
+   $ cd nixpkgs
+   ```
+
+2. Find a good place in the Nixpkgs tree to add the Nix expression for your package. For instance, a library package typically goes into `pkgs/development/libraries/pkgname`, while a web browser goes into `pkgs/applications/networking/browsers/pkgname`. See [](#sec-organisation) for some hints on the tree organisation. Create a directory for your package, e.g.
+
+   ```ShellSession
+   $ mkdir pkgs/development/libraries/libfoo
+   ```
+
+3. In the package directory, create a Nix expression — a piece of code that describes how to build the package. In this case, it should be a _function_ that is called with the package dependencies as arguments, and returns a build of the package in the Nix store. The expression should usually be called `default.nix`.
+
+   ```ShellSession
+   $ emacs pkgs/development/libraries/libfoo/default.nix
+   $ git add pkgs/development/libraries/libfoo/default.nix
+   ```
+
+   You can have a look at the existing Nix expressions under `pkgs/` to see how it’s done. Here are some good ones:
+
+   - GNU Hello: [`pkgs/applications/misc/hello/default.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/misc/hello/default.nix). Trivial package, which specifies some `meta` attributes which is good practice.
+
+   - GNU cpio: [`pkgs/tools/archivers/cpio/default.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/tools/archivers/cpio/default.nix). Also a simple package. The generic builder in `stdenv` does everything for you. It has no dependencies beyond `stdenv`.
+
+   - GNU Multiple Precision arithmetic library (GMP): [`pkgs/development/libraries/gmp/5.1.x.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/libraries/gmp/5.1.x.nix). Also done by the generic builder, but has a dependency on `m4`.
+
+   - Pan, a GTK-based newsreader: [`pkgs/applications/networking/newsreaders/pan/default.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/networking/newsreaders/pan/default.nix). Has an optional dependency on `gtkspell`, which is only built if `spellCheck` is `true`.
+
+   - Apache HTTPD: [`pkgs/servers/http/apache-httpd/2.4.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/http/apache-httpd/2.4.nix). A bunch of optional features, variable substitutions in the configure flags, a post-install hook, and miscellaneous hackery.
+
+   - Thunderbird: [`pkgs/applications/networking/mailreaders/thunderbird/default.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/networking/mailreaders/thunderbird/default.nix). Lots of dependencies.
+
+   - JDiskReport, a Java utility: [`pkgs/tools/misc/jdiskreport/default.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/tools/misc/jdiskreport/default.nix). Nixpkgs doesn’t have a decent `stdenv` for Java yet so this is pretty ad-hoc.
+
+   - XML::Simple, a Perl module: [`pkgs/top-level/perl-packages.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/perl-packages.nix) (search for the `XMLSimple` attribute). Most Perl modules are so simple to build that they are defined directly in `perl-packages.nix`; no need to make a separate file for them.
+
+   - Adobe Reader: [`pkgs/applications/misc/adobe-reader/default.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/misc/adobe-reader/default.nix). Shows how binary-only packages can be supported. In particular the [builder](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/misc/adobe-reader/builder.sh) uses `patchelf` to set the RUNPATH and ELF interpreter of the executables so that the right libraries are found at runtime.
+
+   Some notes:
+
+   - All [`meta`](#chap-meta) attributes are optional, but it’s still a good idea to provide at least the `description`, `homepage` and [`license`](#sec-meta-license).
+
+   - You can use `nix-prefetch-url url` to get the SHA-256 hash of source distributions. There are similar commands as `nix-prefetch-git` and `nix-prefetch-hg` available in `nix-prefetch-scripts` package.
+
+   - A list of schemes for `mirror://` URLs can be found in [`pkgs/build-support/fetchurl/mirrors.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/fetchurl/mirrors.nix).
+
+   The exact syntax and semantics of the Nix expression language, including the built-in function, are described in the Nix manual in the [chapter on writing Nix expressions](https://hydra.nixos.org/job/nix/trunk/tarball/latest/download-by-type/doc/manual/#chap-writing-nix-expressions).
+
+4. Add a call to the function defined in the previous step to [`pkgs/top-level/all-packages.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/all-packages.nix) with some descriptive name for the variable, e.g. `libfoo`.
+
+   ```ShellSession
+   $ emacs pkgs/top-level/all-packages.nix
+   ```
+
+   The attributes in that file are sorted by category (like “Development / Libraries”) that more-or-less correspond to the directory structure of Nixpkgs, and then by attribute name.
+
+5. To test whether the package builds, run the following command from the root of the nixpkgs source tree:
+
+   ```ShellSession
+   $ nix-build -A libfoo
+   ```
+
+   where `libfoo` should be the variable name defined in the previous step. You may want to add the flag `-K` to keep the temporary build directory in case something fails. If the build succeeds, a symlink `./result` to the package in the Nix store is created.
+
+6. If you want to install the package into your profile (optional), do
+
+   ```ShellSession
+   $ nix-env -f . -iA libfoo
+   ```
+
+7. Optionally commit the new package and open a pull request [to nixpkgs](https://github.com/NixOS/nixpkgs/pulls), or use [the Patches category](https://discourse.nixos.org/t/about-the-patches-category/477) on Discourse for sending a patch without a GitHub account.

doc/contributing/reviewing-contributions.chapter.md

@@ -0,0 +1,208 @@
+# Reviewing contributions {#chap-reviewing-contributions}
+
+::: {.warning}
+The following section is a draft, and the policy for reviewing is still being discussed in issues such as [#11166](https://github.com/NixOS/nixpkgs/issues/11166) and [#20836](https://github.com/NixOS/nixpkgs/issues/20836).
+:::
+
+The Nixpkgs project receives a fairly high number of contributions via GitHub pull requests. Reviewing and approving these is an important task and a way to contribute to the project.
+
+The high change rate of Nixpkgs makes any pull request that remains open for too long subject to conflicts that will require extra work from the submitter or the merger. Reviewing pull requests in a timely manner and being responsive to the comments is the key to avoid this issue. GitHub provides sort filters that can be used to see the [most recently](https://github.com/NixOS/nixpkgs/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-desc) and the [least recently](https://github.com/NixOS/nixpkgs/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-asc) updated pull requests. We highly encourage looking at [this list of ready to merge, unreviewed pull requests](https://github.com/NixOS/nixpkgs/pulls?q=is%3Apr+is%3Aopen+review%3Anone+status%3Asuccess+-label%3A%222.status%3A+work-in-progress%22+no%3Aproject+no%3Aassignee+no%3Amilestone).
+
+When reviewing a pull request, please always be nice and polite. Controversial changes can lead to controversial opinions, but it is important to respect every community member and their work.
+
+GitHub provides reactions as a simple and quick way to provide feedback to pull requests or any comments. The thumb-down reaction should be used with care and if possible accompanied with some explanation so the submitter has directions to improve their contribution.
+
+pull request reviews should include a list of what has been reviewed in a comment, so other reviewers and mergers can know the state of the review.
+
+All the review template samples provided in this section are generic and meant as examples. Their usage is optional and the reviewer is free to adapt them to their liking.
+
+## Package updates {#reviewing-contributions-package-updates}
+
+A package update is the most trivial and common type of pull request. These pull requests mainly consist of updating the version part of the package name and the source hash.
+
+It can happen that non-trivial updates include patches or more complex changes.
+
+Reviewing process:
+
+- Ensure that the package versioning fits the guidelines.
+- Ensure that the commit text fits the guidelines.
+- Ensure that the package maintainers are notified.
+  - [CODEOWNERS](https://help.github.com/articles/about-codeowners) will make GitHub notify users based on the submitted changes, but it can happen that it misses some of the package maintainers.
+- Ensure that the meta field information is correct.
+  - License can change with version updates, so it should be checked to match the upstream license.
+  - If the package has no maintainer, a maintainer must be set. This can be the update submitter or a community member that accepts to take maintainership of the package.
+- Ensure that the code contains no typos.
+- Building the package locally.
+  - pull requests are often targeted to the master or staging branch, and building the pull request locally when it is submitted can trigger many source builds.
+  - It is possible to rebase the changes on nixos-unstable or nixpkgs-unstable for easier review by running the following commands from a nixpkgs clone.
+
+    ```ShellSession
+    $ git fetch origin nixos-unstable
+    $ git fetch origin pull/PRNUMBER/head
+    $ git rebase --onto nixos-unstable BASEBRANCH FETCH_HEAD
+    ```
+
+    - The first command fetches the nixos-unstable branch.
+    - The second command fetches the pull request changes, `PRNUMBER` is the number at the end of the pull request title and `BASEBRANCH` the base branch of the pull request.
+    - The third command rebases the pull request changes to the nixos-unstable branch.
+  - The [nixpkgs-review](https://github.com/Mic92/nixpkgs-review) tool can be used to review a pull request content in a single command. `PRNUMBER` should be replaced by the number at the end of the pull request title. You can also provide the full github pull request url.
+
+    ```ShellSession
+    $ nix-shell -p nixpkgs-review --run "nixpkgs-review pr PRNUMBER"
+    ```
+- Running every binary.
+
+Sample template for a package update review is provided below.
+
+```markdown
+##### Reviewed points
+
+- [ ] package name fits guidelines
+- [ ] package version fits guidelines
+- [ ] package build on ARCHITECTURE
+- [ ] executables tested on ARCHITECTURE
+- [ ] all depending packages build
+
+##### Possible improvements
+
+##### Comments
+```
+
+## New packages {#reviewing-contributions-new-packages}
+
+New packages are a common type of pull requests. These pull requests consists in adding a new nix-expression for a package.
+
+Review process:
+
+- Ensure that the package versioning fits the guidelines.
+- Ensure that the commit name fits the guidelines.
+- Ensure that the meta fields contain correct information.
+  - License must match the upstream license.
+  - Platforms should be set (or the package will not get binary substitutes).
+  - Maintainers must be set. This can be the package submitter or a community member that accepts taking up maintainership of the package.
+- Report detected typos.
+- Ensure the package source:
+  - Uses mirror URLs when available.
+  - Uses the most appropriate functions (e.g. packages from GitHub should use `fetchFromGitHub`).
+- Building the package locally.
+- Running every binary.
+
+Sample template for a new package review is provided below.
+
+```markdown
+##### Reviewed points
+
+- [ ] package path fits guidelines
+- [ ] package name fits guidelines
+- [ ] package version fits guidelines
+- [ ] package build on ARCHITECTURE
+- [ ] executables tested on ARCHITECTURE
+- [ ] `meta.description` is set and fits guidelines
+- [ ] `meta.license` fits upstream license
+- [ ] `meta.platforms` is set
+- [ ] `meta.maintainers` is set
+- [ ] build time only dependencies are declared in `nativeBuildInputs`
+- [ ] source is fetched using the appropriate function
+- [ ] the list of `phases` is not overridden
+- [ ] when a phase (like `installPhase`) is overridden it starts with `runHook preInstall` and ends with `runHook postInstall`.
+- [ ] patches that are remotely available are fetched with `fetchpatch`
+
+##### Possible improvements
+
+##### Comments
+```
+
+## Module updates {#reviewing-contributions-module-updates}
+
+Module updates are submissions changing modules in some ways. These often contains changes to the options or introduce new options.
+
+Reviewing process:
+
+- Ensure that the module maintainers are notified.
+  - [CODEOWNERS](https://help.github.com/articles/about-codeowners/) will make GitHub notify users based on the submitted changes, but it can happen that it misses some of the package maintainers.
+- Ensure that the module tests, if any, are succeeding.
+- Ensure that the introduced options are correct.
+  - Type should be appropriate (string related types differs in their merging capabilities, `loaOf` and `string` types are deprecated).
+  - Description, default and example should be provided.
+- Ensure that option changes are backward compatible.
+  - `mkRenamedOptionModuleWith` provides a way to make option changes backward compatible.
+- Ensure that removed options are declared with `mkRemovedOptionModule`
+- Ensure that changes that are not backward compatible are mentioned in release notes.
+- Ensure that documentations affected by the change is updated.
+
+Sample template for a module update review is provided below.
+
+```markdown
+##### Reviewed points
+
+- [ ] changes are backward compatible
+- [ ] removed options are declared with `mkRemovedOptionModule`
+- [ ] changes that are not backward compatible are documented in release notes
+- [ ] module tests succeed on ARCHITECTURE
+- [ ] options types are appropriate
+- [ ] options description is set
+- [ ] options example is provided
+- [ ] documentation affected by the changes is updated
+
+##### Possible improvements
+
+##### Comments
+```
+
+## New modules {#reviewing-contributions-new-modules}
+
+New modules submissions introduce a new module to NixOS.
+
+Reviewing process:
+
+- Ensure that the module tests, if any, are succeeding.
+- Ensure that the introduced options are correct.
+  - Type should be appropriate (string related types differs in their merging capabilities, `loaOf` and `string` types are deprecated).
+  - Description, default and example should be provided.
+- Ensure that module `meta` field is present
+  - Maintainers should be declared in `meta.maintainers`.
+  - Module documentation should be declared with `meta.doc`.
+- Ensure that the module respect other modules functionality.
+  - For example, enabling a module should not open firewall ports by default.
+
+Sample template for a new module review is provided below.
+
+```markdown
+##### Reviewed points
+
+- [ ] module path fits the guidelines
+- [ ] module tests succeed on ARCHITECTURE
+- [ ] options have appropriate types
+- [ ] options have default
+- [ ] options have example
+- [ ] options have descriptions
+- [ ] No unneeded package is added to environment.systemPackages
+- [ ] meta.maintainers is set
+- [ ] module documentation is declared in meta.doc
+
+##### Possible improvements
+
+##### Comments
+```
+
+## Other submissions {#reviewing-contributions-other-submissions}
+
+Other type of submissions requires different reviewing steps.
+
+If you consider having enough knowledge and experience in a topic and would like to be a long-term reviewer for related submissions, please contact the current reviewers for that topic. They will give you information about the reviewing process. The main reviewers for a topic can be hard to find as there is no list, but checking past pull requests to see who reviewed or git-blaming the code to see who committed to that topic can give some hints.
+
+Container system, boot system and library changes are some examples of the pull requests fitting this category.
+
+## Merging pull requests {#reviewing-contributions--merging-pull-requests}
+
+It is possible for community members that have enough knowledge and experience on a special topic to contribute by merging pull requests.
+
+<!--
+The following paragraphs about how to deal with unactive contributors is just a proposition and should be modified to what the community agrees to be the right policy.
+
+Please note that contributors with commit rights unactive for more than three months will have their commit rights revoked.
+-->
+
+Please see the discussion in [GitHub nixpkgs issue #50105](https://github.com/NixOS/nixpkgs/issues/50105) for information on how to proceed to be granted this level of access.
+
+In a case a contributor definitively leaves the Nix community, they should create an issue or post on [Discourse](https://discourse.nixos.org) with references of packages and modules they maintain so the maintainership can be taken over by other contributors.

doc/contributing/submitting-changes.chapter.md

@@ -0,0 +1,292 @@
+# Submitting changes {#chap-submitting-changes}
+
+## Making patches {#submitting-changes-making-patches}
+
+- Read [Manual (How to write packages for Nix)](https://nixos.org/nixpkgs/manual/).
+
+- Fork [the Nixpkgs repository](https://github.com/nixos/nixpkgs/) on GitHub.
+
+- Create a branch for your future fix.
+
+  - You can make branch from a commit of your local `nixos-version`. That will help you to avoid additional local compilations. Because you will receive packages from binary cache. For example
+
+    ```ShellSession
+    $ nixos-version --hash
+    0998212
+    $ git checkout 0998212
+    $ git checkout -b 'fix/pkg-name-update'
+    ```
+
+  - Please avoid working directly on the `master` branch.
+
+- Make commits of logical units.
+
+- If you removed pkgs or made some major NixOS changes, write about it in the release notes for the next stable release. For example `nixos/doc/manual/release-notes/rl-2003.xml`.
+
+- Check for unnecessary whitespace with `git diff --check` before committing.
+
+- Format the commit in a following way:
+
+  ```
+  (pkg-name | nixos/<module>): (from -> to | init at version | refactor | etc)
+  Additional information.
+  ```
+
+  - Examples:
+    - `nginx: init at 2.0.1`
+    - `firefox: 54.0.1 -> 55.0`
+    - `nixos/hydra: add bazBaz option`
+    - `nixos/nginx: refactor config generation`
+
+- Test your changes. If you work with
+
+  - nixpkgs:
+
+    - update pkg
+      - `nix-env -iA pkg-attribute-name -f <path to your local nixpkgs folder>`
+    - add pkg
+      - Make sure it’s in `pkgs/top-level/all-packages.nix`
+      - `nix-env -iA pkg-attribute-name -f <path to your local nixpkgs folder>`
+    - _If you don’t want to install pkg in you profile_.
+      - `nix-build -A pkg-attribute-name <path to your local nixpkgs folder>` and check results in the folder `result`. It will appear in the same directory where you did `nix-build`.
+    - If you installed your package with `nix-env`, you can run `nix-env -e pkg-name` where `pkg-name` is as reported by `nix-env -q` to uninstall it from your system.
+
+  - NixOS and its modules:
+    - You can add new module to your NixOS configuration file (usually it’s `/etc/nixos/configuration.nix`). And do `sudo nixos-rebuild test -I nixpkgs=<path to your local nixpkgs folder> --fast`.
+
+- If you have commits `pkg-name: oh, forgot to insert whitespace`: squash commits in this case. Use `git rebase -i`.
+
+- [Rebase](https://git-scm.com/book/en/v2/Git-Branching-Rebasing) your branch against current `master`.
+
+## Submitting changes {#submitting-changes-submitting-changes}
+
+- Push your changes to your fork of nixpkgs.
+- Create the pull request
+- Follow [the contribution guidelines](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md#submitting-changes).
+
+## Submitting security fixes {#submitting-changes-submitting-security-fixes}
+
+Security fixes are submitted in the same way as other changes and thus the same guidelines apply.
+
+- If a new version fixing the vulnerability has been released, update the package;
+- If the security fix comes in the form of a patch and a CVE is available, then add the patch to the Nixpkgs tree, and apply it to the package.
+  The name of the patch should be the CVE identifier, so e.g. `CVE-2019-13636.patch`; If a patch is fetched the name needs to be set as well, e.g.:
+
+  ```nix
+  (fetchpatch {
+    name = "CVE-2019-11068.patch";
+    url = "https://gitlab.gnome.org/GNOME/libxslt/commit/e03553605b45c88f0b4b2980adfbbb8f6fca2fd6.patch";
+    sha256 = "0pkpb4837km15zgg6h57bncp66d5lwrlvkr73h0lanywq7zrwhj8";
+  })
+  ```
+
+If a security fix applies to both master and a stable release then, similar to regular changes, they are preferably delivered via master first and cherry-picked to the release branch.
+
+Critical security fixes may by-pass the staging branches and be delivered directly to release branches such as `master` and `release-*`.
+
+## Deprecating/removing packages {#submitting-changes-deprecating-packages}
+
+There is currently no policy when to remove a package.
+
+Before removing a package, one should try to find a new maintainer or fix smaller issues first.
+
+### Steps to remove a package from Nixpkgs {#steps-to-remove-a-package-from-nixpkgs}
+
+We use jbidwatcher as an example for a discontinued project here.
+
+1. Have Nixpkgs checked out locally and up to date.
+1. Create a new branch for your change, e.g. `git checkout -b jbidwatcher`
+1. Remove the actual package including its directory, e.g. `git rm -rf pkgs/applications/misc/jbidwatcher`
+1. Remove the package from the list of all packages (`pkgs/top-level/all-packages.nix`).
+1. Add an alias for the package name in `pkgs/top-level/aliases.nix` (There is also `pkgs/applications/editors/vim/plugins/aliases.nix`. Package sets typically do not have aliases, so we can't add them there.)
+
+    For example in this case:
+
+    ```
+    jbidwatcher = throw "jbidwatcher was discontinued in march 2021"; # added 2021-03-15
+    ```
+
+    The throw message should explain in short why the package was removed for users that still have it installed.
+
+1. Test if the changes introduced any issues by running `nix-env -qaP -f . --show-trace`. It should show the list of packages without errors.
+1. Commit the changes. Explain again why the package was removed. If it was declared discontinued upstream, add a link to the source.
+
+    ```ShellSession
+    $ git add pkgs/applications/misc/jbidwatcher/default.nix pkgs/top-level/all-packages.nix pkgs/top-level/aliases.nix
+    $ git commit
+    ```
+
+    Example commit message:
+
+    ```
+    jbidwatcher: remove
+
+    project was discontinued in march 2021. the program does not work anymore because ebay changed the login.
+
+    https://web.archive.org/web/20210315205723/http://www.jbidwatcher.com/
+    ```
+
+1. Push changes to your GitHub fork with `git push`
+1. Create a pull request against Nixpkgs. Mention the package maintainer.
+
+This is how the pull request looks like in this case: [https://github.com/NixOS/nixpkgs/pull/116470](https://github.com/NixOS/nixpkgs/pull/116470)
+
+## Pull Request Template {#submitting-changes-pull-request-template}
+
+The pull request template helps determine what steps have been made for a contribution so far, and will help guide maintainers on the status of a change. The motivation section of the PR should include any extra details the title does not address and link any existing issues related to the pull request.
+
+When a PR is created, it will be pre-populated with some checkboxes detailed below:
+
+### Tested using sandboxing {#submitting-changes-tested-with-sandbox}
+
+When sandbox builds are enabled, Nix will setup an isolated environment for each build process. It is used to remove further hidden dependencies set by the build environment to improve reproducibility. This includes access to the network during the build outside of `fetch*` functions and files outside the Nix store. Depending on the operating system access to other resources are blocked as well (ex. inter process communication is isolated on Linux); see [sandbox](https://nixos.org/nix/manual/#conf-sandbox) in Nix manual for details.
+
+Sandboxing is not enabled by default in Nix due to a small performance hit on each build. In pull requests for [nixpkgs](https://github.com/NixOS/nixpkgs/) people are asked to test builds with sandboxing enabled (see `Tested using sandboxing` in the pull request template) because in<https://nixos.org/hydra/> sandboxing is also used.
+
+Depending if you use NixOS or other platforms you can use one of the following methods to enable sandboxing **before** building the package:
+
+- **Globally enable sandboxing on NixOS**: add the following to `configuration.nix`
+
+  ```nix
+  nix.useSandbox = true;
+  ```
+
+- **Globally enable sandboxing on non-NixOS platforms**: add the following to: `/etc/nix/nix.conf`
+
+  ```ini
+  sandbox = true
+  ```
+
+### Built on platform(s) {#submitting-changes-platform-diversity}
+
+Many Nix packages are designed to run on multiple platforms. As such, it’s important to let the maintainer know which platforms your changes have been tested on. It’s not always practical to test a change on all platforms, and is not required for a pull request to be merged. Only check the systems you tested the build on in this section.
+
+### Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests) {#submitting-changes-nixos-tests}
+
+Packages with automated tests are much more likely to be merged in a timely fashion because it doesn’t require as much manual testing by the maintainer to verify the functionality of the package. If there are existing tests for the package, they should be run to verify your changes do not break the tests. Tests can only be run on Linux. For more details on writing and running tests, see the [section in the NixOS manual](https://nixos.org/nixos/manual/index.html#sec-nixos-tests).
+
+### Tested compilation of all pkgs that depend on this change using `nixpkgs-review` {#submitting-changes-tested-compilation}
+
+If you are updating a package’s version, you can use nixpkgs-review to make sure all packages that depend on the updated package still compile correctly. The `nixpkgs-review` utility can look for and build all dependencies either based on uncommited changes with the `wip` option or specifying a github pull request number.
+
+review changes from pull request number 12345:
+
+```ShellSession
+nix run nixpkgs.nixpkgs-review -c nixpkgs-review pr 12345
+```
+
+review uncommitted changes:
+
+```ShellSession
+nix run nixpkgs.nixpkgs-review -c nixpkgs-review wip
+```
+
+review changes from last commit:
+
+```ShellSession
+nix run nixpkgs.nixpkgs-review -c nixpkgs-review rev HEAD
+```
+
+### Tested execution of all binary files (usually in `./result/bin/`) {#submitting-changes-tested-execution}
+
+It’s important to test any executables generated by a build when you change or create a package in nixpkgs. This can be done by looking in `./result/bin` and running any files in there, or at a minimum, the main executable for the package. For example, if you make a change to texlive, you probably would only check the binaries associated with the change you made rather than testing all of them.
+
+### Meets Nixpkgs contribution standards {#submitting-changes-contribution-standards}
+
+The last checkbox is fits [CONTRIBUTING.md](https://github.com/NixOS/nixpkgs/blob/master/CONTRIBUTING.md). The contributing document has detailed information on standards the Nix community has for commit messages, reviews, licensing of contributions you make to the project, etc\... Everyone should read and understand the standards the community has for contributing before submitting a pull request.
+
+## Hotfixing pull requests {#submitting-changes-hotfixing-pull-requests}
+
+- Make the appropriate changes in you branch.
+- Don’t create additional commits, do
+  - `git rebase -i`
+  - `git push --force` to your branch.
+
+## Commit policy {#submitting-changes-commit-policy}
+
+- Commits must be sufficiently tested before being merged, both for the master and staging branches.
+- Hydra builds for master and staging should not be used as testing platform, it’s a build farm for changes that have been already tested.
+- When changing the bootloader installation process, extra care must be taken. Grub installations cannot be rolled back, hence changes may break people’s installations forever. For any non-trivial change to the bootloader please file a PR asking for review, especially from \@edolstra.
+
+```{.graphviz caption="Staging workflow"}
+digraph {
+    "small changes" [shape=none]
+    "mass-rebuilds and other large changes" [shape=none]
+    "critical security fixes" [shape=none]
+    "broken staging-next fixes" [shape=none]
+
+    "small changes" -> master
+    "mass-rebuilds and other large changes" -> staging
+    "critical security fixes" -> master
+    "broken staging-next fixes" -> "staging-next"
+
+    "staging-next" -> master [color="#E85EB0"] [label="stabilization ends"] [fontcolor="#E85EB0"]
+    "staging" -> "staging-next" [color="#E85EB0"] [label="stabilization starts"] [fontcolor="#E85EB0"]
+
+    master -> "staging-next" -> staging [color="#5F5EE8"] [label="every six hours (GitHub Action)"] [fontcolor="#5F5EE8"]
+}
+```
+
+[This GitHub Action](https://github.com/NixOS/nixpkgs/blob/master/.github/workflows/periodic-merge-6h.yml) brings changes from `master` to `staging-next` and from `staging-next` to `staging` every 6 hours.
+
+
+### Master branch {#submitting-changes-master-branch}
+
+The `master` branch is the main development branch. It should only see non-breaking commits that do not cause mass rebuilds.
+
+### Staging branch {#submitting-changes-staging-branch}
+
+The `staging` branch is a development branch where mass-rebuilds go. Mass rebuilds are commits that cause rebuilds for many packages, like more than 500 (or perhaps, if it's 'light' packages, 1000). It should only see non-breaking mass-rebuild commits. That means it is not to be used for testing, and changes must have been well tested already. If the branch is already in a broken state, please refrain from adding extra new breakages.
+
+### Staging-next branch {#submitting-changes-staging-next-branch}
+
+The `staging-next` branch is for stabilizing mass-rebuilds submitted to the `staging` branch prior to merging them into `master`. Mass-rebuilds must go via the `staging` branch. It must only see non-breaking commits that are fixing issues blocking it from being merged into the `master ` branch.
+
+If the branch is already in a broken state, please refrain from adding extra new breakages. Stabilize it for a few days and then merge into master.
+
+### Stable release branches {#submitting-changes-stable-release-branches}
+
+The same staging workflow applies to stable release branches, but the main branch is called `release-*` instead of `master`.
+
+Example branch names: `release-21.11`, `staging-21.11`, `staging-next-21.11`.
+
+Most changes added to the stable release branches are cherry-picked (“backported”) from the `master` and staging branches.
+
+#### Automatically backporting a Pull Request {#submitting-changes-stable-release-branches-automatic-backports}
+
+Assign label `backport <branch>` (e.g. `backport release-21.11`) to the PR and a backport PR is automatically created after the PR is merged.
+
+#### Manually backporting changes {#submitting-changes-stable-release-branches-manual-backports}
+
+Cherry-pick changes via `git cherry-pick -x <original commit>` so that the original commit id is included in the commit message.
+
+Add a reason for the backport when it is not obvious from the original commit message. You can do this by cherry picking with `git cherry-pick -xe <original commit>`, which allows editing the commit message. This is not needed for minor version updates that include security and bug fixes but don't add new features or when the commit fixes an otherwise broken package.
+
+Here is an example of a cherry-picked commit message with good reason description:
+
+```
+zfs: Keep trying root import until it works
+
+Works around #11003.
+
+(cherry picked from commit 98b213a11041af39b39473906b595290e2a4e2f9)
+
+Reason: several people cannot boot with ZFS on NVMe
+```
+
+Other examples of reasons are:
+
+- Previously the build would fail due to, e.g., `getaddrinfo` not being defined
+- The previous download links were all broken
+- Crash when starting on some X11 systems
+
+#### Acceptable backport criteria
+
+The stable branch does have some changes which cannot be backported. Most notable are breaking changes. The desire is to have stable users be uninterrupted when updating packages.
+
+However, many changes are able to be backported, including:
+- New Packages / Modules
+- Security / Patch updates
+- Version updates which include new functionality (but no breaking changes)
+- Services which require a client to be up-to-date regardless. (E.g. `spotify`, `steam`, or `discord`)
+- Security critical applications (E.g. `firefox`)

doc/contributing/vulnerability-roundup.chapter.md

@@ -0,0 +1,45 @@
+# Vulnerability Roundup {#chap-vulnerability-roundup}
+
+## Issues {#vulnerability-roundup-issues}
+
+Vulnerable packages in Nixpkgs are managed using issues.
+Currently opened ones can be found using the following:
+
+[github.com/NixOS/nixpkgs/issues?q=is:issue+is:open+"Vulnerability+roundup"](https://github.com/NixOS/nixpkgs/issues?q=is%3Aissue+is%3Aopen+%22Vulnerability+roundup%22)
+
+Each issue correspond to a vulnerable version of a package; As a consequence:
+
+- One issue can contain several CVEs;
+- One CVE can be shared across several issues;
+- A single package can be concerned by several issues.
+
+
+A "Vulnerability roundup" issue usually respects the following format:
+
+```txt
+<link to relevant package search on search.nix.gsc.io>, <link to relevant files in Nixpkgs on GitHub>
+
+<list of related CVEs, their CVSS score, and the impacted NixOS version>
+
+<list of the scanned Nixpkgs versions>
+
+<list of relevant contributors>
+```
+
+Note that there can be an extra comment containing links to previously reported (and still open) issues for the same package.
+
+
+## Triaging and Fixing {#vulnerability-roundup-triaging-and-fixing}
+
+**Note**: An issue can be a "false positive" (i.e. automatically opened, but without the package it refers to being actually vulnerable).
+If you find such a "false positive", comment on the issue an explanation of why it falls into this category, linking as much information as the necessary to help maintainers double check.
+
+If you are investigating a "true positive":
+
+- Find the earliest patched version or a code patch in the CVE details;
+- Is the issue already patched (version up-to-date or patch applied manually) in Nixpkgs's `master` branch?
+  - **No**:
+    - [Submit a security fix](#submitting-changes-submitting-security-fixes);
+    - Once the fix is merged into `master`, [submit the change to the vulnerable release branch(es)](https://nixos.org/manual/nixpkgs/stable/#submitting-changes-stable-release-branches);
+  - **Yes**: [Backport the change to the vulnerable release branch(es)](https://nixos.org/manual/nixpkgs/stable/#submitting-changes-stable-release-branches).
+- When the patch has made it into all the relevant branches (`master`, and the vulnerable releases), close the relevant issue(s).

doc/default.nix

@@ -0,0 +1,39 @@
+{ pkgs ? (import ./.. { }), nixpkgs ? { }}:
+let
+  lib = pkgs.lib;
+  doc-support = import ./doc-support { inherit pkgs nixpkgs; };
+in pkgs.stdenv.mkDerivation {
+  name = "nixpkgs-manual";
+
+  nativeBuildInputs = with pkgs; [
+    pandoc
+    graphviz
+    libxml2
+    libxslt
+    zip
+    jing
+    xmlformat
+  ];
+
+  src = lib.cleanSource ./.;
+
+  postPatch = ''
+    ln -s ${doc-support} ./doc-support/result
+  '';
+
+  installPhase = ''
+    dest="$out/share/doc/nixpkgs"
+    mkdir -p "$(dirname "$dest")"
+    mv out/html "$dest"
+    mv "$dest/index.html" "$dest/manual.html"
+
+    mv out/epub/manual.epub "$dest/nixpkgs-manual.epub"
+
+    mkdir -p $out/nix-support/
+    echo "doc manual $dest manual.html" >> $out/nix-support/hydra-build-products
+    echo "doc manual $dest nixpkgs-manual.epub" >> $out/nix-support/hydra-build-products
+  '';
+
+  # Environment variables
+  PANDOC_LUA_FILTERS_DIR = "${pkgs.pandoc-lua-filters}/share/pandoc/filters";
+}

doc/doc-support/default.nix

@@ -0,0 +1,54 @@
+{ pkgs ? (import ../.. {}), nixpkgs ? { }}:
+let
+  locationsXml = import ./lib-function-locations.nix { inherit pkgs nixpkgs; };
+  functionDocs = import ./lib-function-docs.nix { inherit locationsXml pkgs; };
+  version = pkgs.lib.version;
+
+  epub-xsl = pkgs.writeText "epub.xsl" ''
+    <?xml version='1.0'?>
+    <xsl:stylesheet
+      xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+      version="1.0">
+      <xsl:import href="${pkgs.docbook_xsl_ns}/xml/xsl/docbook/epub/docbook.xsl" />
+      <xsl:import href="${./parameters.xml}"/>
+    </xsl:stylesheet>
+  '';
+
+  xhtml-xsl = pkgs.writeText "xhtml.xsl" ''
+    <?xml version='1.0'?>
+    <xsl:stylesheet
+      xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+      version="1.0">
+      <xsl:import href="${pkgs.docbook_xsl_ns}/xml/xsl/docbook/xhtml/docbook.xsl" />
+      <xsl:import href="${./parameters.xml}"/>
+    </xsl:stylesheet>
+  '';
+
+  # NB: This file describes the Nixpkgs manual, which happens to use module
+  #     docs infra originally developed for NixOS.
+  optionsDoc = pkgs.nixosOptionsDoc {
+    inherit (pkgs.lib.evalModules { modules = [ ../../pkgs/top-level/config.nix ]; }) options;
+    documentType = "none";
+  };
+
+in pkgs.runCommand "doc-support" {}
+''
+  mkdir result
+  (
+    cd result
+    ln -s ${locationsXml} ./function-locations.xml
+    ln -s ${functionDocs} ./function-docs
+    ln -s ${optionsDoc.optionsDocBook} ./config-options.docbook.xml
+
+    ln -s ${pkgs.docbook5}/xml/rng/docbook/docbook.rng ./docbook.rng
+    ln -s ${pkgs.docbook_xsl_ns}/xml/xsl ./xsl
+    ln -s ${epub-xsl} ./epub.xsl
+    ln -s ${xhtml-xsl} ./xhtml.xsl
+
+    ln -s ${../../nixos/doc/xmlformat.conf} ./xmlformat.conf
+    ln -s ${pkgs.documentation-highlighter} ./highlightjs
+
+    echo -n "${version}" > ./version
+  )
+  mv result $out
+''

doc/doc-support/lib-function-docs.nix

@@ -0,0 +1,27 @@
+# Generates the documentation for library functons via nixdoc. To add
+# another library function file to this list, the include list in the
+# file `doc/functions/library.xml` must also be updated.
+
+{ pkgs ? import ./.. {}, locationsXml }:
+
+with pkgs; stdenv.mkDerivation {
+  name = "nixpkgs-lib-docs";
+  src = ./../../lib;
+
+  buildInputs = [ nixdoc ];
+  installPhase = ''
+    function docgen {
+      nixdoc -c "$1" -d "$2" -f "../lib/$1.nix"  > "$out/$1.xml"
+    }
+
+    mkdir -p $out
+    ln -s ${locationsXml} $out/locations.xml
+
+    docgen strings 'String manipulation functions'
+    docgen trivial 'Miscellaneous functions'
+    docgen lists 'List manipulation functions'
+    docgen debug 'Debugging functions'
+    docgen options 'NixOS / nixpkgs option handling'
+    docgen sources 'Source filtering functions'
+  '';
+}

doc/doc-support/lib-function-locations.nix

@@ -0,0 +1,85 @@
+{ pkgs ? (import ./.. { }), nixpkgs ? { }}:
+let
+  revision = pkgs.lib.trivial.revisionWithDefault (nixpkgs.revision or "master");
+
+  libDefPos = set:
+    builtins.map
+      (name: {
+        name = name;
+        location = builtins.unsafeGetAttrPos name set;
+      })
+      (builtins.attrNames set);
+
+  libset = toplib:
+    builtins.map
+      (subsetname: {
+        subsetname = subsetname;
+        functions = libDefPos toplib.${subsetname};
+      })
+      (builtins.filter
+        (name: builtins.isAttrs toplib.${name})
+        (builtins.attrNames toplib));
+
+  nixpkgsLib = pkgs.lib;
+
+  flattenedLibSubset = { subsetname, functions }:
+  builtins.map
+    (fn: {
+      name = "lib.${subsetname}.${fn.name}";
+      value = fn.location;
+    })
+    functions;
+
+  locatedlibsets = libs: builtins.map flattenedLibSubset (libset libs);
+  removeFilenamePrefix = prefix: filename:
+    let
+    prefixLen = (builtins.stringLength prefix) + 1; # +1 to remove the leading /
+      filenameLen = builtins.stringLength filename;
+      substr = builtins.substring prefixLen filenameLen filename;
+      in substr;
+
+  removeNixpkgs = removeFilenamePrefix (builtins.toString pkgs.path);
+
+  liblocations =
+    builtins.filter
+      (elem: elem.value != null)
+      (nixpkgsLib.lists.flatten
+        (locatedlibsets nixpkgsLib));
+
+  fnLocationRelative = { name, value }:
+    {
+      inherit name;
+      value = value // { file = removeNixpkgs value.file; };
+    };
+
+  relativeLocs = (builtins.map fnLocationRelative liblocations);
+  sanitizeId = builtins.replaceStrings
+    [ "'"      ]
+    [ "-prime" ];
+
+  urlPrefix = "https://github.com/NixOS/nixpkgs/blob/${revision}";
+  xmlstrings = (nixpkgsLib.strings.concatMapStrings
+      ({ name, value }:
+      ''
+      <section><title>${name}</title>
+        <para xml:id="${sanitizeId name}">
+        Located at
+        <link
+          xlink:href="${urlPrefix}/${value.file}#L${builtins.toString value.line}">${value.file}:${builtins.toString value.line}</link>
+        in  <literal>&lt;nixpkgs&gt;</literal>.
+        </para>
+        </section>
+      '')
+      relativeLocs);
+
+in pkgs.writeText
+    "locations.xml"
+    ''
+    <section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         version="5">
+         <title>All the locations for every lib function</title>
+         <para>This file is only for inclusion by other files.</para>
+         ${xmlstrings}
+    </section>
+    ''

doc/doc-support/parameters.xml

@@ -0,0 +1,14 @@
+<?xml version='1.0'?>
+<xsl:stylesheet
+    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+    version="1.0">
+ <xsl:param name="section.autolabel" select="1" />
+ <xsl:param name="section.label.includes.component.label" select="1" />
+ <xsl:param name="html.stylesheet" select="'style.css overrides.css highlightjs/mono-blue.css'" />
+ <xsl:param name="html.script" select="'./highlightjs/highlight.pack.js ./highlightjs/loader.js'" />
+ <xsl:param name="xref.with.number.and.title" select="1" />
+ <xsl:param name="use.id.as.filename" select="1" />
+ <xsl:param name="toc.section.depth" select="0" />
+ <xsl:param name="admon.style" select="''" />
+ <xsl:param name="callout.graphics.extension" select="'.svg'" />
+</xsl:stylesheet>

doc/functions.xml

@@ -0,0 +1,14 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-functions">
+ <title>Functions reference</title>
+ <para>
+  The nixpkgs repository has several utility functions to manipulate Nix expressions.
+ </para>
+ <xi:include href="functions/library.xml" />
+ <xi:include href="functions/generators.section.xml" />
+ <xi:include href="functions/debug.section.xml" />
+ <xi:include href="functions/prefer-remote-fetch.section.xml" />
+ <xi:include href="functions/nix-gitignore.section.xml" />
+</chapter>

doc/functions/debug.section.md

@@ -0,0 +1,5 @@
+# Debugging Nix Expressions {#sec-debug}
+
+Nix is a unityped, dynamic language, this means every value can potentially appear anywhere. Since it is also non-strict, evaluation order and what ultimately is evaluated might surprise you. Therefore it is important to be able to debug nix expressions.
+
+In the `lib/debug.nix` file you will find a number of functions that help (pretty-)printing values while evaluation is running. You can even specify how deep these values should be printed recursively, and transform them on the fly. Please consult the docstrings in `lib/debug.nix` for usage information.

doc/functions/generators.section.md

@@ -0,0 +1,56 @@
+# Generators {#sec-generators}
+Generators are functions that create file formats from nix data structures, e. g. for configuration files. There are generators available for: `INI`, `JSON` and `YAML`
+
+All generators follow a similar call interface: `generatorName configFunctions data`, where `configFunctions` is an attrset of user-defined functions that format nested parts of the content. They each have common defaults, so often they do not need to be set manually. An example is `mkSectionName ? (name: libStr.escape [ "[" "]" ] name)` from the `INI` generator. It receives the name of a section and sanitizes it. The default `mkSectionName` escapes `[` and `]` with a backslash.
+
+Generators can be fine-tuned to produce exactly the file format required by your application/service. One example is an INI-file format which uses `: ` as separator, the strings `"yes"`/`"no"` as boolean values and requires all string values to be quoted:
+
+```nix
+with lib;
+let
+  customToINI = generators.toINI {
+    # specifies how to format a key/value pair
+    mkKeyValue = generators.mkKeyValueDefault {
+      # specifies the generated string for a subset of nix values
+      mkValueString = v:
+             if v == true then ''"yes"''
+        else if v == false then ''"no"''
+        else if isString v then ''"${v}"''
+        # and delegats all other values to the default generator
+        else generators.mkValueStringDefault {} v;
+    } ":";
+  };
+
+# the INI file can now be given as plain old nix values
+in customToINI {
+  main = {
+    pushinfo = true;
+    autopush = false;
+    host = "localhost";
+    port = 42;
+  };
+  mergetool = {
+    merge = "diff3";
+  };
+}
+```
+
+This will produce the following INI file as nix string:
+
+```INI
+[main]
+autopush:"no"
+host:"localhost"
+port:42
+pushinfo:"yes"
+str\:ange:"very::strange"
+
+[mergetool]
+merge:"diff3"
+```
+
+::: {.note}
+Nix store paths can be converted to strings by enclosing a derivation attribute like so: `"${drv}"`.
+:::
+
+Detailed documentation for each generator can be found in `lib/generators.nix`.

doc/functions/library.xml

@@ -0,0 +1,30 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-functions-library">
+ <title>Nixpkgs Library Functions</title>
+
+ <para>
+  Nixpkgs provides a standard library at <varname>pkgs.lib</varname>, or through <code>import &lt;nixpkgs/lib&gt;</code>.
+ </para>
+
+ <xi:include href="./library/asserts.xml" />
+
+ <xi:include href="./library/attrsets.xml" />
+
+<!-- These docs are generated via nixdoc. To add another generated
+      library function file to this list, the file
+      `lib-function-docs.nix` must also be updated. -->
+
+ <xi:include href="./library/generated/strings.xml" />
+
+ <xi:include href="./library/generated/trivial.xml" />
+
+ <xi:include href="./library/generated/lists.xml" />
+
+ <xi:include href="./library/generated/debug.xml" />
+
+ <xi:include href="./library/generated/options.xml" />
+
+ <xi:include href="./library/generated/sources.xml" />
+</section>

doc/functions/library/asserts.xml

@@ -0,0 +1,112 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="sec-functions-library-asserts">
+ <title>Assert functions</title>
+
+ <section xml:id="function-library-lib.asserts.assertMsg">
+  <title><function>lib.asserts.assertMsg</function></title>
+
+  <subtitle><literal>assertMsg :: Bool -> String -> Bool</literal>
+  </subtitle>
+
+  <xi:include href="./locations.xml" xpointer="lib.asserts.assertMsg" />
+
+  <para>
+   Print a trace message if <literal>pred</literal> is false.
+  </para>
+
+  <para>
+   Intended to be used to augment asserts with helpful error messages.
+  </para>
+
+  <variablelist>
+   <varlistentry>
+    <term>
+     <varname>pred</varname>
+    </term>
+    <listitem>
+     <para>
+      Condition under which the <varname>msg</varname> should <emphasis>not</emphasis> be printed.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>msg</varname>
+    </term>
+    <listitem>
+     <para>
+      Message to print.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+
+  <example xml:id="function-library-lib.asserts.assertMsg-example-false">
+   <title>Printing when the predicate is false</title>
+<programlisting><![CDATA[
+assert lib.asserts.assertMsg ("foo" == "bar") "foo is not bar, silly"
+stderr> trace: foo is not bar, silly
+stderr> assert failed
+]]></programlisting>
+  </example>
+ </section>
+
+ <section xml:id="function-library-lib.asserts.assertOneOf">
+  <title><function>lib.asserts.assertOneOf</function></title>
+
+  <subtitle><literal>assertOneOf :: String -> String ->
+      StringList -> Bool</literal>
+  </subtitle>
+
+  <xi:include href="./locations.xml" xpointer="lib.asserts.assertOneOf" />
+
+  <para>
+   Specialized <function>asserts.assertMsg</function> for checking if <varname>val</varname> is one of the elements of <varname>xs</varname>. Useful for checking enums.
+  </para>
+
+  <variablelist>
+   <varlistentry>
+    <term>
+     <varname>name</varname>
+    </term>
+    <listitem>
+     <para>
+      The name of the variable the user entered <varname>val</varname> into, for inclusion in the error message.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>val</varname>
+    </term>
+    <listitem>
+     <para>
+      The value of what the user provided, to be compared against the values in <varname>xs</varname>.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>xs</varname>
+    </term>
+    <listitem>
+     <para>
+      The list of valid values.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+
+  <example xml:id="function-library-lib.asserts.assertOneOf-example">
+   <title>Ensuring a user provided a possible value</title>
+<programlisting><![CDATA[
+let sslLibrary = "bearssl";
+in lib.asserts.assertOneOf "sslLibrary" sslLibrary [ "openssl" "libressl" ];
+=> false
+stderr> trace: sslLibrary must be one of "openssl", "libressl", but is: "bearssl"
+        ]]></programlisting>
+  </example>
+ </section>
+</section>

doc/functions/nix-gitignore.section.md

@@ -0,0 +1,49 @@
+# pkgs.nix-gitignore {#sec-pkgs-nix-gitignore}
+
+`pkgs.nix-gitignore` is a function that acts similarly to `builtins.filterSource` but also allows filtering with the help of the gitignore format.
+
+## Usage {#sec-pkgs-nix-gitignore-usage}
+
+`pkgs.nix-gitignore` exports a number of functions, but you\'ll most likely need either `gitignoreSource` or `gitignoreSourcePure`. As their first argument, they both accept either 1. a file with gitignore lines or 2. a string with gitignore lines, or 3. a list of either of the two. They will be concatenated into a single big string.
+
+```nix
+{ pkgs ? import <nixpkgs> {} }:
+
+ nix-gitignore.gitignoreSource [] ./source
+     # Simplest version
+
+ nix-gitignore.gitignoreSource "supplemental-ignores\n" ./source
+     # This one reads the ./source/.gitignore and concats the auxiliary ignores
+
+ nix-gitignore.gitignoreSourcePure "ignore-this\nignore-that\n" ./source
+     # Use this string as gitignore, don't read ./source/.gitignore.
+
+ nix-gitignore.gitignoreSourcePure ["ignore-this\nignore-that\n", ~/.gitignore] ./source
+     # It also accepts a list (of strings and paths) that will be concatenated
+     # once the paths are turned to strings via readFile.
+```
+
+These functions are derived from the `Filter` functions by setting the first filter argument to `(_: _: true)`:
+
+```nix
+gitignoreSourcePure = gitignoreFilterSourcePure (_: _: true);
+gitignoreSource = gitignoreFilterSource (_: _: true);
+```
+
+Those filter functions accept the same arguments the `builtins.filterSource` function would pass to its filters, thus `fn: gitignoreFilterSourcePure fn ""` should be extensionally equivalent to `filterSource`. The file is blacklisted if it\'s blacklisted by either your filter or the gitignoreFilter.
+
+If you want to make your own filter from scratch, you may use
+
+```nix
+gitignoreFilter = ign: root: filterPattern (gitignoreToPatterns ign) root;
+```
+
+## gitignore files in subdirectories {#sec-pkgs-nix-gitignore-usage-recursive}
+
+If you wish to use a filter that would search for .gitignore files in subdirectories, just like git does by default, use this function:
+
+```nix
+gitignoreFilterRecursiveSource = filter: patterns: root:
+# OR
+gitignoreRecursiveSource = gitignoreFilterSourcePure (_: _: true);
+```

doc/functions/prefer-remote-fetch.section.md

@@ -0,0 +1,17 @@
+# prefer-remote-fetch overlay {#sec-prefer-remote-fetch}
+
+`prefer-remote-fetch` is an overlay that download sources on remote builder. This is useful when the evaluating machine has a slow upload while the builder can fetch faster directly from the source. To use it, put the following snippet as a new overlay:
+
+```nix
+self: super:
+  (super.prefer-remote-fetch self super)
+```
+
+A full configuration example for that sets the overlay up for your own account, could look like this
+
+```ShellSession
+$ mkdir ~/.config/nixpkgs/overlays/
+$ cat > ~/.config/nixpkgs/overlays/prefer-remote-fetch.nix <<EOF
+  self: super: super.prefer-remote-fetch self super
+EOF
+```

doc/hooks/index.xml

@@ -0,0 +1,10 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-hooks">
+ <title>Hooks reference</title>
+ <para>
+  Nixpkgs has several hook packages that augment the stdenv phases.
+ </para>
+ <xi:include href="./postgresql-test-hook.section.xml" />
+</chapter>

doc/hooks/postgresql-test-hook.section.md

@@ -0,0 +1,59 @@
+
+# `postgresqlTestHook` {#sec-postgresqlTestHook}
+
+This hook starts a PostgreSQL server during the `checkPhase`. Example:
+
+```nix
+{ stdenv, postgresql, postgresqlTestHook }:
+stdenv.mkDerivation {
+
+  # ...
+
+  checkInputs = [
+    postgresql
+    postgresqlTestHook
+  ];
+}
+```
+
+If you use a custom `checkPhase`, remember to add the `runHook` calls:
+```nix
+  checkPhase ''
+    runHook preCheck
+
+    # ... your tests
+
+    runHook postCheck
+  ''
+```
+
+## Variables {#sec-postgresqlTestHook-variables}
+
+The hook logic will read a number of variables and set them to a default value if unset or empty.
+
+Exported variables:
+
+ - `PGDATA`: location of server files.
+ - `PGHOST`: location of UNIX domain socket directory; the default `host` in a connection string.
+ - `PGUSER`: user to create / log in with, default: `test_user`.
+ - `PGDATABASE`: database name, default: `test_db`.
+
+Bash-only variables:
+
+ - `postgresqlTestUserOptions`: SQL options to use when creating the `$PGUSER` role, default: `LOGIN`.
+ - `postgresqlTestSetupSQL`: SQL commands to run as database administrator after startup, default: statements that create `$PGUSER` and `$PGDATABASE`.
+ - `postgresqlTestSetupCommands`: bash commands to run after database start, defaults to running `$postgresqlTestSetupSQL` as database administrator.
+ - `postgresqlEnableTCP`: set to `1` to enable TCP listening. Flaky; not recommended.
+ - `postgresqlStartCommands`: defaults to `pg_ctl start`.
+
+## TCP and the Nix sandbox {#sec-postgresqlTestHook-tcp}
+
+`postgresqlEnableTCP` relies on network sandboxing, which is not available on macOS and some custom Nix installations, resulting in flaky tests.
+For this reason, it is disabled by default.
+
+The preferred solution is to make the test suite use a UNIX domain socket connection. This is the default behavior when no `host` connection parameter is provided.
+Some test suites hardcode a value for `host` though, so a patch may be required. If you can upstream the patch, you can make `host` default to the `PGHOST` environment variable when set. Otherwise, you can patch it locally to omit the `host` connection string parameter altogether.
+
+::: {.note}
+The error `libpq: failed (could not receive data from server: Connection refused` is generally an indication that the test suite is trying to connect through TCP.
+:::

doc/languages-frameworks/agda.section.md

@@ -0,0 +1,256 @@
+# Agda {#agda}
+
+## How to use Agda {#how-to-use-agda}
+
+Agda is available as the [agda](https://search.nixos.org/packages?channel=unstable&show=agda&from=0&size=30&sort=relevance&query=agda)
+package.
+
+The `agda` package installs an Agda-wrapper, which calls `agda` with `--library-file`
+set to a generated library-file within the nix store, this means your library-file in
+`$HOME/.agda/libraries` will be ignored. By default the agda package installs Agda
+with no libraries, i.e. the generated library-file is empty. To use Agda with libraries,
+the `agda.withPackages` function can be used. This function either takes:
+
+* A list of packages,
+* or a function which returns a list of packages when given the `agdaPackages` attribute set,
+* or an attribute set containing a list of packages and a GHC derivation for compilation (see below).
+* or an attribute set containing a function which returns a list of packages when given the `agdaPackages` attribute set and a GHC derivation for compilation (see below).
+
+For example, suppose we wanted a version of Agda which has access to the standard library. This can be obtained with the expressions:
+
+```nix
+agda.withPackages [ agdaPackages.standard-library ]
+```
+
+or
+
+```nix
+agda.withPackages (p: [ p.standard-library ])
+```
+
+or can be called as in the [Compiling Agda](#compiling-agda) section.
+
+If you want to use a different version of a library (for instance a development version)
+override the `src` attribute of the package to point to your local repository
+
+```nix
+agda.withPackages (p: [
+  (p.standard-library.overrideAttrs (oldAttrs: {
+    version = "local version";
+    src = /path/to/local/repo/agda-stdlib;
+  }))
+])
+```
+
+You can also reference a GitHub repository
+
+```nix
+agda.withPackages (p: [
+  (p.standard-library.overrideAttrs (oldAttrs: {
+    version = "1.5";
+    src =  fetchFromGitHub {
+      repo = "agda-stdlib";
+      owner = "agda";
+      rev = "v1.5";
+      sha256 = "16fcb7ssj6kj687a042afaa2gq48rc8abihpm14k684ncihb2k4w";
+    };
+  }))
+])
+```
+
+If you want to use a library not added to Nixpkgs, you can add a
+dependency to a local library by calling `agdaPackages.mkDerivation`.
+
+```nix
+agda.withPackages (p: [
+  (p.mkDerivation {
+    pname = "your-agda-lib";
+    version = "1.0.0";
+    src = /path/to/your-agda-lib;
+  })
+])
+```
+
+Again you can reference GitHub
+
+```nix
+agda.withPackages (p: [
+  (p.mkDerivation {
+    pname = "your-agda-lib";
+    version = "1.0.0";
+    src = fetchFromGitHub {
+      repo = "repo";
+      owner = "owner";
+      version = "...";
+      rev = "...";
+      sha256 = "...";
+    };
+  })
+])
+```
+
+See [Building Agda Packages](#building-agda-packages) for more information on `mkDerivation`.
+
+Agda will not by default use these libraries. To tell Agda to use a library we have some options:
+
+* Call `agda` with the library flag:
+  ```ShellSession
+  $ agda -l standard-library -i . MyFile.agda
+  ```
+* Write a `my-library.agda-lib` file for the project you are working on which may look like:
+  ```
+  name: my-library
+  include: .
+  depend: standard-library
+  ```
+* Create the file `~/.agda/defaults` and add any libraries you want to use by default.
+
+More information can be found in the [official Agda documentation on library management](https://agda.readthedocs.io/en/v2.6.1/tools/package-system.html).
+
+## Compiling Agda {#compiling-agda}
+
+Agda modules can be compiled using the GHC backend with the `--compile` flag. A version of `ghc` with `ieee754` is made available to the Agda program via the `--with-compiler` flag.
+This can be overridden by a different version of `ghc` as follows:
+
+```nix
+agda.withPackages {
+  pkgs = [ ... ];
+  ghc = haskell.compiler.ghcHEAD;
+}
+```
+
+## Writing Agda packages {#writing-agda-packages}
+
+To write a nix derivation for an Agda library, first check that the library has a `*.agda-lib` file.
+
+A derivation can then be written using `agdaPackages.mkDerivation`. This has similar arguments to `stdenv.mkDerivation` with the following additions:
+
+* `everythingFile` can be used to specify the location of the `Everything.agda` file, defaulting to `./Everything.agda`. If this file does not exist then either it should be patched in or the `buildPhase` should be overridden (see below).
+* `libraryName` should be the name that appears in the `*.agda-lib` file, defaulting to `pname`.
+* `libraryFile` should be the file name of the `*.agda-lib` file, defaulting to `${libraryName}.agda-lib`.
+
+Here is an example `default.nix`
+
+```nix
+{ nixpkgs ?  <nixpkgs> }:
+with (import nixpkgs {});
+agdaPackages.mkDerivation {
+  version = "1.0";
+  pname = "my-agda-lib";
+  src = ./.;
+  buildInputs = [
+    agdaPackages.standard-library
+  ];
+}
+```
+
+### Building Agda packages {#building-agda-packages}
+
+The default build phase for `agdaPackages.mkDerivation` simply runs `agda` on the `Everything.agda` file.
+If something else is needed to build the package (e.g. `make`) then the `buildPhase` should be overridden.
+Additionally, a `preBuild` or `configurePhase` can be used if there are steps that need to be done prior to checking the `Everything.agda` file.
+`agda` and the Agda libraries contained in `buildInputs` are made available during the build phase.
+
+### Installing Agda packages {#installing-agda-packages}
+
+The default install phase copies Agda source files, Agda interface files (`*.agdai`) and `*.agda-lib` files to the output directory.
+This can be overridden.
+
+By default, Agda sources are files ending on `.agda`, or literate Agda files ending on `.lagda`, `.lagda.tex`, `.lagda.org`, `.lagda.md`, `.lagda.rst`. The list of recognised Agda source extensions can be extended by setting the `extraExtensions` config variable.
+
+## Maintaining the Agda package set on Nixpkgs {#maintaining-the-agda-package-set-on-nixpkgs}
+
+We are aiming at providing all common Agda libraries as packages on `nixpkgs`,
+and keeping them up to date.
+Contributions and maintenance help is always appreciated,
+but the maintenance effort is typically low since the Agda ecosystem is quite small.
+
+The `nixpkgs` Agda package set tries to take up a role similar to that of [Stackage](https://www.stackage.org/) in the Haskell world.
+It is a curated set of libraries that:
+
+1. Always work together.
+2. Are as up-to-date as possible.
+
+While the Haskell ecosystem is huge, and Stackage is highly automatised,
+the Agda package set is small and can (still) be maintained by hand.
+
+### Adding Agda packages to Nixpkgs {#adding-agda-packages-to-nixpkgs}
+
+To add an Agda package to `nixpkgs`, the derivation should be written to `pkgs/development/libraries/agda/${library-name}/` and an entry should be added to `pkgs/top-level/agda-packages.nix`. Here it is called in a scope with access to all other Agda libraries, so the top line of the `default.nix` can look like:
+
+```nix
+{ mkDerivation, standard-library, fetchFromGitHub }:
+```
+
+Note that the derivation function is called with `mkDerivation` set to `agdaPackages.mkDerivation`, therefore you
+could use a similar set as in your `default.nix` from [Writing Agda Packages](#writing-agda-packages) with
+`agdaPackages.mkDerivation` replaced with `mkDerivation`.
+
+Here is an example skeleton derivation for iowa-stdlib:
+
+```nix
+mkDerivation {
+  version = "1.5.0";
+  pname = "iowa-stdlib";
+
+  src = ...
+
+  libraryFile = "";
+  libraryName = "IAL-1.3";
+
+  buildPhase = ''
+    patchShebangs find-deps.sh
+    make
+  '';
+}
+```
+
+This library has a file called `.agda-lib`, and so we give an empty string to `libraryFile` as nothing precedes `.agda-lib` in the filename. This file contains `name: IAL-1.3`, and so we let `libraryName =  "IAL-1.3"`. This library does not use an `Everything.agda` file and instead has a Makefile, so there is no need to set `everythingFile` and we set a custom `buildPhase`.
+
+When writing an Agda package it is essential to make sure that no `.agda-lib` file gets added to the store as a single file (for example by using `writeText`). This causes Agda to think that the nix store is a Agda library and it will attempt to write to it whenever it typechecks something. See [https://github.com/agda/agda/issues/4613](https://github.com/agda/agda/issues/4613).
+
+In the pull request adding this library,
+you can test whether it builds correctly by writing in a comment:
+
+```
+@ofborg build agdaPackages.iowa-stdlib
+```
+
+### Maintaining Agda packages
+
+As mentioned before, the aim is to have a compatible, and up-to-date package set.
+These two conditions sometimes exclude each other:
+For example, if we update `agdaPackages.standard-library` because there was an upstream release,
+this will typically break many reverse dependencies,
+i.e. downstream Agda libraries that depend on the standard library.
+In `nixpkgs` we are typically among the first to notice this,
+since we have build tests in place to check this.
+
+In a pull request updating e.g. the standard library, you should write the following comment:
+
+```
+@ofborg build agdaPackages.standard-library.passthru.tests
+```
+
+This will build all reverse dependencies of the standard library,
+for example `agdaPackages.agda-categories`, or `agdaPackages.generic`.
+
+In some cases it is useful to build _all_ Agda packages.
+This can be done with the following Github comment:
+
+```
+@ofborg build agda.passthru.tests.allPackages
+```
+
+Sometimes, the builds of the reverse dependencies fail because they have not yet been updated and released.
+You should drop the maintainers a quick issue notifying them of the breakage,
+citing the build error (which you can get from the ofborg logs).
+If you are motivated, you might even send a pull request that fixes it.
+Usually, the maintainers will answer within a week or two with a new release.
+Bumping the version of that reverse dependency should be a further commit on your PR.
+
+In the rare case that a new release is not to be expected within an acceptable time,
+simply mark the broken package as broken by setting `meta.broken = true;`.
+This will exclude it from the build test.
+It can be added later when it is fixed,
+and does not hinder the advancement of the whole package set in the meantime.

doc/languages-frameworks/android.section.md

@@ -0,0 +1,346 @@
+# Android {#android}
+
+The Android build environment provides three major features and a number of
+supporting features.
+
+## Deploying an Android SDK installation with plugins {#deploying-an-android-sdk-installation-with-plugins}
+
+The first use case is deploying the SDK with a desired set of plugins or subsets
+of an SDK.
+
+```nix
+with import <nixpkgs> {};
+
+let
+  androidComposition = androidenv.composeAndroidPackages {
+    toolsVersion = "26.1.1";
+    platformToolsVersion = "30.0.5";
+    buildToolsVersions = [ "30.0.3" ];
+    includeEmulator = false;
+    emulatorVersion = "30.3.4";
+    platformVersions = [ "28" "29" "30" ];
+    includeSources = false;
+    includeSystemImages = false;
+    systemImageTypes = [ "google_apis_playstore" ];
+    abiVersions = [ "armeabi-v7a" "arm64-v8a" ];
+    cmakeVersions = [ "3.10.2" ];
+    includeNDK = true;
+    ndkVersions = ["22.0.7026061"];
+    useGoogleAPIs = false;
+    useGoogleTVAddOns = false;
+    includeExtras = [
+      "extras;google;gcm"
+    ];
+  };
+in
+androidComposition.androidsdk
+```
+
+The above function invocation states that we want an Android SDK with the above
+specified plugin versions. By default, most plugins are disabled. Notable
+exceptions are the tools, platform-tools and build-tools sub packages.
+
+The following parameters are supported:
+
+* `toolsVersion`, specifies the version of the tools package to use
+* `platformsToolsVersion` specifies the version of the `platform-tools` plugin
+* `buildToolsVersions` specifies the versions of the `build-tools` plugins to
+  use.
+* `includeEmulator` specifies whether to deploy the emulator package (`false`
+  by default). When enabled, the version of the emulator to deploy can be
+  specified by setting the `emulatorVersion` parameter.
+* `cmakeVersions` specifies which CMake versions should be deployed.
+* `includeNDK` specifies that the Android NDK bundle should be included.
+  Defaults to: `false`.
+* `ndkVersions` specifies the NDK versions that we want to use. These are linked
+  under the `ndk` directory of the SDK root, and the first is linked under the
+  `ndk-bundle` directory.
+* `ndkVersion` is equivalent to specifying one entry in `ndkVersions`, and
+  `ndkVersions` overrides this parameter if provided.
+* `includeExtras` is an array of identifier strings referring to arbitrary
+  add-on packages that should be installed.
+* `platformVersions` specifies which platform SDK versions should be included.
+
+For each platform version that has been specified, we can apply the following
+options:
+
+* `includeSystemImages` specifies whether a system image for each platform SDK
+  should be included.
+* `includeSources` specifies whether the sources for each SDK version should be
+  included.
+* `useGoogleAPIs` specifies that for each selected platform version the
+  Google API should be included.
+* `useGoogleTVAddOns` specifies that for each selected platform version the
+  Google TV add-on should be included.
+
+For each requested system image we can specify the following options:
+
+* `systemImageTypes` specifies what kind of system images should be included.
+  Defaults to: `default`.
+* `abiVersions` specifies what kind of ABI version of each system image should
+  be included. Defaults to: `armeabi-v7a`.
+
+Most of the function arguments have reasonable default settings.
+
+You can specify license names:
+
+* `extraLicenses` is a list of license names.
+  You can get these names from repo.json or `querypackages.sh licenses`. The SDK
+  license (`android-sdk-license`) is accepted for you if you set accept_license
+  to true. If you are doing something like working with preview SDKs, you will
+  want to add `android-sdk-preview-license` or whichever license applies here.
+
+Additionally, you can override the repositories that composeAndroidPackages will
+pull from:
+
+* `repoJson` specifies a path to a generated repo.json file. You can generate this
+  by running `generate.sh`, which in turn will call into `mkrepo.rb`.
+* `repoXmls` is an attribute set containing paths to repo XML files. If specified,
+  it takes priority over `repoJson`, and will trigger a local build writing out a
+  repo.json to the Nix store based on the given repository XMLs.
+
+```nix
+repoXmls = {
+  packages = [ ./xml/repository2-1.xml ];
+  images = [
+    ./xml/android-sys-img2-1.xml
+    ./xml/android-tv-sys-img2-1.xml
+    ./xml/android-wear-sys-img2-1.xml
+    ./xml/android-wear-cn-sys-img2-1.xml
+    ./xml/google_apis-sys-img2-1.xml
+    ./xml/google_apis_playstore-sys-img2-1.xml
+  ];
+  addons = [ ./xml/addon2-1.xml ];
+};
+```
+
+When building the above expression with:
+
+```bash
+$ nix-build
+```
+
+The Android SDK gets deployed with all desired plugin versions.
+
+We can also deploy subsets of the Android SDK. For example, to only the
+`platform-tools` package, you can evaluate the following expression:
+
+```nix
+with import <nixpkgs> {};
+
+let
+  androidComposition = androidenv.composeAndroidPackages {
+    # ...
+  };
+in
+androidComposition.platform-tools
+```
+
+## Using predefined Android package compositions {#using-predefined-android-package-compositions}
+
+In addition to composing an Android package set manually, it is also possible
+to use a predefined composition that contains all basic packages for a specific
+Android version, such as version 9.0 (API-level 28).
+
+The following Nix expression can be used to deploy the entire SDK with all basic
+plugins:
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.androidPkgs_9_0.androidsdk
+```
+
+It is also possible to use one plugin only:
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.androidPkgs_9_0.platform-tools
+```
+
+## Building an Android application {#building-an-android-application}
+
+In addition to the SDK, it is also possible to build an Ant-based Android
+project and automatically deploy all the Android plugins that a project
+requires.
+
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.buildApp {
+  name = "MyAndroidApp";
+  src = ./myappsources;
+  release = true;
+
+  # If release is set to true, you need to specify the following parameters
+  keyStore = ./keystore;
+  keyAlias = "myfirstapp";
+  keyStorePassword = "mykeystore";
+  keyAliasPassword = "myfirstapp";
+
+  # Any Android SDK parameters that install all the relevant plugins that a
+  # build requires
+  platformVersions = [ "24" ];
+
+  # When we include the NDK, then ndk-build is invoked before Ant gets invoked
+  includeNDK = true;
+}
+```
+
+Aside from the app-specific build parameters (`name`, `src`, `release` and
+keystore parameters), the `buildApp {}` function supports all the function
+parameters that the SDK composition function (the function shown in the
+previous section) supports.
+
+This build function is particularly useful when it is desired to use
+[Hydra](https://nixos.org/hydra): the Nix-based continuous integration solution
+to build Android apps. An Android APK gets exposed as a build product and can be
+installed on any Android device with a web browser by navigating to the build
+result page.
+
+## Spawning emulator instances {#spawning-emulator-instances}
+
+For testing purposes, it can also be quite convenient to automatically generate
+scripts that spawn emulator instances with all desired configuration settings.
+
+An emulator spawn script can be configured by invoking the `emulateApp {}`
+function:
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.emulateApp {
+  name = "emulate-MyAndroidApp";
+  platformVersion = "28";
+  abiVersion = "x86"; # armeabi-v7a, mips, x86_64
+  systemImageType = "google_apis_playstore";
+}
+```
+
+Additional flags may be applied to the Android SDK's emulator through the runtime environment variable `$NIX_ANDROID_EMULATOR_FLAGS`.
+
+It is also possible to specify an APK to deploy inside the emulator
+and the package and activity names to launch it:
+
+```nix
+with import <nixpkgs> {};
+
+androidenv.emulateApp {
+  name = "emulate-MyAndroidApp";
+  platformVersion = "24";
+  abiVersion = "armeabi-v7a"; # mips, x86, x86_64
+  systemImageType = "default";
+  useGoogleAPIs = false;
+  app = ./MyApp.apk;
+  package = "MyApp";
+  activity = "MainActivity";
+}
+```
+
+In addition to prebuilt APKs, you can also bind the APK parameter to a
+`buildApp {}` function invocation shown in the previous example.
+
+## Notes on environment variables in Android projects {#notes-on-environment-variables-in-android-projects}
+
+* `ANDROID_SDK_ROOT` should point to the Android SDK. In your Nix expressions, this should be
+  `${androidComposition.androidsdk}/libexec/android-sdk`. Note that `ANDROID_HOME` is deprecated,
+  but if you rely on tools that need it, you can export it too.
+* `ANDROID_NDK_ROOT` should point to the Android NDK, if you're doing NDK development.
+  In your Nix expressions, this should be `${ANDROID_SDK_ROOT}/ndk-bundle`.
+
+If you are running the Android Gradle plugin, you need to export GRADLE_OPTS to override aapt2
+to point to the aapt2 binary in the Nix store as well, or use a FHS environment so the packaged
+aapt2 can run. If you don't want to use a FHS environment, something like this should work:
+
+```nix
+let
+  buildToolsVersion = "30.0.3";
+
+  # Use buildToolsVersion when you define androidComposition
+  androidComposition = <...>;
+in
+pkgs.mkShell rec {
+  ANDROID_SDK_ROOT = "${androidComposition.androidsdk}/libexec/android-sdk";
+  ANDROID_NDK_ROOT = "${ANDROID_SDK_ROOT}/ndk-bundle";
+
+  # Use the same buildToolsVersion here
+  GRADLE_OPTS = "-Dorg.gradle.project.android.aapt2FromMavenOverride=${ANDROID_SDK_ROOT}/build-tools/${buildToolsVersion}/aapt2";
+}
+```
+
+If you are using cmake, you need to add it to PATH in a shell hook or FHS env profile.
+The path is suffixed with a build number, but properly prefixed with the version.
+So, something like this should suffice:
+
+```nix
+let
+  cmakeVersion = "3.10.2";
+
+  # Use cmakeVersion when you define androidComposition
+  androidComposition = <...>;
+in
+pkgs.mkShell rec {
+  ANDROID_SDK_ROOT = "${androidComposition.androidsdk}/libexec/android-sdk";
+  ANDROID_NDK_ROOT = "${ANDROID_SDK_ROOT}/ndk-bundle";
+
+  # Use the same cmakeVersion here
+  shellHook = ''
+    export PATH="$(echo "$ANDROID_SDK_ROOT/cmake/${cmakeVersion}".*/bin):$PATH"
+  '';
+}
+```
+
+Note that running Android Studio with ANDROID_SDK_ROOT set will automatically write a
+`local.properties` file with `sdk.dir` set to $ANDROID_SDK_ROOT if one does not already
+exist. If you are using the NDK as well, you may have to add `ndk.dir` to this file.
+
+An example shell.nix that does all this for you is provided in examples/shell.nix.
+This shell.nix includes a shell hook that overwrites local.properties with the correct
+sdk.dir and ndk.dir values. This will ensure that the SDK and NDK directories will
+both be correct when you run Android Studio inside nix-shell.
+
+## Notes on improving build.gradle compatibility {#notes-on-improving-build.gradle-compatibility}
+
+Ensure that your buildToolsVersion and ndkVersion match what is declared in androidenv.
+If you are using cmake, make sure its declared version is correct too.
+
+Otherwise, you may get cryptic errors from aapt2 and the Android Gradle plugin warning
+that it cannot install the build tools because the SDK directory is not writeable.
+
+```gradle
+android {
+    buildToolsVersion "30.0.3"
+    ndkVersion = "22.0.7026061"
+    externalNativeBuild {
+        cmake {
+            version "3.10.2"
+        }
+    }
+}
+
+```
+
+## Querying the available versions of each plugin {#querying-the-available-versions-of-each-plugin}
+
+repo.json provides all the options in one file now.
+
+A shell script in the `pkgs/development/mobile/androidenv/` subdirectory can be used to retrieve all
+possible options:
+
+```bash
+./querypackages.sh packages
+```
+
+The above command-line instruction queries all package versions in repo.json.
+
+## Updating the generated expressions {#updating-the-generated-expressions}
+
+repo.json is generated from XML files that the Android Studio package manager uses.
+To update the expressions run the `generate.sh` script that is stored in the
+`pkgs/development/mobile/androidenv/` subdirectory:
+
+```bash
+./generate.sh
+```

doc/languages-frameworks/beam.section.md

@@ -0,0 +1,373 @@
+# BEAM Languages (Erlang, Elixir & LFE) {#sec-beam}
+
+## Introduction {#beam-introduction}
+
+In this document and related Nix expressions, we use the term, _BEAM_, to describe the environment. BEAM is the name of the Erlang Virtual Machine and, as far as we're concerned, from a packaging perspective, all languages that run on the BEAM are interchangeable. That which varies, like the build system, is transparent to users of any given BEAM package, so we make no distinction.
+
+## Available versions and deprecations schedule {#available-versions-and-deprecations-schedule}
+
+### Elixir {#elixir}
+
+nixpkgs follows the [official elixir deprecation schedule](https://hexdocs.pm/elixir/compatibility-and-deprecations.html) and keeps the last 5 released versions of Elixir available.
+
+## Structure {#beam-structure}
+
+All BEAM-related expressions are available via the top-level `beam` attribute, which includes:
+
+- `interpreters`: a set of compilers running on the BEAM, including multiple Erlang/OTP versions (`beam.interpreters.erlangR22`, etc), Elixir (`beam.interpreters.elixir`) and LFE (Lisp Flavoured Erlang) (`beam.interpreters.lfe`).
+
+- `packages`: a set of package builders (Mix and rebar3), each compiled with a specific Erlang/OTP version, e.g. `beam.packages.erlang22`.
+
+The default Erlang compiler, defined by `beam.interpreters.erlang`, is aliased as `erlang`. The default BEAM package set is defined by `beam.packages.erlang` and aliased at the top level as `beamPackages`.
+
+To create a package builder built with a custom Erlang version, use the lambda, `beam.packagesWith`, which accepts an Erlang/OTP derivation and produces a package builder similar to `beam.packages.erlang`.
+
+Many Erlang/OTP distributions available in `beam.interpreters` have versions with ODBC and/or Java enabled or without wx (no observer support). For example, there's `beam.interpreters.erlangR22_odbc_javac`, which corresponds to `beam.interpreters.erlangR22` and `beam.interpreters.erlangR22_nox`, which corresponds to `beam.interpreters.erlangR22`.
+
+## Build Tools {#build-tools}
+
+### Rebar3 {#build-tools-rebar3}
+
+We provide a version of Rebar3, under `rebar3`. We also provide a helper to fetch Rebar3 dependencies from a lockfile under `fetchRebar3Deps`.
+
+We also provide a version on Rebar3 with plugins included, under `rebar3WithPlugins`. This package is a function which takes two arguments: `plugins`, a list of nix derivations to include as plugins (loaded only when specified in `rebar.config`), and `globalPlugins`, which should always be loaded by rebar3. Example: `rebar3WithPlugins { globalPlugins = [beamPackages.pc]; }`.
+
+When adding a new plugin it is important that the `packageName` attribute is the same as the atom used by rebar3 to refer to the plugin.
+
+### Mix & Erlang.mk {#build-tools-other}
+
+Erlang.mk works exactly as expected. There is a bootstrap process that needs to be run, which is supported by the `buildErlangMk` derivation.
+
+For Elixir applications use `mixRelease` to make a release. See examples for more details.
+
+There is also a `buildMix` helper, whose behavior is closer to that of `buildErlangMk` and `buildRebar3`. The primary difference is that mixRelease makes a release, while buildMix only builds the package, making it useful for libraries and other dependencies.
+
+## How to Install BEAM Packages {#how-to-install-beam-packages}
+
+BEAM builders are not registered at the top level, simply because they are not relevant to the vast majority of Nix users. To install any of those builders into your profile, refer to them by their attribute path `beamPackages.rebar3`:
+
+```ShellSession
+$ nix-env -f "<nixpkgs>" -iA beamPackages.rebar3
+```
+
+## Packaging BEAM Applications {#packaging-beam-applications}
+
+### Erlang Applications {#packaging-erlang-applications}
+
+#### Rebar3 Packages {#rebar3-packages}
+
+The Nix function, `buildRebar3`, defined in `beam.packages.erlang.buildRebar3` and aliased at the top level, can be used to build a derivation that understands how to build a Rebar3 project.
+
+If a package needs to compile native code via Rebar3's port compilation mechanism, add `compilePort = true;` to the derivation.
+
+#### Erlang.mk Packages {#erlang-mk-packages}
+
+Erlang.mk functions similarly to Rebar3, except we use `buildErlangMk` instead of `buildRebar3`.
+
+#### Mix Packages {#mix-packages}
+
+`mixRelease` is used to make a release in the mix sense. Dependencies will need to be fetched with `fetchMixDeps` and passed to it.
+
+#### mixRelease - Elixir Phoenix example {#mix-release-elixir-phoenix-example}
+
+there are 3 steps, frontend dependencies (javascript), backend dependencies (elixir) and the final derivation that puts both of those together
+
+##### mixRelease - Frontend dependencies (javascript) {#mix-release-javascript-deps}
+
+For phoenix projects, inside of nixpkgs you can either use yarn2nix (mkYarnModule) or node2nix. An example with yarn2nix can be found [here](https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/web-apps/plausible/default.nix#L39). An example with node2nix will follow. To package something outside of nixpkgs, you have alternatives like [npmlock2nix](https://github.com/nix-community/npmlock2nix) or [nix-npm-buildpackage](https://github.com/serokell/nix-npm-buildpackage)
+
+##### mixRelease - backend dependencies (mix) {#mix-release-mix-deps}
+
+There are 2 ways to package backend dependencies. With mix2nix and with a fixed-output-derivation (FOD).
+
+###### mix2nix {#mix2nix}
+
+`mix2nix` is a cli tool available in nixpkgs. it will generate a nix expression from a mix.lock file. It is quite standard in the 2nix tool series.
+
+Note that currently mix2nix can't handle git dependencies inside the mix.lock file. If you have git dependencies, you can either add them manually (see [example](https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/pleroma/default.nix#L20)) or use the FOD method.
+
+The advantage of using mix2nix is that nix will know your whole dependency graph. On a dependency update, this won't trigger a full rebuild and download of all the dependencies, where FOD will do so.
+
+Practical steps:
+
+- run `mix2nix > mix_deps.nix` in the upstream repo.
+- pass `mixNixDeps = with pkgs; import ./mix_deps.nix { inherit lib beamPackages; };` as an argument to mixRelease.
+
+If there are git depencencies.
+
+- You'll need to fix the version artificially in mix.exs and regenerate the mix.lock with fixed version (on upstream). This will enable you to run `mix2nix > mix_deps.nix`.
+- From the mix_deps.nix file, remove the dependencies that had git versions and pass them as an override to the import function.
+
+```nix
+  mixNixDeps = import ./mix.nix {
+    inherit beamPackages lib;
+    overrides = (final: prev: {
+      # mix2nix does not support git dependencies yet,
+      # so we need to add them manually
+      prometheus_ex = beamPackages.buildMix rec {
+        name = "prometheus_ex";
+        version = "3.0.5";
+
+        # Change the argument src with the git src that you actually need
+        src = fetchFromGitLab {
+          domain = "git.pleroma.social";
+          group = "pleroma";
+          owner = "elixir-libraries";
+          repo = "prometheus.ex";
+          rev = "a4e9beb3c1c479d14b352fd9d6dd7b1f6d7deee5";
+          sha256 = "1v0q4bi7sb253i8q016l7gwlv5562wk5zy3l2sa446csvsacnpjk";
+        };
+        # you can re-use the same beamDeps argument as generated
+        beamDeps = with final; [ prometheus ];
+      };
+  });
+};
+```
+
+You will need to run the build process once to fix the sha256 to correspond to your new git src.
+
+###### FOD {#fixed-output-derivation}
+
+A fixed output derivation will download mix dependencies from the internet. To ensure reproducibility, a hash will be supplied. Note that mix is relatively reproducible. An FOD generating a different hash on each run hasn't been observed (as opposed to npm where the chances are relatively high). See [elixir_ls](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/beam-modules/elixir_ls.nix) for a usage example of FOD.
+
+Practical steps
+
+- start with the following argument to mixRelease
+
+```nix
+  mixFodDeps = fetchMixDeps {
+    pname = "mix-deps-${pname}";
+    inherit src version;
+    sha256 = lib.fakeSha256;
+  };
+```
+
+The first build will complain about the sha256 value, you can replace with the suggested value after that.
+
+Note that if after you've replaced the value, nix suggests another sha256, then mix is not fetching the dependencies reproducibly. An FOD will not work in that case and you will have to use mix2nix.
+
+##### mixRelease - example {#mix-release-example}
+
+Here is how your `default.nix` file would look for a phoenix project.
+
+```nix
+with import <nixpkgs> { };
+
+let
+  # beam.interpreters.erlangR23 is available if you need a particular version
+  packages = beam.packagesWith beam.interpreters.erlang;
+
+  pname = "your_project";
+  version = "0.0.1";
+
+  src = builtins.fetchgit {
+    url = "ssh://git@github.com/your_id/your_repo";
+    rev = "replace_with_your_commit";
+  };
+
+  # if using mix2nix you can use the mixNixDeps attribute
+  mixFodDeps = packages.fetchMixDeps {
+    pname = "mix-deps-${pname}";
+    inherit src version;
+    # nix will complain and tell you the right value to replace this with
+    sha256 = lib.fakeSha256;
+    # if you have build time environment variables add them here
+    MY_ENV_VAR="my_value";
+  };
+
+  nodeDependencies = (pkgs.callPackage ./assets/default.nix { }).shell.nodeDependencies;
+
+in packages.mixRelease {
+  inherit src pname version mixFodDeps;
+  # if you have build time environment variables add them here
+  MY_ENV_VAR="my_value";
+
+  postBuild = ''
+    ln -sf ${nodeDependencies}/lib/node_modules assets/node_modules
+    npm run deploy --prefix ./assets
+
+    # for external task you need a workaround for the no deps check flag
+    # https://github.com/phoenixframework/phoenix/issues/2690
+    mix do deps.loadpaths --no-deps-check, phx.digest
+    mix phx.digest --no-deps-check
+  '';
+}
+```
+
+Setup will require the following steps:
+
+- Move your secrets to runtime environment variables. For more information refer to the [runtime.exs docs](https://hexdocs.pm/mix/Mix.Tasks.Release.html#module-runtime-configuration). On a fresh Phoenix build that would mean that both `DATABASE_URL` and `SECRET_KEY` need to be moved to `runtime.exs`.
+- `cd assets` and `nix-shell -p node2nix --run node2nix --development` will generate a Nix expression containing your frontend dependencies
+- commit and push those changes
+- you can now `nix-build .`
+- To run the release, set the `RELEASE_TMP` environment variable to a directory that your program has write access to. It will be used to store the BEAM settings.
+
+#### Example of creating a service for an Elixir - Phoenix project {#example-of-creating-a-service-for-an-elixir---phoenix-project}
+
+In order to create a service with your release, you could add a `service.nix`
+in your project with the following
+
+```nix
+{config, pkgs, lib, ...}:
+
+let
+  release = pkgs.callPackage ./default.nix;
+  release_name = "app";
+  working_directory = "/home/app";
+in
+{
+  systemd.services.${release_name} = {
+    wantedBy = [ "multi-user.target" ];
+    after = [ "network.target" "postgresql.service" ];
+    # note that if you are connecting to a postgres instance on a different host
+    # postgresql.service should not be included in the requires.
+    requires = [ "network-online.target" "postgresql.service" ];
+    description = "my app";
+    environment = {
+      # RELEASE_TMP is used to write the state of the
+      # VM configuration when the system is running
+      # it needs to be a writable directory
+      RELEASE_TMP = working_directory;
+      # can be generated in an elixir console with
+      # Base.encode32(:crypto.strong_rand_bytes(32))
+      RELEASE_COOKIE = "my_cookie";
+      MY_VAR = "my_var";
+    };
+    serviceConfig = {
+      Type = "exec";
+      DynamicUser = true;
+      WorkingDirectory = working_directory;
+      # Implied by DynamicUser, but just to emphasize due to RELEASE_TMP
+      PrivateTmp = true;
+      ExecStart = ''
+        ${release}/bin/${release_name} start
+      '';
+      ExecStop = ''
+        ${release}/bin/${release_name} stop
+      '';
+      ExecReload = ''
+        ${release}/bin/${release_name} restart
+      '';
+      Restart = "on-failure";
+      RestartSec = 5;
+      StartLimitBurst = 3;
+      StartLimitInterval = 10;
+    };
+    # disksup requires bash
+    path = [ pkgs.bash ];
+  };
+
+  # in case you have migration scripts or you want to use a remote shell
+  environment.systemPackages = [ release ];
+}
+```
+
+## How to Develop {#how-to-develop}
+
+### Creating a Shell {#creating-a-shell}
+
+Usually, we need to create a `shell.nix` file and do our development inside of the environment specified therein. Just install your version of Erlang and any other interpreters, and then use your normal build tools. As an example with Elixir:
+
+```nix
+{ pkgs ? import <nixpkgs> {} }:
+
+with pkgs;
+let
+  elixir = beam.packages.erlangR24.elixir_1_12;
+in
+mkShell {
+  buildInputs = [ elixir ];
+}
+```
+
+### Using an overlay
+
+If you need to use an overlay to change some attributes of a derivation, e.g. if you need a bugfix from a version that is not yet available in nixpkgs, you can override attributes such as `version` (and the corresponding `sha256`) and then use this overlay in your development environment:
+
+#### `shell.nix`
+
+```nix
+let
+  elixir_1_13_1_overlay = (self: super: {
+      elixir_1_13 = super.elixir_1_13.override {
+        version = "1.13.1";
+        sha256 = "0z0b1w2vvw4vsnb99779c2jgn9bgslg7b1pmd9vlbv02nza9qj5p";
+      };
+    });
+  pkgs = import <nixpkgs> { overlays = [ elixir_1_13_1_overlay ]; };
+in
+with pkgs;
+mkShell {
+  buildInputs = [
+    elixir_1_13
+  ];
+}
+```
+
+#### Elixir - Phoenix project {#elixir---phoenix-project}
+
+Here is an example `shell.nix`.
+
+```nix
+with import <nixpkgs> { };
+
+let
+  # define packages to install
+  basePackages = [
+    git
+    # replace with beam.packages.erlang.elixir_1_13 if you need
+    beam.packages.erlang.elixir
+    nodejs
+    postgresql_14
+    # only used for frontend dependencies
+    # you are free to use yarn2nix as well
+    nodePackages.node2nix
+    # formatting js file
+    nodePackages.prettier
+  ];
+
+  inputs = basePackages ++ lib.optionals stdenv.isLinux [ inotify-tools ]
+    ++ lib.optionals stdenv.isDarwin
+    (with darwin.apple_sdk.frameworks; [ CoreFoundation CoreServices ]);
+
+  # define shell startup command
+  hooks = ''
+    # this allows mix to work on the local directory
+    mkdir -p .nix-mix .nix-hex
+    export MIX_HOME=$PWD/.nix-mix
+    export HEX_HOME=$PWD/.nix-mix
+    # make hex from Nixpkgs available
+    # `mix local.hex` will install hex into MIX_HOME and should take precedence
+    export MIX_PATH="${beam.packages.erlang.hex}/lib/erlang/lib/hex/ebin"
+    export PATH=$MIX_HOME/bin:$HEX_HOME/bin:$PATH
+    export LANG=C.UTF-8
+    # keep your shell history in iex
+    export ERL_AFLAGS="-kernel shell_history enabled"
+
+    # postges related
+    # keep all your db data in a folder inside the project
+    export PGDATA="$PWD/db"
+
+    # phoenix related env vars
+    export POOL_SIZE=15
+    export DB_URL="postgresql://postgres:postgres@localhost:5432/db"
+    export PORT=4000
+    export MIX_ENV=dev
+    # add your project env vars here, word readable in the nix store.
+    export ENV_VAR="your_env_var"
+  '';
+
+in mkShell {
+  buildInputs = inputs;
+  shellHook = hooks;
+}
+```
+
+Initializing the project will require the following steps:
+
+- create the db directory `initdb ./db` (inside your mix project folder)
+- create the postgres user `createuser postgres -ds`
+- create the db `createdb db`
+- start the postgres instance `pg_ctl -l "$PGDATA/server.log" start`
+- add the `/db` folder to your `.gitignore`
+- you can start your phoenix server and get a shell with `iex -S mix phx.server`

doc/languages-frameworks/bower.section.md

@@ -0,0 +1,158 @@
+# Bower {#sec-bower}
+
+[Bower](https://bower.io) is a package manager for web site front-end components. Bower packages (comprising of build artefacts and sometimes sources) are stored in `git` repositories, typically on Github. The package registry is run by the Bower team with package metadata coming from the `bower.json` file within each package.
+
+The end result of running Bower is a `bower_components` directory which can be included in the web app's build process.
+
+Bower can be run interactively, by installing `nodePackages.bower`. More interestingly, the Bower components can be declared in a Nix derivation, with the help of `nodePackages.bower2nix`.
+
+## bower2nix usage {#ssec-bower2nix-usage}
+
+Suppose you have a `bower.json` with the following contents:
+
+### Example bower.json {#ex-bowerJson}
+
+```json
+  "name": "my-web-app",
+  "dependencies": {
+    "angular": "~1.5.0",
+    "bootstrap": "~3.3.6"
+  }
+```
+
+Running `bower2nix` will produce something like the following output:
+
+```nix
+{ fetchbower, buildEnv }:
+buildEnv { name = "bower-env"; ignoreCollisions = true; paths = [
+  (fetchbower "angular" "1.5.3" "~1.5.0" "1749xb0firxdra4rzadm4q9x90v6pzkbd7xmcyjk6qfza09ykk9y")
+  (fetchbower "bootstrap" "3.3.6" "~3.3.6" "1vvqlpbfcy0k5pncfjaiskj3y6scwifxygfqnw393sjfxiviwmbv")
+  (fetchbower "jquery" "2.2.2" "1.9.1 - 2" "10sp5h98sqwk90y4k6hbdviwqzvzwqf47r3r51pakch5ii2y7js1")
+];
+```
+
+Using the `bower2nix` command line arguments, the output can be redirected to a file. A name like `bower-packages.nix` would be fine.
+
+The resulting derivation is a union of all the downloaded Bower packages (and their dependencies). To use it, they still need to be linked together by Bower, which is where `buildBowerComponents` is useful.
+
+## buildBowerComponents function {#ssec-build-bower-components}
+
+The function is implemented in [pkgs/development/bower-modules/generic/default.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/bower-modules/generic/default.nix).
+
+### Example buildBowerComponents {#ex-buildBowerComponents}
+
+```{=docbook}
+<programlisting language="nix">
+bowerComponents = buildBowerComponents {
+  name = "my-web-app";
+  generated = ./bower-packages.nix; <co xml:id="ex-buildBowerComponents-1" />
+  src = myWebApp; <co xml:id="ex-buildBowerComponents-2" />
+};
+</programlisting>
+```
+
+In ["buildBowerComponents" example](#ex-buildBowerComponents) the following arguments are of special significance to the function:
+
+```{=docbook}
+<calloutlist>
+  <callout arearefs="ex-buildBowerComponents-1">
+    <para>
+      <varname>generated</varname> specifies the file which was created by <command>bower2nix</command>.
+    </para>
+    </callout>
+      <callout arearefs="ex-buildBowerComponents-2">
+    <para>
+      <varname>src</varname> is your project's sources. It needs to contain a <filename>bower.json</filename> file.
+    </para>
+  </callout>
+</calloutlist>
+```
+
+`buildBowerComponents` will run Bower to link together the output of `bower2nix`, resulting in a `bower_components` directory which can be used.
+
+Here is an example of a web frontend build process using `gulp`. You might use `grunt`, or anything else.
+
+### Example build script (gulpfile.js) {#ex-bowerGulpFile}
+
+```javascript
+var gulp = require('gulp');
+
+gulp.task('default', [], function () {
+  gulp.start('build');
+});
+
+gulp.task('build', [], function () {
+  console.log("Just a dummy gulp build");
+  gulp
+    .src(["./bower_components/**/*"])
+    .pipe(gulp.dest("./gulpdist/"));
+});
+```
+
+### Example Full example — default.nix {#ex-buildBowerComponentsDefaultNix}
+
+```{=docbook}
+<programlisting language="nix">
+{ myWebApp ? { outPath = ./.; name = "myWebApp"; }
+, pkgs ? import &lt;nixpkgs&gt; {}
+}:
+
+pkgs.stdenv.mkDerivation {
+  name = "my-web-app-frontend";
+  src = myWebApp;
+
+  buildInputs = [ pkgs.nodePackages.gulp ];
+
+  bowerComponents = pkgs.buildBowerComponents { <co xml:id="ex-buildBowerComponentsDefault-1" />
+    name = "my-web-app";
+    generated = ./bower-packages.nix;
+    src = myWebApp;
+  };
+
+  buildPhase = ''
+    cp --reflink=auto --no-preserve=mode -R $bowerComponents/bower_components . <co xml:id="ex-buildBowerComponentsDefault-2" />
+    export HOME=$PWD <co xml:id="ex-buildBowerComponentsDefault-3" />
+    ${pkgs.nodePackages.gulp}/bin/gulp build <co xml:id="ex-buildBowerComponentsDefault-4" />
+  '';
+
+  installPhase = "mv gulpdist $out";
+}
+</programlisting>
+```
+
+A few notes about [Full example — `default.nix`](#ex-buildBowerComponentsDefaultNix):
+
+```{=docbook}
+<calloutlist>
+  <callout arearefs="ex-buildBowerComponentsDefault-1">
+    <para>
+      The result of <varname>buildBowerComponents</varname> is an input to the frontend build.
+    </para>
+  </callout>
+  <callout arearefs="ex-buildBowerComponentsDefault-2">
+    <para>
+      Whether to symlink or copy the <filename>bower_components</filename> directory depends on the build tool in use. In this case a copy is used to avoid <command>gulp</command> silliness with permissions.
+    </para>
+  </callout>
+  <callout arearefs="ex-buildBowerComponentsDefault-3">
+    <para>
+      <command>gulp</command> requires <varname>HOME</varname> to refer to a writeable directory.
+    </para>
+  </callout>
+  <callout arearefs="ex-buildBowerComponentsDefault-4">
+    <para>
+      The actual build command. Other tools could be used.
+    </para>
+  </callout>
+</calloutlist>
+```
+
+## Troubleshooting {#ssec-bower2nix-troubleshooting}
+
+### ENOCACHE errors from buildBowerComponents {#enocache-errors-from-buildbowercomponents}
+
+This means that Bower was looking for a package version which doesn't exist in the generated `bower-packages.nix`.
+
+If `bower.json` has been updated, then run `bower2nix` again.
+
+It could also be a bug in `bower2nix` or `fetchbower`. If possible, try reformulating the version specification in `bower.json`.

doc/languages-frameworks/chicken.section.md

@@ -0,0 +1,49 @@
+# CHICKEN {#sec-chicken}
+
+[CHICKEN](https://call-cc.org/) is a
+[R⁵RS](https://schemers.org/Documents/Standards/R5RS/HTML/)-compliant Scheme
+compiler. It includes an interactive mode and a custom package format, "eggs".
+
+## Using Eggs
+
+Eggs described in nixpkgs are available inside the
+`chickenPackages.chickenEggs` attrset. Including an egg as a build input is
+done in the typical Nix fashion. For example, to include support for [SRFI
+189](https://srfi.schemers.org/srfi-189/srfi-189.html) in a derivation, one
+might write:
+
+```nix
+  buildInputs = [
+    chicken
+    chickenPackages.chickenEggs.srfi-189
+  ];
+```
+
+Both `chicken` and its eggs have a setup hook which configures the environment
+variables `CHICKEN_INCLUDE_PATH` and `CHICKEN_REPOSITORY_PATH`.
+
+## Updating Eggs
+
+nixpkgs only knows about a subset of all published eggs. It uses
+[egg2nix](https://github.com/the-kenny/egg2nix) to generate a
+package set from a list of eggs to include.
+
+The package set is regenerated by running the following shell commands:
+
+```
+$ nix-shell -p chickenPackages.egg2nix
+$ cd pkgs/development/compilers/chicken/5/
+$ egg2nix eggs.scm > eggs.nix
+```
+
+## Adding Eggs
+
+When we run `egg2nix`, we obtain one collection of eggs with
+mutually-compatible versions. This means that when we add new eggs, we may
+need to update existing eggs. To keep those separate, follow the procedure for
+updating eggs before including more eggs.
+
+To include more eggs, edit `pkgs/development/compilers/chicken/5/eggs.scm`.
+The first section of this file lists eggs which are required by `egg2nix`
+itself; all other eggs go into the second section. After editing, follow the
+procedure for updating eggs.

doc/languages-frameworks/coq.section.md

@@ -0,0 +1,88 @@
+# Coq and coq packages {#sec-language-coq}
+
+## Coq derivation: `coq` {#coq-derivation-coq}
+
+The Coq derivation is overridable through the `coq.override overrides`, where overrides is an attribute set which contains the arguments to override. We recommend overriding either of the following
+
+* `version` (optional, defaults to the latest version of Coq selected for nixpkgs, see `pkgs/top-level/coq-packages` to witness this choice), which follows the conventions explained in the `coqPackages` section below,
+* `customOCamlPackage` (optional, defaults to `null`, which lets Coq choose a version automatically), which can be set to any of the ocaml packages attribute of `ocaml-ng` (such as `ocaml-ng.ocamlPackages_4_10` which is the default for Coq 8.11 for example).
+* `coq-version` (optional, defaults to the short version e.g. "8.10"), is a version number of the form "x.y" that indicates which Coq's version build behavior to mimic when using a source which is not a release. E.g. `coq.override { version = "d370a9d1328a4e1cdb9d02ee032f605a9d94ec7a"; coq-version = "8.10"; }`.
+
+## Coq packages attribute sets: `coqPackages` {#coq-packages-attribute-sets-coqpackages}
+
+The recommended way of defining a derivation for a Coq library, is to use the `coqPackages.mkCoqDerivation` function, which is essentially a specialization of `mkDerivation` taking into account most of the specifics of Coq libraries. The following attributes are supported:
+
+* `pname` (required) is the name of the package,
+* `version` (optional, defaults to `null`), is the version to fetch and build,
+  this attribute is interpreted in several ways depending on its type and pattern:
+  * if it is a known released version string, i.e. from the `release` attribute below, the according release is picked, and the `version` attribute of the resulting derivation is set to this release string,
+  * if it is a majorMinor `"x.y"` prefix of a known released version (as defined above), then the latest `"x.y.z"` known released version is selected (for the ordering given by `versionAtLeast`),
+  * if it is a path or a string representing an absolute path (i.e. starting with `"/"`), the provided path is selected as a source, and the `version` attribute of the resulting derivation is set to `"dev"`,
+  * if it is a string of the form `owner:branch` then it tries to download the `branch` of owner `owner` for a project of the same name using the same vcs, and the `version` attribute of the resulting derivation is set to `"dev"`, additionally if the owner is not provided (i.e. if the `owner:` prefix is missing), it defaults to the original owner of the package (see below),
+  * if it is a string of the form `"#N"`, and the domain is github, then it tries to download the current head of the pull request `#N` from github,
+* `defaultVersion` (optional). Coq libraries may be compatible with some specific versions of Coq only. The `defaultVersion` attribute is used when no `version` is provided (or if `version = null`) to select the version of the library to use by default, depending on the context. This selection will mainly depend on a `coq` version number but also possibly on other packages versions (e.g. `mathcomp`). If its value ends up to be `null`, the package is marked for removal in end-user `coqPackages` attribute set.
+* `release` (optional, defaults to `{}`), lists all the known releases of the library and for each of them provides an attribute set with at least a `sha256` attribute (you may put the empty string `""` in order to automatically insert a fake sha256, this will trigger an error which will allow you to find the correct sha256), each attribute set of the list of releases also takes optional overloading arguments for the fetcher as below (i.e.`domain`, `owner`, `repo`, `rev` assuming the default fetcher is used) and optional overrides for the result of the fetcher (i.e. `version` and `src`).
+* `fetcher` (optional, defaults to a generic fetching mechanism supporting github or gitlab based infrastructures), is a function that takes at least an `owner`, a `repo`, a `rev`, and a `sha256` and returns an attribute set with a `version` and `src`.
+* `repo` (optional, defaults to the value of `pname`),
+* `owner` (optional, defaults to `"coq-community"`).
+* `domain` (optional, defaults to `"github.com"`), domains including the strings `"github"` or `"gitlab"` in their names are automatically supported, otherwise, one must change the `fetcher` argument to support them (cf `pkgs/development/coq-modules/heq/default.nix` for an example),
+* `releaseRev` (optional, defaults to `(v: v)`), provides a default mapping from release names to revision hashes/branch names/tags,
+* `displayVersion` (optional), provides a way to alter the computation of `name` from `pname`, by explaining how to display version numbers,
+* `namePrefix` (optional, defaults to `[ "coq" ]`), provides a way to alter the computation of `name` from `pname`, by explaining which dependencies must occur in `name`,
+* `nativeBuildInputs` (optional), is a list of executables that are required to build the current derivation, in addition to the default ones (namely `which`, `dune` and `ocaml` depending on whether `useDune2`, `useDune2ifVersion` and `mlPlugin` are set).
+* `extraNativeBuildInputs` (optional, deprecated), an additional list of derivation to add to `nativeBuildInputs`,
+* `overrideNativeBuildInputs` (optional) replaces the default list of derivation to which `nativeBuildInputs` and `extraNativeBuildInputs` adds extra elements,
+* `buildInputs` (optional), is a list of libraries and dependencies that are required to build and run the current derivation, in addition to the default one `[ coq ]`,
+* `extraBuildInputs` (optional, deprecated), an additional list of derivation to add to `buildInputs`,
+* `overrideBuildInputs` (optional) replaces the default list of derivation to which `buildInputs` and `extraBuildInputs` adds extras elements,
+* `propagatedBuildInputs` (optional) is passed as is to `mkDerivation`, we recommend to use this for Coq libraries and Coq plugin dependencies, as this makes sure the paths of the compiled libraries and plugins will always be added to the build environements of subsequent derivation, which is necessary for Coq packages to work correctly,
+* `mlPlugin` (optional, defaults to `false`). Some extensions (plugins) might require OCaml and sometimes other OCaml packages. Standard dependencies can be added by setting the current option to `true`. For a finer grain control, the `coq.ocamlPackages` attribute can be used in `nativeBuildInputs`, `buildInputs`, and `propagatedBuildInputs` to depend on the same package set Coq was built against.
+* `useDune2ifVersion` (optional, default to `(x: false)` uses Dune2 to build the package if the provided predicate evaluates to true on the version, e.g. `useDune2ifVersion = versions.isGe "1.1"`  will use dune if the version of the package is greater or equal to `"1.1"`,
+* `useDune2` (optional, defaults to `false`) uses Dune2 to build the package if set to true, the presence of this attribute overrides the behavior of the previous one.
+* `opam-name` (optional, defaults to concatenating with a dash separator the components of `namePrefix` and `pname`), name of the Dune package to build.
+* `enableParallelBuilding` (optional, defaults to `true`), since it is activated by default, we provide a way to disable it.
+* `extraInstallFlags` (optional), allows to extend `installFlags` which initializes the variables `DESTDIR` and `COQMF_COQLIB` so as to install in the proper subdirectory. Indeed Coq libraries should be installed in `$(out)/lib/coq/${coq.coq-version}/user-contrib/`. Such directories are automatically added to the `$COQPATH` environment variable by the hook defined in the Coq derivation.
+* `setCOQBIN` (optional, defaults to `true`), by default, the environment variable `$COQBIN` is set to the current Coq's binary, but one can disable this behavior by setting it to `false`,
+* `useMelquiondRemake` (optional, default to `null`) is an attribute set, which, if given, overloads the `preConfigurePhases`, `configureFlags`, `buildPhase`, and `installPhase` attributes of the derivation for a specific use in libraries using `remake` as set up by Guillaume Melquiond for `flocq`, `gappalib`, `interval`, and `coquelicot` (see the corresponding derivation for concrete examples of use of this option). For backward compatibility, the attribute `useMelquiondRemake.logpath` must be set to the logical root of the library (otherwise, one can pass `useMelquiondRemake = {}` to activate this without backward compatibility).
+* `dropAttrs`, `keepAttrs`, `dropDerivationAttrs` are all optional and allow to tune which attribute is added or removed from the final call to `mkDerivation`.
+
+It also takes other standard `mkDerivation` attributes, they are added as such, except for `meta` which extends an automatically computed `meta` (where the `platform` is the same as `coq` and the homepage is automatically computed).
+
+Here is a simple package example. It is a pure Coq library, thus it depends on Coq. It builds on the Mathematical Components library, thus it also takes some `mathcomp` derivations as `extraBuildInputs`.
+
+```nix
+{ lib, mkCoqDerivation, version ? null
+, coq, mathcomp, mathcomp-finmap, mathcomp-bigenough }:
+with lib; mkCoqDerivation {
+  /* namePrefix leads to e.g. `name = coq8.11-mathcomp1.11-multinomials-1.5.2` */
+  namePrefix = [ "coq" "mathcomp" ];
+  pname = "multinomials";
+  owner = "math-comp";
+  inherit version;
+  defaultVersion =  with versions; switch [ coq.version mathcomp.version ] [
+      { cases = [ (range "8.7" "8.12")  "1.11.0" ];             out = "1.5.2"; }
+      { cases = [ (range "8.7" "8.11")  (range "1.8" "1.10") ]; out = "1.5.0"; }
+      { cases = [ (range "8.7" "8.10")  (range "1.8" "1.10") ]; out = "1.4"; }
+      { cases = [ "8.6"                 (range "1.6" "1.7") ];  out = "1.1"; }
+    ] null;
+  release = {
+    "1.5.2".sha256 = "15aspf3jfykp1xgsxf8knqkxv8aav2p39c2fyirw7pwsfbsv2c4s";
+    "1.5.1".sha256 = "13nlfm2wqripaq671gakz5mn4r0xwm0646araxv0nh455p9ndjs3";
+    "1.5.0".sha256 = "064rvc0x5g7y1a0nip6ic91vzmq52alf6in2bc2dmss6dmzv90hw";
+    "1.5.0".rev    = "1.5";
+    "1.4".sha256   = "0vnkirs8iqsv8s59yx1fvg1nkwnzydl42z3scya1xp1b48qkgn0p";
+    "1.3".sha256   = "0l3vi5n094nx3qmy66hsv867fnqm196r8v605kpk24gl0aa57wh4";
+    "1.2".sha256   = "1mh1w339dslgv4f810xr1b8v2w7rpx6fgk9pz96q0fyq49fw2xcq";
+    "1.1".sha256   = "1q8alsm89wkc0lhcvxlyn0pd8rbl2nnxg81zyrabpz610qqjqc3s";
+    "1.0".sha256   = "1qmbxp1h81cy3imh627pznmng0kvv37k4hrwi2faa101s6bcx55m";
+  };
+
+  propagatedBuildInputs =
+    [ mathcomp.ssreflect mathcomp.algebra mathcomp-finmap mathcomp-bigenough ];
+
+  meta = {
+    description = "A Coq/SSReflect Library for Monoidal Rings and Multinomials";
+    license = licenses.cecill-c;
+  };
+}
+```

doc/languages-frameworks/crystal.section.md

@@ -0,0 +1,73 @@
+# Crystal {#crystal}
+
+## Building a Crystal package {#building-a-crystal-package}
+
+This section uses [Mint](https://github.com/mint-lang/mint) as an example for how to build a Crystal package.
+
+If the Crystal project has any dependencies, the first step is to get a `shards.nix` file encoding those. Get a copy of the project and go to its root directory such that its `shard.lock` file is in the current directory. Executable projects should usually commit the `shard.lock` file, but sometimes that's not the case, which means you need to generate it yourself. With an existing `shard.lock` file, `crystal2nix` can be run.
+```bash
+$ git clone https://github.com/mint-lang/mint
+$ cd mint
+$ git checkout 0.5.0
+$ if [ ! -f shard.lock ]; then nix-shell -p shards --run "shards lock"; fi
+$ nix-shell -p crystal2nix --run crystal2nix
+```
+
+This should have generated a `shards.nix` file.
+
+Next create a Nix file for your derivation and use `pkgs.crystal.buildCrystalPackage` as follows:
+
+```nix
+with import <nixpkgs> {};
+crystal.buildCrystalPackage rec {
+  pname = "mint";
+  version = "0.5.0";
+
+  src = fetchFromGitHub {
+    owner = "mint-lang";
+    repo = "mint";
+    rev = version;
+    sha256 = "0vxbx38c390rd2ysvbwgh89v2232sh5rbsp3nk9wzb70jybpslvl";
+  };
+
+  # Insert the path to your shards.nix file here
+  shardsFile = ./shards.nix;
+
+  ...
+}
+```
+
+This won't build anything yet, because we haven't told it what files build. We can specify a mapping from binary names to source files with the `crystalBinaries` attribute. The project's compilation instructions should show this. For Mint, the binary is called "mint", which is compiled from the source file `src/mint.cr`, so we'll specify this as follows:
+
+```nix
+  crystalBinaries.mint.src = "src/mint.cr";
+
+  # ...
+```
+
+Additionally you can override the default `crystal build` options (which are currently `--release --progress --no-debug --verbose`) with
+
+```nix
+  crystalBinaries.mint.options = [ "--release" "--verbose" ];
+```
+
+Depending on the project, you might need additional steps to get it to compile successfully. In Mint's case, we need to link against openssl, so in the end the Nix file looks as follows:
+
+```nix
+with import <nixpkgs> {};
+crystal.buildCrystalPackage rec {
+  version = "0.5.0";
+  pname = "mint";
+  src = fetchFromGitHub {
+    owner = "mint-lang";
+    repo = "mint";
+    rev = version;
+    sha256 = "0vxbx38c390rd2ysvbwgh89v2232sh5rbsp3nk9wzb70jybpslvl";
+  };
+
+  shardsFile = ./shards.nix;
+  crystalBinaries.mint.src = "src/mint.cr";
+
+  buildInputs = [ openssl ];
+}
+```

doc/languages-frameworks/cuda.section.md

@@ -0,0 +1,34 @@
+# CUDA {#cuda}
+
+CUDA-only packages are stored in the `cudaPackages` packages set. This set
+includes the `cudatoolkit`, portions of the toolkit in separate derivations,
+`cudnn`, `cutensor` and `nccl`.
+
+A package set is available for each CUDA version, so for example
+`cudaPackages_11_6`. Within each set is a matching version of the above listed
+packages. Additionally, other versions of the packages that are packaged and
+compatible are available as well. For example, there can be a
+`cudaPackages.cudnn_8_3_2` package.
+
+To use one or more CUDA packages in an expression, give the expression a `cudaPackages` parameter, and in case CUDA is optional
+```nix
+cudaSupport ? false
+cudaPackages ? {}
+```
+
+When using `callPackage`, you can choose to pass in a different variant, e.g.
+when a different version of the toolkit suffices
+```nix
+mypkg = callPackage { cudaPackages = cudaPackages_11_5; }
+```
+
+If another version of say `cudnn` or `cutensor` is needed, you can override the
+package set to make it the default. This guarantees you get a consistent package
+set.
+```nix
+mypkg = let
+  cudaPackages = cudaPackages_11_5.overrideScope' (final: prev {
+    cudnn = prev.cudnn_8_3_2;
+  }});
+in callPackage { inherit cudaPackages; };
+```

doc/languages-frameworks/dhall.section.md

@@ -0,0 +1,463 @@
+# Dhall {#sec-language-dhall}
+
+The Nixpkgs support for Dhall assumes some familiarity with Dhall's language
+support for importing Dhall expressions, which is documented here:
+
+* [`dhall-lang.org` - Installing packages](https://docs.dhall-lang.org/tutorials/Language-Tour.html#installing-packages)
+
+## Remote imports {#ssec-dhall-remote-imports}
+
+Nixpkgs bypasses Dhall's support for remote imports using Dhall's
+semantic integrity checks.  Specifically, any Dhall import can be protected by
+an integrity check like:
+
+```dhall
+https://prelude.dhall-lang.org/v20.1.0/package.dhall
+  sha256:26b0ef498663d269e4dc6a82b0ee289ec565d683ef4c00d0ebdd25333a5a3c98
+```
+
+… and if the import is cached then the interpreter will load the import from
+cache instead of fetching the URL.
+
+Nixpkgs uses this trick to add all of a Dhall expression's dependencies into the
+cache so that the Dhall interpreter never needs to resolve any remote URLs.  In
+fact, Nixpkgs uses a Dhall interpreter with remote imports disabled when
+packaging Dhall expressions to enforce that the interpreter never resolves a
+remote import.  This means that Nixpkgs only supports building Dhall expressions
+if all of their remote imports are protected by semantic integrity checks.
+
+Instead of remote imports, Nixpkgs uses Nix to fetch remote Dhall code.  For
+example, the Prelude Dhall package uses `pkgs.fetchFromGitHub` to fetch the
+`dhall-lang` repository containing the Prelude.  Relying exclusively on Nix
+to fetch Dhall code ensures that Dhall packages built using Nix remain pure and
+also behave well when built within a sandbox.
+
+## Packaging a Dhall expression from scratch {#ssec-dhall-packaging-expression}
+
+We can illustrate how Nixpkgs integrates Dhall by beginning from the following
+trivial Dhall expression with one dependency (the Prelude):
+
+```dhall
+-- ./true.dhall
+
+let Prelude = https://prelude.dhall-lang.org/v20.1.0/package.dhall
+
+in  Prelude.Bool.not False
+```
+
+As written, this expression cannot be built using Nixpkgs because the
+expression does not protect the Prelude import with a semantic integrity
+check, so the first step is to freeze the expression using `dhall freeze`,
+like this:
+
+```ShellSession
+$ dhall freeze --inplace ./true.dhall
+```
+
+… which gives us:
+
+```dhall
+-- ./true.dhall
+
+let Prelude =
+      https://prelude.dhall-lang.org/v20.1.0/package.dhall
+        sha256:26b0ef498663d269e4dc6a82b0ee289ec565d683ef4c00d0ebdd25333a5a3c98
+
+in  Prelude.Bool.not False
+```
+
+To package that expression, we create a `./true.nix` file containing the
+following specification for the Dhall package:
+
+```nix
+# ./true.nix
+
+{ buildDhallPackage, Prelude }:
+
+buildDhallPackage {
+  name = "true";
+  code = ./true.dhall;
+  dependencies = [ Prelude ];
+  source = true;
+}
+```
+
+… and we complete the build by incorporating that Dhall package into the
+`pkgs.dhallPackages` hierarchy using an overlay, like this:
+
+```nix
+# ./example.nix
+
+let
+  nixpkgs = builtins.fetchTarball {
+    url    = "https://github.com/NixOS/nixpkgs/archive/94b2848559b12a8ed1fe433084686b2a81123c99.tar.gz";
+    sha256 = "1pbl4c2dsaz2lximgd31m96jwbps6apn3anx8cvvhk1gl9rkg107";
+  };
+
+  dhallOverlay = self: super: {
+    true = self.callPackage ./true.nix { };
+  };
+
+  overlay = self: super: {
+    dhallPackages = super.dhallPackages.override (old: {
+      overrides =
+        self.lib.composeExtensions (old.overrides or (_: _: {})) dhallOverlay;
+    });
+  };
+
+  pkgs = import nixpkgs { config = {}; overlays = [ overlay ]; };
+
+in
+  pkgs
+```
+
+… which we can then build using this command:
+
+```ShellSession
+$ nix build --file ./example.nix dhallPackages.true
+```
+
+## Contents of a Dhall package {#ssec-dhall-package-contents}
+
+The above package produces the following directory tree:
+
+```ShellSession
+$ tree -a ./result
+result
+├── .cache
+│   └── dhall
+│       └── 122027abdeddfe8503496adeb623466caa47da5f63abd2bc6fa19f6cfcb73ecfed70
+├── binary.dhall
+└── source.dhall
+```
+
+… where:
+
+* `source.dhall` contains the result of interpreting our Dhall package:
+
+  ```ShellSession
+  $ cat ./result/source.dhall
+  True
+  ```
+
+* The `.cache` subdirectory contains one binary cache product encoding the
+  same result as `source.dhall`:
+
+  ```ShellSession
+  $ dhall decode < ./result/.cache/dhall/122027abdeddfe8503496adeb623466caa47da5f63abd2bc6fa19f6cfcb73ecfed70
+  True
+  ```
+
+* `binary.dhall` contains a Dhall expression which handles fetching and decoding
+  the same cache product:
+
+  ```ShellSession
+  $ cat ./result/binary.dhall
+  missing sha256:27abdeddfe8503496adeb623466caa47da5f63abd2bc6fa19f6cfcb73ecfed70
+  $ cp -r ./result/.cache .cache
+
+  $ chmod -R u+w .cache
+
+  $ XDG_CACHE_HOME=.cache dhall --file ./result/binary.dhall
+  True
+  ```
+
+The `source.dhall` file is only present for packages that specify
+`source = true;`.  By default, Dhall packages omit the `source.dhall` in order
+to conserve disk space when they are used exclusively as dependencies.  For
+example, if we build the Prelude package it will only contain the binary
+encoding of the expression:
+
+```ShellSession
+$ nix build --file ./example.nix dhallPackages.Prelude
+
+$ tree -a result
+result
+├── .cache
+│   └── dhall
+│       └── 122026b0ef498663d269e4dc6a82b0ee289ec565d683ef4c00d0ebdd25333a5a3c98
+└── binary.dhall
+
+2 directories, 2 files
+```
+
+Typically, you only specify `source = true;` for the top-level Dhall expression
+of interest (such as our example `true.nix` Dhall package).  However, if you
+wish to specify `source = true` for all Dhall packages, then you can amend the
+Dhall overlay like this:
+
+```nix
+  dhallOverrides = self: super: {
+    # Enable source for all Dhall packages
+    buildDhallPackage =
+      args: super.buildDhallPackage (args // { source = true; });
+
+    true = self.callPackage ./true.nix { };
+  };
+```
+
+… and now the Prelude will contain the fully decoded result of interpreting
+the Prelude:
+
+```ShellSession
+$ nix build --file ./example.nix dhallPackages.Prelude
+
+$ tree -a result
+result
+├── .cache
+│   └── dhall
+│       └── 122026b0ef498663d269e4dc6a82b0ee289ec565d683ef4c00d0ebdd25333a5a3c98
+├── binary.dhall
+└── source.dhall
+
+$ cat ./result/source.dhall
+{ Bool =
+  { and =
+      \(_ : List Bool) ->
+        List/fold Bool _ Bool (\(_ : Bool) -> \(_ : Bool) -> _@1 && _) True
+  , build = \(_ : Type -> _ -> _@1 -> _@2) -> _ Bool True False
+  , even =
+      \(_ : List Bool) ->
+        List/fold Bool _ Bool (\(_ : Bool) -> \(_ : Bool) -> _@1 == _) True
+  , fold =
+      \(_ : Bool) ->
+…
+```
+
+## Packaging functions {#ssec-dhall-packaging-functions}
+
+We already saw an example of using `buildDhallPackage` to create a Dhall
+package from a single file, but most Dhall packages consist of more than one
+file and there are two derived utilities that you may find more useful when
+packaging multiple files:
+
+* `buildDhallDirectoryPackage` - build a Dhall package from a local directory
+
+* `buildDhallGitHubPackage` - build a Dhall package from a GitHub repository
+
+The `buildDhallPackage` is the lowest-level function and accepts the following
+arguments:
+
+* `name`: The name of the derivation
+
+* `dependencies`: Dhall dependencies to build and cache ahead of time
+
+* `code`: The top-level expression to build for this package
+
+  Note that the `code` field accepts an arbitrary Dhall expression.  You're
+  not limited to just a file.
+
+* `source`: Set to `true` to include the decoded result as `source.dhall` in the
+  build product, at the expense of requiring more disk space
+
+* `documentationRoot`: Set to the root directory of the package if you want
+  `dhall-docs` to generate documentation underneath the `docs` subdirectory of
+  the build product
+
+The `buildDhallDirectoryPackage` is a higher-level function implemented in terms
+of `buildDhallPackage` that accepts the following arguments:
+
+* `name`: Same as `buildDhallPackage`
+
+* `dependencies`: Same as `buildDhallPackage`
+
+* `source`: Same as `buildDhallPackage`
+
+* `src`: The directory containing Dhall code that you want to turn into a Dhall
+  package
+
+* `file`: The top-level file (`package.dhall` by default) that is the entrypoint
+  to the rest of the package
+
+* `document`: Set to `true` to generate documentation for the package
+
+The `buildDhallGitHubPackage` is another higher-level function implemented in
+terms of `buildDhallPackage` that accepts the following arguments:
+
+* `name`: Same as `buildDhallPackage`
+
+* `dependencies`: Same as `buildDhallPackage`
+
+* `source`: Same as `buildDhallPackage`
+
+* `owner`: The owner of the repository
+
+* `repo`: The repository name
+
+* `rev`: The desired revision (or branch, or tag)
+
+* `directory`: The subdirectory of the Git repository to package (if a
+  directory other than the root of the repository)
+
+* `file`: The top-level file (`${directory}/package.dhall` by default) that is
+  the entrypoint to the rest of the package
+
+* `document`: Set to `true` to generate documentation for the package
+
+Additionally, `buildDhallGitHubPackage` accepts the same arguments as
+`fetchFromGitHub`, such as `sha256` or `fetchSubmodules`.
+
+## `dhall-to-nixpkgs` {#ssec-dhall-dhall-to-nixpkgs}
+
+You can use the `dhall-to-nixpkgs` command-line utility to automate
+packaging Dhall code.  For example:
+
+```ShellSession
+$ nix-env --install --attr haskellPackages.dhall-nixpkgs
+
+$ nix-env --install --attr nix-prefetch-git  # Used by dhall-to-nixpkgs
+
+$ dhall-to-nixpkgs github https://github.com/Gabriel439/dhall-semver.git
+{ buildDhallGitHubPackage, Prelude }:
+  buildDhallGitHubPackage {
+    name = "dhall-semver";
+    githubBase = "github.com";
+    owner = "Gabriel439";
+    repo = "dhall-semver";
+    rev = "2d44ae605302ce5dc6c657a1216887fbb96392a4";
+    fetchSubmodules = false;
+    sha256 = "0y8shvp8srzbjjpmnsvz9c12ciihnx1szs0yzyi9ashmrjvd0jcz";
+    directory = "";
+    file = "package.dhall";
+    source = false;
+    document = false;
+    dependencies = [ (Prelude.overridePackage { file = "package.dhall"; }) ];
+    }
+```
+
+The utility takes care of automatically detecting remote imports and converting
+them to package dependencies.  You can also use the utility on local
+Dhall directories, too:
+
+```ShellSession
+$ dhall-to-nixpkgs directory ~/proj/dhall-semver
+{ buildDhallDirectoryPackage, Prelude }:
+  buildDhallDirectoryPackage {
+    name = "proj";
+    src = ~/proj/dhall-semver;
+    file = "package.dhall";
+    source = false;
+    document = false;
+    dependencies = [ (Prelude.overridePackage { file = "package.dhall"; }) ];
+    }
+```
+
+### Remote imports as fixed-output derivations {#ssec-dhall-remote-imports-as-fod}
+
+`dhall-to-nixpkgs` has the ability to fetch and build remote imports as
+fixed-output derivations by using their Dhall integrity check. This is
+sometimes easier than manually packaging all remote imports.
+
+This can be used like the following:
+
+```ShellSession
+$ dhall-to-nixpkgs directory --fixed-output-derivations ~/proj/dhall-semver
+{ buildDhallDirectoryPackage, buildDhallUrl }:
+  buildDhallDirectoryPackage {
+    name = "proj";
+    src = ~/proj/dhall-semver;
+    file = "package.dhall";
+    source = false;
+    document = false;
+    dependencies = [
+      (buildDhallUrl {
+        url = "https://prelude.dhall-lang.org/v17.0.0/package.dhall";
+        hash = "sha256-ENs8kZwl6QRoM9+Jeo/+JwHcOQ+giT2VjDQwUkvlpD4=";
+        dhallHash = "sha256:10db3c919c25e9046833df897a8ffe2701dc390fa0893d958c3430524be5a43e";
+        })
+      ];
+    }
+```
+
+Here, `dhall-semver`'s `Prelude` dependency is fetched and built with the
+`buildDhallUrl` helper function, instead of being passed in as a function
+argument.
+
+## Overriding dependency versions {#ssec-dhall-overriding-dependency-versions}
+
+Suppose that we change our `true.dhall` example expression to depend on an older
+version of the Prelude (19.0.0):
+
+```dhall
+-- ./true.dhall
+
+let Prelude =
+      https://prelude.dhall-lang.org/v19.0.0/package.dhall
+        sha256:eb693342eb769f782174157eba9b5924cf8ac6793897fc36a31ccbd6f56dafe2
+
+in  Prelude.Bool.not False
+```
+
+If we try to rebuild that expression the build will fail:
+
+```ShellSession
+$ nix build --file ./example.nix dhallPackages.true
+builder for '/nix/store/0f1hla7ff1wiaqyk1r2ky4wnhnw114fi-true.drv' failed with exit code 1; last 10 log lines:
+
+  Dhall was compiled without the 'with-http' flag.
+
+  The requested URL was: https://prelude.dhall-lang.org/v19.0.0/package.dhall
+
+
+  4│       https://prelude.dhall-lang.org/v19.0.0/package.dhall
+  5│         sha256:eb693342eb769f782174157eba9b5924cf8ac6793897fc36a31ccbd6f56dafe2
+
+  /nix/store/rsab4y99h14912h4zplqx2iizr5n4rc2-true.dhall:4:7
+[1 built (1 failed), 0.0 MiB DL]
+error: build of '/nix/store/0f1hla7ff1wiaqyk1r2ky4wnhnw114fi-true.drv' failed
+```
+
+… because the default Prelude selected by Nixpkgs revision
+`94b2848559b12a8ed1fe433084686b2a81123c99is` is version 20.1.0, which doesn't
+have the same integrity check as version 19.0.0.  This means that version
+19.0.0 is not cached and the interpreter is not allowed to fall back to
+importing the URL.
+
+However, we can override the default Prelude version by using `dhall-to-nixpkgs`
+to create a Dhall package for our desired Prelude:
+
+```ShellSession
+$ dhall-to-nixpkgs github https://github.com/dhall-lang/dhall-lang.git \
+    --name Prelude \
+    --directory Prelude \
+    --rev v19.0.0 \
+    > Prelude.nix
+```
+
+… and then referencing that package in our Dhall overlay, by either overriding
+the Prelude globally for all packages, like this:
+
+```nix
+  dhallOverrides = self: super: {
+    true = self.callPackage ./true.nix { };
+
+    Prelude = self.callPackage ./Prelude.nix { };
+  };
+```
+
+… or selectively overriding the Prelude dependency for just the `true` package,
+like this:
+
+```nix
+  dhallOverrides = self: super: {
+    true = self.callPackage ./true.nix {
+      Prelude = self.callPackage ./Prelude.nix { };
+    };
+  };
+```
+
+## Overrides {#ssec-dhall-overrides}
+
+You can override any of the arguments to `buildDhallGitHubPackage` or
+`buildDhallDirectoryPackage` using the `overridePackage` attribute of a package.
+For example, suppose we wanted to selectively enable `source = true` just for the Prelude.  We can do that like this:
+
+```nix
+  dhallOverrides = self: super: {
+    Prelude = super.Prelude.overridePackage { source = true; };
+
+    …
+  };
+```
+
+[semantic-integrity-checks]: https://docs.dhall-lang.org/tutorials/Language-Tour.html#installing-packages

doc/languages-frameworks/dotnet.section.md

@@ -0,0 +1,132 @@
+# Dotnet {#dotnet}
+
+## Local Development Workflow {#local-development-workflow}
+
+For local development, it's recommended to use nix-shell to create a dotnet environment:
+
+```nix
+# shell.nix
+with import <nixpkgs> {};
+
+mkShell {
+  name = "dotnet-env";
+  packages = [
+    dotnet-sdk_3
+  ];
+}
+```
+
+### Using many sdks in a workflow {#using-many-sdks-in-a-workflow}
+
+It's very likely that more than one sdk will be needed on a given project. Dotnet provides several different frameworks (E.g dotnetcore, aspnetcore, etc.) as well as many versions for a given framework. Normally, dotnet is able to fetch a framework and install it relative to the executable. However, this would mean writing to the nix store in nixpkgs, which is read-only. To support the many-sdk use case, one can compose an environment using `dotnetCorePackages.combinePackages`:
+
+```nix
+with import <nixpkgs> {};
+
+mkShell {
+  name = "dotnet-env";
+  packages = [
+    (with dotnetCorePackages; combinePackages [
+      sdk_3_1
+      sdk_5_0
+    ])
+  ];
+}
+```
+
+This will produce a dotnet installation that has the dotnet 3.1, 3.0, and 2.1 sdk. The first sdk listed will have it's cli utility present in the resulting environment. Example info output:
+
+```ShellSession
+$ dotnet --info
+.NET Core SDK (reflecting any global.json):
+ Version:   3.1.101
+ Commit:    b377529961
+
+...
+
+.NET Core SDKs installed:
+  2.1.803 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/sdk]
+  3.0.102 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/sdk]
+  3.1.101 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/sdk]
+
+.NET Core runtimes installed:
+  Microsoft.AspNetCore.All 2.1.15 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.AspNetCore.All]
+  Microsoft.AspNetCore.App 2.1.15 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.AspNetCore.App]
+  Microsoft.AspNetCore.App 3.0.2 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.AspNetCore.App]
+  Microsoft.AspNetCore.App 3.1.1 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.AspNetCore.App]
+  Microsoft.NETCore.App 2.1.15 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.NETCore.App]
+  Microsoft.NETCore.App 3.0.2 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.NETCore.App]
+  Microsoft.NETCore.App 3.1.1 [/nix/store/iiv98i2jdi226dgh4jzkkj2ww7f8jgpd-dotnet-core-combined/shared/Microsoft.NETCore.App]
+```
+
+## dotnet-sdk vs dotnetCorePackages.sdk {#dotnet-sdk-vs-dotnetcorepackages.sdk}
+
+The `dotnetCorePackages.sdk_X_Y` is preferred over the old dotnet-sdk as both major and minor version are very important for a dotnet environment. If a given minor version isn't present (or was changed), then this will likely break your ability to build a project.
+
+## dotnetCorePackages.sdk vs dotnetCorePackages.runtime vs dotnetCorePackages.aspnetcore {#dotnetcorepackages.sdk-vs-dotnetcorepackages.runtime-vs-dotnetcorepackages.aspnetcore}
+
+The `dotnetCorePackages.sdk` contains both a runtime and the full sdk of a given version. The `runtime` and `aspnetcore` packages are meant to serve as minimal runtimes to deploy alongside already built applications.
+
+## Packaging a Dotnet Application {#packaging-a-dotnet-application}
+
+To package Dotnet applications, you can use `buildDotnetModule`. This has similar arguments to `stdenv.mkDerivation`, with the following additions:
+
+* `projectFile` has to be used for specifying the dotnet project file relative to the source root. These usually have `.sln` or `.csproj` file extensions. This can be an array of multiple projects as well.
+* `nugetDeps` has to be used to specify the NuGet dependency file. Unfortunately, these cannot be deterministically fetched without a lockfile. A script to fetch these is available as `passthru.fetch-deps`. This file can also be generated manually using `nuget-to-nix` tool, which is available in nixpkgs.
+* `packNupkg` is used to pack project as a `nupkg`, and installs it to `$out/share`. If set to `true`, the derivation can be used as a dependency for another dotnet project by adding it to `projectReferences`.
+* `projectReferences` can be used to resolve `ProjectReference` project items. Referenced projects can be packed with `buildDotnetModule` by setting the `packNupkg = true` attribute and passing a list of derivations to `projectReferences`. Since we are sharing referenced projects as NuGets they must be added to csproj/fsproj files as `PackageReference` as well.
+ For example, your project has a local dependency:
+ ```xml
+     <ProjectReference Include="../foo/bar.fsproj" />
+ ```
+ To enable discovery through `projectReferences` you would need to add:
+ ```xml
+     <ProjectReference Include="../foo/bar.fsproj" />
+     <PackageReference Include="bar" Version="*" Condition=" '$(ContinuousIntegrationBuild)'=='true' "/>
+  ```
+* `executables` is used to specify which executables get wrapped to `$out/bin`, relative to `$out/lib/$pname`. If this is unset, all executables generated will get installed. If you do not want to install any, set this to `[]`. This gets done in the `preFixup` phase.
+* `runtimeDeps` is used to wrap libraries into `LD_LIBRARY_PATH`. This is how dotnet usually handles runtime dependencies.
+* `buildType` is used to change the type of build. Possible values are `Release`, `Debug`, etc. By default, this is set to `Release`.
+* `dotnet-sdk` is useful in cases where you need to change what dotnet SDK is being used.
+* `dotnet-runtime` is useful in cases where you need to change what dotnet runtime is being used. This can be either a regular dotnet runtime, or an aspnetcore.
+* `dotnet-test-sdk` is useful in cases where unit tests expect a different dotnet SDK. By default, this is set to the `dotnet-sdk` attribute.
+* `testProjectFile` is useful in cases where the regular project file does not contain the unit tests. It gets restored and build, but not installed. You may need to regenerate your nuget lockfile after setting this.
+* `disabledTests` is used to disable running specific unit tests. This gets passed as: `dotnet test --filter "FullyQualifiedName!={}"`, to ensure compatibility with all unit test frameworks.
+* `dotnetRestoreFlags` can be used to pass flags to `dotnet restore`.
+* `dotnetBuildFlags` can be used to pass flags to `dotnet build`.
+* `dotnetTestFlags` can be used to pass flags to `dotnet test`. Used only if `doCheck` is set to `true`.
+* `dotnetInstallFlags` can be used to pass flags to `dotnet install`.
+* `dotnetPackFlags` can be used to pass flags to `dotnet pack`. Used only if `packNupkg` is set to `true`.
+* `dotnetFlags` can be used to pass flags to all of the above phases.
+
+When packaging a new application, you need to fetch it's dependencies. You can set `nugetDeps` to an empty string to make the derivation temporarily evaluate, and then run `nix-build -A package.passthru.fetch-deps` to generate it's dependency fetching script. After running the script, you should have the location of the generated lockfile printed to the console. This can be copied to a stable directory. Note that if either `projectFile` or `nugetDeps` are unset, this script cannot be generated!
+
+Here is an example `default.nix`, using some of the previously discussed arguments:
+```nix
+{ lib, buildDotnetModule, dotnetCorePackages, ffmpeg }:
+
+let
+  referencedProject = import ../../bar { ... };
+in buildDotnetModule rec {
+  pname = "someDotnetApplication";
+  version = "0.1";
+
+  src = ./.;
+
+  projectFile = "src/project.sln";
+  nugetDeps = ./deps.nix; # File generated with `nix-build -A package.passthru.fetch-deps`.
+
+  projectReferences = [ referencedProject ]; # `referencedProject` must contain `nupkg` in the folder structure.
+
+  dotnet-sdk = dotnetCorePackages.sdk_3_1;
+  dotnet-runtime = dotnetCorePackages.net_5_0;
+  dotnetFlags = [ "--runtime linux-x64" ];
+
+  executables = [ "foo" ]; # This wraps "$out/lib/$pname/foo" to `$out/bin/foo`.
+  executables = []; # Don't install any executables.
+
+  packNupkg = true; # This packs the project as "foo-0.1.nupkg" at `$out/share`.
+
+  runtimeDeps = [ ffmpeg ]; # This will wrap ffmpeg's library path into `LD_LIBRARY_PATH`.
+}
+```

doc/languages-frameworks/emscripten.section.md

@@ -0,0 +1,182 @@
+# Emscripten {#emscripten}
+
+[Emscripten](https://github.com/kripken/emscripten): An LLVM-to-JavaScript Compiler
+
+This section of the manual covers how to use `emscripten` in nixpkgs.
+
+Minimal requirements:
+
+* nix
+* nixpkgs
+
+Modes of use of `emscripten`:
+
+* **Imperative usage** (on the command line):
+
+   If you want to work with `emcc`, `emconfigure` and `emmake` as you are used to from Ubuntu and similar distributions you can use these commands:
+
+    * `nix-env -f "<nixpkgs>" -iA emscripten`
+    * `nix-shell -p emscripten`
+
+* **Declarative usage**:
+
+    This mode is far more power full since this makes use of `nix` for dependency management of emscripten libraries and targets by using the `mkDerivation` which is implemented by `pkgs.emscriptenStdenv` and `pkgs.buildEmscriptenPackage`. The source for the packages is in `pkgs/top-level/emscripten-packages.nix` and the abstraction behind it in `pkgs/development/em-modules/generic/default.nix`. From the root of the nixpkgs repository:
+    * build and install all packages:
+        * `nix-env -iA emscriptenPackages`
+
+    * dev-shell for zlib implementation hacking:
+        * `nix-shell -A emscriptenPackages.zlib`
+
+## Imperative usage {#imperative-usage}
+
+A few things to note:
+
+* `export EMCC_DEBUG=2` is nice for debugging
+* `~/.emscripten`, the build artifact cache sometimes creates issues and needs to be removed from time to time
+
+## Declarative usage {#declarative-usage}
+
+Let's see two different examples from `pkgs/top-level/emscripten-packages.nix`:
+
+* `pkgs.zlib.override`
+* `pkgs.buildEmscriptenPackage`
+
+Both are interesting concepts.
+
+A special requirement of the `pkgs.buildEmscriptenPackage` is the `doCheck = true` is a default meaning that each emscriptenPackage requires a `checkPhase` implemented.
+
+* Use `export EMCC_DEBUG=2` from within a emscriptenPackage's `phase` to get more detailed debug output what is going wrong.
+* ~/.emscripten cache is requiring us to set `HOME=$TMPDIR` in individual phases. This makes compilation slower but also makes it more deterministic.
+
+### Usage 1: pkgs.zlib.override {#usage-1-pkgs.zlib.override}
+
+This example uses `zlib` from nixpkgs but instead of compiling **C** to **ELF** it compiles **C** to **JS** since we were using `pkgs.zlib.override` and changed stdenv to `pkgs.emscriptenStdenv`. A few adaptions and hacks were set in place to make it working. One advantage is that when `pkgs.zlib` is updated, it will automatically update this package as well. However, this can also be the downside...
+
+See the `zlib` example:
+
+    zlib = (pkgs.zlib.override {
+      stdenv = pkgs.emscriptenStdenv;
+    }).overrideDerivation
+    (old: rec {
+      buildInputs = old.buildInputs ++ [ pkg-config ];
+      # we need to reset this setting!
+      NIX_CFLAGS_COMPILE="";
+      configurePhase = ''
+        # FIXME: Some tests require writing at $HOME
+        HOME=$TMPDIR
+        runHook preConfigure
+
+        #export EMCC_DEBUG=2
+        emconfigure ./configure --prefix=$out --shared
+
+        runHook postConfigure
+      '';
+      dontStrip = true;
+      outputs = [ "out" ];
+      buildPhase = ''
+        emmake make
+      '';
+      installPhase = ''
+        emmake make install
+      '';
+      checkPhase = ''
+        echo "================= testing zlib using node ================="
+
+        echo "Compiling a custom test"
+        set -x
+        emcc -O2 -s EMULATE_FUNCTION_POINTER_CASTS=1 test/example.c -DZ_SOLO \
+        libz.so.${old.version} -I . -o example.js
+
+        echo "Using node to execute the test"
+        ${pkgs.nodejs}/bin/node ./example.js
+
+        set +x
+        if [ $? -ne 0 ]; then
+          echo "test failed for some reason"
+          exit 1;
+        else
+          echo "it seems to work! very good."
+        fi
+        echo "================= /testing zlib using node ================="
+      '';
+
+      postPatch = pkgs.lib.optionalString pkgs.stdenv.isDarwin ''
+        substituteInPlace configure \
+          --replace '/usr/bin/libtool' 'ar' \
+          --replace 'AR="libtool"' 'AR="ar"' \
+          --replace 'ARFLAGS="-o"' 'ARFLAGS="-r"'
+      '';
+    });
+
+### Usage 2: pkgs.buildEmscriptenPackage {#usage-2-pkgs.buildemscriptenpackage}
+
+This `xmlmirror` example features a emscriptenPackage which is defined completely from this context and no `pkgs.zlib.override` is used.
+
+    xmlmirror = pkgs.buildEmscriptenPackage rec {
+      name = "xmlmirror";
+
+      buildInputs = [ pkg-config autoconf automake libtool gnumake libxml2 nodejs openjdk json_c ];
+      nativeBuildInputs = [ pkg-config zlib ];
+
+      src = pkgs.fetchgit {
+        url = "https://gitlab.com/odfplugfest/xmlmirror.git";
+        rev = "4fd7e86f7c9526b8f4c1733e5c8b45175860a8fd";
+        sha256 = "1jasdqnbdnb83wbcnyrp32f36w3xwhwp0wq8lwwmhqagxrij1r4b";
+      };
+
+      configurePhase = ''
+        rm -f fastXmlLint.js*
+        # a fix for ERROR:root:For asm.js, TOTAL_MEMORY must be a multiple of 16MB, was 234217728
+        # https://gitlab.com/odfplugfest/xmlmirror/issues/8
+        sed -e "s/TOTAL_MEMORY=234217728/TOTAL_MEMORY=268435456/g" -i Makefile.emEnv
+        # https://github.com/kripken/emscripten/issues/6344
+        # https://gitlab.com/odfplugfest/xmlmirror/issues/9
+        sed -e "s/\$(JSONC_LDFLAGS) \$(ZLIB_LDFLAGS) \$(LIBXML20_LDFLAGS)/\$(JSONC_LDFLAGS) \$(LIBXML20_LDFLAGS) \$(ZLIB_LDFLAGS) /g" -i Makefile.emEnv
+        # https://gitlab.com/odfplugfest/xmlmirror/issues/11
+        sed -e "s/-o fastXmlLint.js/-s EXTRA_EXPORTED_RUNTIME_METHODS='[\"ccall\", \"cwrap\"]' -o fastXmlLint.js/g" -i Makefile.emEnv
+      '';
+
+      buildPhase = ''
+        HOME=$TMPDIR
+        make -f Makefile.emEnv
+      '';
+
+      outputs = [ "out" "doc" ];
+
+      installPhase = ''
+        mkdir -p $out/share
+        mkdir -p $doc/share/${name}
+
+        cp Demo* $out/share
+        cp -R codemirror-5.12 $out/share
+        cp fastXmlLint.js* $out/share
+        cp *.xsd $out/share
+        cp *.js $out/share
+        cp *.xhtml $out/share
+        cp *.html $out/share
+        cp *.json $out/share
+        cp *.rng $out/share
+        cp README.md $doc/share/${name}
+      '';
+      checkPhase = ''
+
+      '';
+    };
+
+### Declarative debugging {#declarative-debugging}
+
+Use `nix-shell -I nixpkgs=/some/dir/nixpkgs -A emscriptenPackages.libz` and from there you can go trough the individual steps. This makes it easy to build a good `unit test` or list the files of the project.
+
+1. `nix-shell -I nixpkgs=/some/dir/nixpkgs -A emscriptenPackages.libz`
+2. `cd /tmp/`
+3. `unpackPhase`
+4. cd libz-1.2.3
+5. `configurePhase`
+6. `buildPhase`
+7. ... happy hacking...
+
+## Summary {#summary}
+
+Using this toolchain makes it easy to leverage `nix` from NixOS, MacOSX or even Windows (WSL+ubuntu+nix). This toolchain is reproducible, behaves like the rest of the packages from nixpkgs and contains a set of well working examples to learn and adapt from.
+
+If in trouble, ask the maintainers.

doc/languages-frameworks/gnome.section.md

@@ -0,0 +1,218 @@
+# GNOME {#sec-language-gnome}
+
+## Packaging GNOME applications {#ssec-gnome-packaging}
+
+Programs in the GNOME universe are written in various languages but they all use GObject-based libraries like GLib, GTK or GStreamer. These libraries are often modular, relying on looking into certain directories to find their modules. However, due to Nix’s specific file system organization, this will fail without our intervention. Fortunately, the libraries usually allow overriding the directories through environment variables, either natively or thanks to a patch in nixpkgs. [Wrapping](#fun-wrapProgram) the executables to ensure correct paths are available to the application constitutes a significant part of packaging a modern desktop application. In this section, we will describe various modules needed by such applications, environment variables needed to make the modules load, and finally a script that will do the work for us.
+
+### Settings {#ssec-gnome-settings}
+
+[GSettings](https://developer.gnome.org/gio/stable/GSettings.html) API is often used for storing settings. GSettings schemas are required, to know the type and other metadata of the stored values. GLib looks for `glib-2.0/schemas/gschemas.compiled` files inside the directories of `XDG_DATA_DIRS`.
+
+On Linux, GSettings API is implemented using [dconf](https://wiki.gnome.org/Projects/dconf) backend. You will need to add `dconf` [GIO module](#ssec-gnome-gio-modules) to `GIO_EXTRA_MODULES` variable, otherwise the `memory` backend will be used and the saved settings will not be persistent.
+
+Last you will need the dconf database D-Bus service itself. You can enable it using `programs.dconf.enable`.
+
+Some applications will also require `gsettings-desktop-schemas` for things like reading proxy configuration or user interface customization. This dependency is often not mentioned by upstream, you should grep for `org.gnome.desktop` and `org.gnome.system` to see if the schemas are needed.
+
+### GIO modules {#ssec-gnome-gio-modules}
+
+GLib’s [GIO](https://developer.gnome.org/gio/stable/ch01.html) library supports several [extension points](https://developer.gnome.org/gio/stable/extending-gio.html). Notably, they allow:
+
+* implementing settings backends (already [mentioned](#ssec-gnome-settings))
+* adding TLS support
+* proxy settings
+* virtual file systems
+
+The modules are typically installed to `lib/gio/modules/` directory of a package and you need to add them to `GIO_EXTRA_MODULES` if you need any of those features.
+
+In particular, we recommend:
+
+* adding `dconf.lib` for any software on Linux that reads [GSettings](#ssec-gnome-settings) (even transitivily through e.g. GTK’s file manager)
+* adding `glib-networking` for any software that accesses network using GIO or libsoup – glib-networking contains a module that implements TLS support and loads system-wide proxy settings
+
+To allow software to use various virtual file systems, `gvfs` package can be also added. But that is usually an optional feature so we typically use `gvfs` from the system (e.g. installed globally using NixOS module).
+
+### GdkPixbuf loaders {#ssec-gnome-gdk-pixbuf-loaders}
+
+GTK applications typically use [GdkPixbuf](https://developer.gnome.org/gdk-pixbuf/stable/) to load images. But `gdk-pixbuf` package only supports basic bitmap formats like JPEG, PNG or TIFF, requiring to use third-party loader modules for other formats. This is especially painful since GTK itself includes SVG icons, which cannot be rendered without a loader provided by `librsvg`.
+
+Unlike other libraries mentioned in this section, GdkPixbuf only supports a single value in its controlling environment variable `GDK_PIXBUF_MODULE_FILE`. It is supposed to point to a cache file containing information about the available loaders. Each loader package will contain a `lib/gdk-pixbuf-2.0/2.10.0/loaders.cache` file describing the default loaders in `gdk-pixbuf` package plus the loader contained in the package itself. If you want to use multiple third-party loaders, you will need to create your own cache file manually. Fortunately, this is pretty rare as [not many loaders exist](https://gitlab.gnome.org/federico/gdk-pixbuf-survey/blob/master/src/modules.md).
+
+`gdk-pixbuf` contains [a setup hook](#ssec-gnome-hooks-gdk-pixbuf) that sets `GDK_PIXBUF_MODULE_FILE` from dependencies but as mentioned in further section, it is pretty limited. Loaders should propagate this setup hook.
+
+### Icons {#ssec-gnome-icons}
+
+When an application uses icons, an icon theme should be available in `XDG_DATA_DIRS` during runtime. The package for the default, icon-less [hicolor-icon-theme](https://www.freedesktop.org/wiki/Software/icon-theme/) (should be propagated by every icon theme) contains [a setup hook](#ssec-gnome-hooks-hicolor-icon-theme) that will pick up icon themes from `buildInputs` and add their datadirs to `XDG_ICON_DIRS` environment variable (this is Nixpkgs specific, not actually a XDG standard variable). Unfortunately, relying on that would mean every user has to download the theme included in the package expression no matter their preference. For that reason, we leave the installation of icon theme on the user. If you use one of the desktop environments, you probably already have an icon theme installed.
+
+In the rare case you need to use icons from dependencies (e.g. when an app forces an icon theme), you can use the following to pick them up:
+
+```nix
+  buildInputs = [
+    pantheon.elementary-icon-theme
+  ];
+  preFixup = ''
+    gappsWrapperArgs+=(
+      # The icon theme is hardcoded.
+      --prefix XDG_DATA_DIRS : "$XDG_ICON_DIRS"
+    )
+  '';
+```
+
+To avoid costly file system access when locating icons, GTK, [as well as Qt](https://woboq.com/blog/qicon-reads-gtk-icon-cache-in-qt57.html), can rely on `icon-theme.cache` files from the themes' top-level directories. These files are generated using `gtk-update-icon-cache`, which is expected to be run whenever an icon is added or removed to an icon theme (typically an application icon into `hicolor` theme) and some programs do indeed run this after icon installation. However, since packages are installed into their own prefix by Nix, this would lead to conflicts. For that reason, `gtk3` provides a [setup hook](#ssec-gnome-hooks-gtk-drop-icon-theme-cache) that will clean the file from installation. Since most applications only ship their own icon that will be loaded on start-up, it should not affect them too much. On the other hand, icon themes are much larger and more widely used so we need to cache them. Because we recommend installing icon themes globally, we will generate the cache files from all packages in a profile using a NixOS module. You can enable the cache generation using `gtk.iconCache.enable` option if your desktop environment does not already do that.
+
+### Packaging icon themes {#ssec-icon-theme-packaging}
+
+Icon themes may inherit from other icon themes. The inheritance is specified using the `Inherits` key in the `index.theme` file distributed with the icon theme. According to the [icon theme specification](https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html), icons not provided by the theme are looked for in its parent icon themes. Therefore the parent themes should be installed as dependencies for a more complete experience regarding the icon sets used.
+
+The package `hicolor-icon-theme` provides a setup hook which makes symbolic links for the parent themes into the directory `share/icons` of the current theme directory in the nix store, making sure they can be found at runtime. For that to work the packages providing parent icon themes should be listed as propagated build dependencies, together with `hicolor-icon-theme`.
+
+Also make sure that `icon-theme.cache` is installed for each theme provided by the package, and set `dontDropIconThemeCache` to `true` so that the cache file is not removed by the `gtk3` setup hook.
+
+### GTK Themes {#ssec-gnome-themes}
+
+Previously, a GTK theme needed to be in `XDG_DATA_DIRS`. This is no longer necessary for most programs since GTK incorporated Adwaita theme. Some programs (for example, those designed for [elementary HIG](https://elementary.io/docs/human-interface-guidelines#human-interface-guidelines)) might require a special theme like `pantheon.elementary-gtk-theme`.
+
+### GObject introspection typelibs {#ssec-gnome-typelibs}
+
+[GObject introspection](https://wiki.gnome.org/Projects/GObjectIntrospection) allows applications to use C libraries in other languages easily. It does this through `typelib` files searched in `GI_TYPELIB_PATH`.
+
+### Various plug-ins {#ssec-gnome-plugins}
+
+If your application uses [GStreamer](https://gstreamer.freedesktop.org/) or [Grilo](https://wiki.gnome.org/Projects/Grilo), you should set `GST_PLUGIN_SYSTEM_PATH_1_0` and `GRL_PLUGIN_PATH`, respectively.
+
+## Onto `wrapGAppsHook` {#ssec-gnome-hooks}
+
+Given the requirements above, the package expression would become messy quickly:
+
+```nix
+preFixup = ''
+  for f in $(find $out/bin/ $out/libexec/ -type f -executable); do
+    wrapProgram "$f" \
+      --prefix GIO_EXTRA_MODULES : "${getLib dconf}/lib/gio/modules" \
+      --prefix XDG_DATA_DIRS : "$out/share" \
+      --prefix XDG_DATA_DIRS : "$out/share/gsettings-schemas/${name}" \
+      --prefix XDG_DATA_DIRS : "${gsettings-desktop-schemas}/share/gsettings-schemas/${gsettings-desktop-schemas.name}" \
+      --prefix XDG_DATA_DIRS : "${hicolor-icon-theme}/share" \
+      --prefix GI_TYPELIB_PATH : "${lib.makeSearchPath "lib/girepository-1.0" [ pango json-glib ]}"
+  done
+'';
+```
+
+Fortunately, there is [`wrapGAppsHook`]{#ssec-gnome-hooks-wrapgappshook}. It works in conjunction with other setup hooks that populate environment variables, and it will then wrap all executables in `bin` and `libexec` directories using said variables.
+
+For convenience, it also adds `dconf.lib` for a GIO module implementing a GSettings backend using `dconf`, `gtk3` for GSettings schemas, and `librsvg` for GdkPixbuf loader to the closure. There is also [`wrapGAppsHook4`]{#ssec-gnome-hooks-wrapgappshook4}, which replaces GTK 3 with GTK 4. And in case you are packaging a program without a graphical interface, you might want to use [`wrapGAppsNoGuiHook`]{#ssec-gnome-hooks-wrapgappsnoguihook}, which runs the same script as `wrapGAppsHook` but does not bring `gtk3` and `librsvg` into the closure.
+
+- `wrapGAppsHook` itself will add the package’s `share` directory to `XDG_DATA_DIRS`.
+
+- []{#ssec-gnome-hooks-glib} `glib` setup hook will populate `GSETTINGS_SCHEMAS_PATH` and then `wrapGAppsHook` will prepend it to `XDG_DATA_DIRS`.
+
+- []{#ssec-gnome-hooks-gdk-pixbuf} `gdk-pixbuf` setup hook will populate `GDK_PIXBUF_MODULE_FILE` with the path to biggest `loaders.cache` file from the dependencies containing [GdkPixbuf loaders](#ssec-gnome-gdk-pixbuf-loaders). This works fine when there are only two packages containing loaders (`gdk-pixbuf` and e.g. `librsvg`) – it will choose the second one, reasonably expecting that it will be bigger since it describes extra loader in addition to the default ones. But when there are more than two loader packages, this logic will break. One possible solution would be constructing a custom cache file for each package containing a program like `services/x11/gdk-pixbuf.nix` NixOS module does. `wrapGAppsHook` copies the `GDK_PIXBUF_MODULE_FILE` environment variable into the produced wrapper.
+
+- []{#ssec-gnome-hooks-gtk-drop-icon-theme-cache} One of `gtk3`’s setup hooks will remove `icon-theme.cache` files from package’s icon theme directories to avoid conflicts. Icon theme packages should prevent this with `dontDropIconThemeCache = true;`.
+
+- []{#ssec-gnome-hooks-dconf} `dconf.lib` is a dependency of `wrapGAppsHook`, which then also adds it to the `GIO_EXTRA_MODULES` variable.
+
+- []{#ssec-gnome-hooks-hicolor-icon-theme} `hicolor-icon-theme`’s setup hook will add icon themes to `XDG_ICON_DIRS`.
+
+- []{#ssec-gnome-hooks-gobject-introspection} `gobject-introspection` setup hook populates `GI_TYPELIB_PATH` variable with `lib/girepository-1.0` directories of dependencies, which is then added to wrapper by `wrapGAppsHook`. It also adds `share` directories of dependencies to `XDG_DATA_DIRS`, which is intended to promote GIR files but it also [pollutes the closures](https://github.com/NixOS/nixpkgs/issues/32790) of packages using `wrapGAppsHook`.
+
+  ::: {.warning}
+  The setup hook [currently](https://github.com/NixOS/nixpkgs/issues/56943) does not work in expressions with `strictDeps` enabled, like Python packages. In those cases, you will need to disable it with `strictDeps = false;`.
+  :::
+
+- []{#ssec-gnome-hooks-gst-grl-plugins} Setup hooks of `gst_all_1.gstreamer` and `grilo` will populate the `GST_PLUGIN_SYSTEM_PATH_1_0` and `GRL_PLUGIN_PATH` variables, respectively, which will then be added to the wrapper by `wrapGAppsHook`.
+
+You can also pass additional arguments to `makeWrapper` using `gappsWrapperArgs` in `preFixup` hook:
+
+```nix
+preFixup = ''
+  gappsWrapperArgs+=(
+    # Thumbnailers
+    --prefix XDG_DATA_DIRS : "${gdk-pixbuf}/share"
+    --prefix XDG_DATA_DIRS : "${librsvg}/share"
+    --prefix XDG_DATA_DIRS : "${shared-mime-info}/share"
+  )
+'';
+```
+
+## Updating GNOME packages {#ssec-gnome-updating}
+
+Most GNOME package offer [`updateScript`](#var-passthru-updateScript), it is therefore possible to update to latest source tarball by running `nix-shell maintainers/scripts/update.nix --argstr package gnome.nautilus` or even en masse with `nix-shell maintainers/scripts/update.nix --argstr path gnome`. Read the package’s `NEWS` file to see what changed.
+
+## Frequently encountered issues {#ssec-gnome-common-issues}
+
+#### `GLib-GIO-ERROR **: 06:04:50.903: No GSettings schemas are installed on the system` {#ssec-gnome-common-issues-no-schemas}
+
+There are no schemas available in `XDG_DATA_DIRS`. Temporarily add a random package containing schemas like `gsettings-desktop-schemas` to `buildInputs`. [`glib`](#ssec-gnome-hooks-glib) and [`wrapGAppsHook`](#ssec-gnome-hooks-wrapgappshook) setup hooks will take care of making the schemas available to application and you will see the actual missing schemas with the [next error](#ssec-gnome-common-issues-missing-schema). Or you can try looking through the source code for the actual schemas used.
+
+#### `GLib-GIO-ERROR **: 06:04:50.903: Settings schema ‘org.gnome.foo’ is not installed` {#ssec-gnome-common-issues-missing-schema}
+
+Package is missing some GSettings schemas. You can find out the package containing the schema with `nix-locate org.gnome.foo.gschema.xml` and let the hooks handle the wrapping as [above](#ssec-gnome-common-issues-no-schemas).
+
+#### When using `wrapGAppsHook` with special derivers you can end up with double wrapped binaries. {#ssec-gnome-common-issues-double-wrapped}
+
+This is because derivers like `python.pkgs.buildPythonApplication` or `qt5.mkDerivation` have setup-hooks automatically added that produce wrappers with makeWrapper. The simplest way to workaround that is to disable the `wrapGAppsHook` automatic wrapping with `dontWrapGApps = true;` and pass the arguments it intended to pass to makeWrapper to another.
+
+In the case of a Python application it could look like:
+
+```nix
+python3.pkgs.buildPythonApplication {
+  pname = "gnome-music";
+  version = "3.32.2";
+
+  nativeBuildInputs = [
+    wrapGAppsHook
+    gobject-introspection
+    ...
+  ];
+
+  dontWrapGApps = true;
+
+  # Arguments to be passed to `makeWrapper`, only used by buildPython*
+  preFixup = ''
+    makeWrapperArgs+=("''${gappsWrapperArgs[@]}")
+  '';
+}
+```
+
+And for a QT app like:
+
+```nix
+mkDerivation {
+  pname = "calibre";
+  version = "3.47.0";
+
+  nativeBuildInputs = [
+    wrapGAppsHook
+    qmake
+    ...
+  ];
+
+  dontWrapGApps = true;
+
+  # Arguments to be passed to `makeWrapper`, only used by qt5’s mkDerivation
+  preFixup = ''
+    qtWrapperArgs+=("''${gappsWrapperArgs[@]}")
+  '';
+}
+```
+
+#### I am packaging a project that cannot be wrapped, like a library or GNOME Shell extension. {#ssec-gnome-common-issues-unwrappable-package}
+
+You can rely on applications depending on the library setting the necessary environment variables but that is often easy to miss. Instead we recommend to patch the paths in the source code whenever possible. Here are some examples:
+
+- []{#ssec-gnome-common-issues-unwrappable-package-gnome-shell-ext} [Replacing a `GI_TYPELIB_PATH` in GNOME Shell extension](https://github.com/NixOS/nixpkgs/blob/7bb8f05f12ca3cff9da72b56caa2f7472d5732bc/pkgs/desktops/gnome-3/core/gnome-shell-extensions/default.nix#L21-L24) – we are using `substituteAll` to include the path to a typelib into a patch.
+
+- []{#ssec-gnome-common-issues-unwrappable-package-gsettings} The following examples are hardcoding GSettings schema paths. To get the schema paths we use the functions
+
+  * `glib.getSchemaPath` Takes a nix package attribute as an argument.
+
+  * `glib.makeSchemaPath` Takes a package output like `$out` and a derivation name. You should use this if the schemas you need to hardcode are in the same derivation.
+
+  []{#ssec-gnome-common-issues-unwrappable-package-gsettings-vala} [Hard-coding GSettings schema path in Vala plug-in (dynamically loaded library)](https://github.com/NixOS/nixpkgs/blob/7bb8f05f12ca3cff9da72b56caa2f7472d5732bc/pkgs/desktops/pantheon/apps/elementary-files/default.nix#L78-L86) – here, `substituteAll` cannot be used since the schema comes from the same package preventing us from pass its path to the function, probably due to a [Nix bug](https://github.com/NixOS/nix/issues/1846).
+
+  []{#ssec-gnome-common-issues-unwrappable-package-gsettings-c} [Hard-coding GSettings schema path in C library](https://github.com/NixOS/nixpkgs/blob/29c120c065d03b000224872251bed93932d42412/pkgs/development/libraries/glib-networking/default.nix#L31-L34) – nothing special other than using [Coccinelle patch](https://github.com/NixOS/nixpkgs/pull/67957#issuecomment-527717467) to generate the patch itself.
+
+#### I need to wrap a binary outside `bin` and `libexec` directories. {#ssec-gnome-common-issues-weird-location}
+
+You can manually trigger the wrapping with `wrapGApp` in `preFixup` phase. It takes a path to a program as a first argument; the remaining arguments are passed directly to [`wrapProgram`](#fun-wrapProgram) function.

doc/languages-frameworks/go.section.md

@@ -0,0 +1,149 @@
+# Go {#sec-language-go}
+
+## Go modules {#ssec-language-go}
+
+The function `buildGoModule` builds Go programs managed with Go modules. It builds a [Go Modules](https://github.com/golang/go/wiki/Modules) through a two phase build:
+
+- An intermediate fetcher derivation. This derivation will be used to fetch all of the dependencies of the Go module.
+- A final derivation will use the output of the intermediate derivation to build the binaries and produce the final output.
+
+### Example for `buildGoModule` {#ex-buildGoModule}
+
+In the following is an example expression using `buildGoModule`, the following arguments are of special significance to the function:
+
+- `vendorSha256`: is the hash of the output of the intermediate fetcher derivation. `vendorSha256` can also take `null` as an input. When `null` is used as a value, rather than fetching the dependencies and vendoring them, we use the vendoring included within the source repo. If you'd like to not have to update this field on dependency changes, run `go mod vendor` in your source repo and set `vendorSha256 = null;`
+- `proxyVendor`: Fetches (go mod download) and proxies the vendor directory. This is useful if your code depends on c code and go mod tidy does not include the needed sources to build or if any dependency has case-insensitive conflicts which will produce platform dependant `vendorSha256` checksums.
+
+```nix
+pet = buildGoModule rec {
+  pname = "pet";
+  version = "0.3.4";
+
+  src = fetchFromGitHub {
+    owner = "knqyf263";
+    repo = "pet";
+    rev = "v${version}";
+    sha256 = "0m2fzpqxk7hrbxsgqplkg7h2p7gv6s1miymv3gvw0cz039skag0s";
+  };
+
+  vendorSha256 = "1879j77k96684wi554rkjxydrj8g3hpp0kvxz03sd8dmwr3lh83j";
+
+  meta = with lib; {
+    description = "Simple command-line snippet manager, written in Go";
+    homepage = "https://github.com/knqyf263/pet";
+    license = licenses.mit;
+    maintainers = with maintainers; [ kalbasit ];
+  };
+}
+```
+
+## `buildGoPackage` (legacy) {#ssec-go-legacy}
+
+The function `buildGoPackage` builds legacy Go programs, not supporting Go modules.
+
+### Example for `buildGoPackage` {#example-for-buildgopackage}
+
+In the following is an example expression using buildGoPackage, the following arguments are of special significance to the function:
+
+- `goPackagePath` specifies the package's canonical Go import path.
+- `goDeps` is where the Go dependencies of a Go program are listed as a list of package source identified by Go import path. It could be imported as a separate `deps.nix` file for readability. The dependency data structure is described below.
+
+```nix
+deis = buildGoPackage rec {
+  pname = "deis";
+  version = "1.13.0";
+
+  goPackagePath = "github.com/deis/deis";
+
+  src = fetchFromGitHub {
+    owner = "deis";
+    repo = "deis";
+    rev = "v${version}";
+    sha256 = "1qv9lxqx7m18029lj8cw3k7jngvxs4iciwrypdy0gd2nnghc68sw";
+  };
+
+  goDeps = ./deps.nix;
+}
+```
+
+The `goDeps` attribute can be imported from a separate `nix` file that defines which Go libraries are needed and should be included in `GOPATH` for `buildPhase`:
+
+```nix
+# deps.nix
+[ # goDeps is a list of Go dependencies.
+  {
+    # goPackagePath specifies Go package import path.
+    goPackagePath = "gopkg.in/yaml.v2";
+    fetch = {
+      # `fetch type` that needs to be used to get package source.
+      # If `git` is used there should be `url`, `rev` and `sha256` defined next to it.
+      type = "git";
+      url = "https://gopkg.in/yaml.v2";
+      rev = "a83829b6f1293c91addabc89d0571c246397bbf4";
+      sha256 = "1m4dsmk90sbi17571h6pld44zxz7jc4lrnl4f27dpd1l8g5xvjhh";
+    };
+  }
+  {
+    goPackagePath = "github.com/docopt/docopt-go";
+    fetch = {
+      type = "git";
+      url = "https://github.com/docopt/docopt-go";
+      rev = "784ddc588536785e7299f7272f39101f7faccc3f";
+      sha256 = "0wwz48jl9fvl1iknvn9dqr4gfy1qs03gxaikrxxp9gry6773v3sj";
+    };
+  }
+]
+```
+
+To extract dependency information from a Go package in automated way use [go2nix](https://github.com/kamilchm/go2nix). It can produce complete derivation and `goDeps` file for Go programs.
+
+You may use Go packages installed into the active Nix profiles by adding the following to your ~/.bashrc:
+
+```bash
+for p in $NIX_PROFILES; do
+    GOPATH="$p/share/go:$GOPATH"
+done
+```
+
+## Attributes used by the builders {#ssec-go-common-attributes}
+
+Both `buildGoModule` and `buildGoPackage` can be tweaked to behave slightly differently, if the following attributes are used:
+
+### `ldflags` {#var-go-ldflags}
+
+Arguments to pass to the Go linker tool via the `-ldflags` argument of `go build`. The most common use case for this argument is to make the resulting executable aware of its own version. For example:
+
+```nix
+  ldflags = [
+    "-s" "-w"
+    "-X main.Version=${version}"
+    "-X main.Commit=${version}"
+  ];
+```
+
+### `tags` {#var-go-tags}
+
+Arguments to pass to the Go via the `-tags` argument of `go build`. For example:
+
+```nix
+  tags = [
+    "production"
+    "sqlite"
+  ];
+```
+
+```nix
+  tags = [ "production" ] ++ lib.optionals withSqlite [ "sqlite" ];
+```
+
+### `deleteVendor` {#var-go-deleteVendor}
+
+Removes the pre-existing vendor directory. This should only be used if the dependencies included in the vendor folder are broken or incomplete.
+
+### `subPackages` {#var-go-subPackages}
+
+Specified as a string or list of strings. Limits the builder from building child packages that have not been listed. If `subPackages` is not specified, all child packages will be built.
+
+### `excludedPackages` {#var-go-excludedPackages}
+
+Specified as a string or list of strings. Causes the builder to skip building child packages that match any of the provided values. If `excludedPackages` is not specified, all child packages will be built.

doc/languages-frameworks/haskell.section.md

@@ -0,0 +1,7 @@
+# Haskell {#haskell}
+
+The documentation for the Haskell infrastructure is published at
+<https://haskell4nix.readthedocs.io/>. The source code for that
+site lives in the `doc/` sub-directory of the
+[`cabal2nix` Git repository](https://github.com/NixOS/cabal2nix)
+and changes can be submitted there.

doc/languages-frameworks/hy.section.md

@@ -0,0 +1,31 @@
+# Hy {#sec-language-hy}
+
+## Installation {#ssec-hy-installation}
+
+### Installation without packages {#installation-without-packages}
+
+You can install `hy` via nix-env or by adding it to `configuration.nix` by reffering to it as a `hy` attribute. This kind of installation adds `hy` to your environment and it succesfully works with `python3`.
+
+::: {.caution}
+Packages that are installed with your python derivation, are not accesible by `hy` this way.
+:::
+
+### Installation with packages {#installation-with-packages}
+
+Creating `hy` derivation with custom `python` packages is really simple and similar to the way that python does it. Attribute `hy` provides function `withPackages` that creates custom `hy` derivation with specified packages.
+
+For example if you want to create shell with `matplotlib` and `numpy`, you can do it like so:
+
+```ShellSession
+$ nix-shell -p "hy.withPackages (ps: with ps; [ numpy matplotlib ])"
+```
+
+Or if you want to extend your `configuration.nix`:
+```nix
+{ # ...
+
+  environment.systemPackages = with pkgs; [
+    (hy.withPackages (py-packages: with py-packages; [ numpy matplotlib ]))
+  ];
+}
+```

doc/languages-frameworks/idris.section.md

@@ -0,0 +1,143 @@
+# Idris {#idris}
+
+## Installing Idris {#installing-idris}
+
+The easiest way to get a working idris version is to install the `idris` attribute:
+
+```ShellSession
+$ nix-env -f "<nixpkgs>" -iA idris
+```
+
+This however only provides the `prelude` and `base` libraries. To install idris with additional libraries, you can use the `idrisPackages.with-packages` function, e.g. in an overlay in `~/.config/nixpkgs/overlays/my-idris.nix`:
+
+```nix
+self: super: {
+  myIdris = with self.idrisPackages; with-packages [ contrib pruviloj ];
+}
+```
+
+And then:
+
+```ShellSession
+$ # On NixOS
+$ nix-env -iA nixos.myIdris
+$ # On non-NixOS
+$ nix-env -iA nixpkgs.myIdris
+```
+
+To see all available Idris packages:
+
+```ShellSession
+$ # On NixOS
+$ nix-env -qaPA nixos.idrisPackages
+$ # On non-NixOS
+$ nix-env -qaPA nixpkgs.idrisPackages
+```
+
+Similarly, entering a `nix-shell`:
+
+```ShellSession
+$ nix-shell -p 'idrisPackages.with-packages (with idrisPackages; [ contrib pruviloj ])'
+```
+
+## Starting Idris with library support {#starting-idris-with-library-support}
+
+To have access to these libraries in idris, call it with an argument `-p <library name>` for each library:
+
+```ShellSession
+$ nix-shell -p 'idrisPackages.with-packages (with idrisPackages; [ contrib pruviloj ])'
+[nix-shell:~]$ idris -p contrib -p pruviloj
+```
+
+A listing of all available packages the Idris binary has access to is available via `--listlibs`:
+
+```ShellSession
+$ idris --listlibs
+00prelude-idx.ibc
+pruviloj
+base
+contrib
+prelude
+00pruviloj-idx.ibc
+00base-idx.ibc
+00contrib-idx.ibc
+```
+
+## Building an Idris project with Nix {#building-an-idris-project-with-nix}
+
+As an example of how a Nix expression for an Idris package can be created, here is the one for `idrisPackages.yaml`:
+
+```nix
+{ lib
+, build-idris-package
+, fetchFromGitHub
+, contrib
+, lightyear
+}:
+build-idris-package  {
+  name = "yaml";
+  version = "2018-01-25";
+
+  # This is the .ipkg file that should be built, defaults to the package name
+  # In this case it should build `Yaml.ipkg` instead of `yaml.ipkg`
+  # This is only necessary because the yaml packages ipkg file is
+  # different from its package name here.
+  ipkgName = "Yaml";
+  # Idris dependencies to provide for the build
+  idrisDeps = [ contrib lightyear ];
+
+  src = fetchFromGitHub {
+    owner = "Heather";
+    repo = "Idris.Yaml";
+    rev = "5afa51ffc839844862b8316faba3bafa15656db4";
+    sha256 = "1g4pi0swmg214kndj85hj50ccmckni7piprsxfdzdfhg87s0avw7";
+  };
+
+  meta = with lib; {
+    description = "Idris YAML lib";
+    homepage = "https://github.com/Heather/Idris.Yaml";
+    license = licenses.mit;
+    maintainers = [ maintainers.brainrape ];
+  };
+}
+```
+
+Assuming this file is saved as `yaml.nix`, it's buildable using
+
+```ShellSession
+$ nix-build -E '(import <nixpkgs> {}).idrisPackages.callPackage ./yaml.nix {}'
+```
+
+Or it's possible to use
+
+```nix
+with import <nixpkgs> {};
+
+{
+  yaml = idrisPackages.callPackage ./yaml.nix {};
+}
+```
+
+in another file (say `default.nix`) to be able to build it with
+
+```ShellSession
+$ nix-build -A yaml
+```
+
+## Passing options to `idris` commands {#passing-options-to-idris-commands}
+
+The `build-idris-package` function provides also optional input values to set additional options for the used `idris` commands.
+
+Specifically, you can set `idrisBuildOptions`, `idrisTestOptions`, `idrisInstallOptions` and `idrisDocOptions` to provide additional options to the `idris` command respectively when building, testing, installing and generating docs for your package.
+
+For example you could set
+
+```nix
+build-idris-package {
+  idrisBuildOptions = [ "--log" "1" "--verbose" ]
+
+  ...
+}
+```
+
+to require verbose output during `idris` build phase.

doc/languages-frameworks/index.xml

@@ -0,0 +1,42 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         xml:id="chap-language-support">
+ <title>Languages and frameworks</title>
+ <para>
+  The <link linkend="chap-stdenv">standard build environment</link> makes it easy to build typical Autotools-based packages with very little code. Any other kind of package can be accomodated by overriding the appropriate phases of <literal>stdenv</literal>. However, there are specialised functions in Nixpkgs to easily build packages for other programming languages, such as Perl or Haskell. These are described in this chapter.
+ </para>
+ <xi:include href="agda.section.xml" />
+ <xi:include href="android.section.xml" />
+ <xi:include href="beam.section.xml" />
+ <xi:include href="bower.section.xml" />
+ <xi:include href="chicken.section.xml" />
+ <xi:include href="coq.section.xml" />
+ <xi:include href="crystal.section.xml" />
+ <xi:include href="cuda.section.xml" />
+ <xi:include href="dhall.section.xml" />
+ <xi:include href="dotnet.section.xml" />
+ <xi:include href="emscripten.section.xml" />
+ <xi:include href="gnome.section.xml" />
+ <xi:include href="go.section.xml" />
+ <xi:include href="haskell.section.xml" />
+ <xi:include href="hy.section.xml" />
+ <xi:include href="idris.section.xml" />
+ <xi:include href="ios.section.xml" />
+ <xi:include href="java.section.xml" />
+ <xi:include href="javascript.section.xml" />
+ <xi:include href="lua.section.xml" />
+ <xi:include href="maven.section.xml" />
+ <xi:include href="nim.section.xml" />
+ <xi:include href="ocaml.section.xml" />
+ <xi:include href="octave.section.xml" />
+ <xi:include href="perl.section.xml" />
+ <xi:include href="php.section.xml" />
+ <xi:include href="python.section.xml" />
+ <xi:include href="qt.section.xml" />
+ <xi:include href="r.section.xml" />
+ <xi:include href="ruby.section.xml" />
+ <xi:include href="rust.section.xml" />
+ <xi:include href="texlive.section.xml" />
+ <xi:include href="titanium.section.xml" />
+ <xi:include href="vim.section.xml" />
+</chapter>

doc/languages-frameworks/ios.section.md

@@ -0,0 +1,225 @@
+# iOS {#ios}
+
+This component is basically a wrapper/workaround that makes it possible to
+expose an Xcode installation as a Nix package by means of symlinking to the
+relevant executables on the host system.
+
+Since Xcode can't be packaged with Nix, nor we can publish it as a Nix package
+(because of its license) this is basically the only integration strategy
+making it possible to do iOS application builds that integrate with other
+components of the Nix ecosystem
+
+The primary objective of this project is to use the Nix expression language to
+specify how iOS apps can be built from source code, and to automatically spawn
+iOS simulator instances for testing.
+
+This component also makes it possible to use [Hydra](https://nixos.org/hydra),
+the Nix-based continuous integration server to regularly build iOS apps and to
+do wireless ad-hoc installations of enterprise IPAs on iOS devices through
+Hydra.
+
+The Xcode build environment implements a number of features.
+
+## Deploying a proxy component wrapper exposing Xcode {#deploying-a-proxy-component-wrapper-exposing-xcode}
+
+The first use case is deploying a Nix package that provides symlinks to the Xcode
+installation on the host system. This package can be used as a build input to
+any build function implemented in the Nix expression language that requires
+Xcode.
+
+```nix
+let
+  pkgs = import <nixpkgs> {};
+
+  xcodeenv = import ./xcodeenv {
+    inherit (pkgs) stdenv;
+  };
+in
+xcodeenv.composeXcodeWrapper {
+  version = "9.2";
+  xcodeBaseDir = "/Applications/Xcode.app";
+}
+```
+
+By deploying the above expression with `nix-build` and inspecting its content
+you will notice that several Xcode-related executables are exposed as a Nix
+package:
+
+```bash
+$ ls result/bin
+lrwxr-xr-x  1 sander  staff  94  1 jan  1970 Simulator -> /Applications/Xcode.app/Contents/Developer/Applications/Simulator.app/Contents/MacOS/Simulator
+lrwxr-xr-x  1 sander  staff  17  1 jan  1970 codesign -> /usr/bin/codesign
+lrwxr-xr-x  1 sander  staff  17  1 jan  1970 security -> /usr/bin/security
+lrwxr-xr-x  1 sander  staff  21  1 jan  1970 xcode-select -> /usr/bin/xcode-select
+lrwxr-xr-x  1 sander  staff  61  1 jan  1970 xcodebuild -> /Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild
+lrwxr-xr-x  1 sander  staff  14  1 jan  1970 xcrun -> /usr/bin/xcrun
+```
+
+## Building an iOS application {#building-an-ios-application}
+
+We can build an iOS app executable for the simulator, or an IPA/xcarchive file
+for release purposes, e.g. ad-hoc, enterprise or store installations, by
+executing the `xcodeenv.buildApp {}` function:
+
+```nix
+let
+  pkgs = import <nixpkgs> {};
+
+  xcodeenv = import ./xcodeenv {
+    inherit (pkgs) stdenv;
+  };
+in
+xcodeenv.buildApp {
+  name = "MyApp";
+  src = ./myappsources;
+  sdkVersion = "11.2";
+
+  target = null; # Corresponds to the name of the app by default
+  configuration = null; # Release for release builds, Debug for debug builds
+  scheme = null; # -scheme will correspond to the app name by default
+  sdk = null; # null will set it to 'iphonesimulator` for simulator builds or `iphoneos` to real builds
+  xcodeFlags = "";
+
+  release = true;
+  certificateFile = ./mycertificate.p12;
+  certificatePassword = "secret";
+  provisioningProfile = ./myprovisioning.profile;
+  signMethod = "ad-hoc"; # 'enterprise' or 'store'
+  generateIPA = true;
+  generateXCArchive = false;
+
+  enableWirelessDistribution = true;
+  installURL = "/installipa.php";
+  bundleId = "mycompany.myapp";
+  appVersion = "1.0";
+
+  # Supports all xcodewrapper parameters as well
+  xcodeBaseDir = "/Applications/Xcode.app";
+}
+```
+
+The above function takes a variety of parameters:
+
+* The `name` and `src` parameters are mandatory and specify the name of the app
+  and the location where the source code resides
+* `sdkVersion` specifies which version of the iOS SDK to use.
+
+It also possile to adjust the `xcodebuild` parameters. This is only needed in
+rare circumstances. In most cases the default values should suffice:
+
+* Specifies which `xcodebuild` target to build. By default it takes the target
+  that has the same name as the app.
+* The `configuration` parameter can be overridden if desired. By default, it
+  will do a debug build for the simulator and a release build for real devices.
+* The `scheme` parameter specifies which `-scheme` parameter to propagate to
+  `xcodebuild`. By default, it corresponds to the app name.
+* The `sdk` parameter specifies which SDK to use. By default, it picks
+  `iphonesimulator` for simulator builds and `iphoneos` for release builds.
+* The `xcodeFlags` parameter specifies arbitrary command line parameters that
+  should be propagated to `xcodebuild`.
+
+By default, builds are carried out for the iOS simulator. To do release builds
+(builds for real iOS devices), you must set the `release` parameter to `true`.
+In addition, you need to set the following parameters:
+
+* `certificateFile` refers to a P12 certificate file.
+* `certificatePassword` specifies the password of the P12 certificate.
+* `provisioningProfile` refers to the provision profile needed to sign the app
+* `signMethod` should refer to `ad-hoc` for signing the app with an ad-hoc
+  certificate, `enterprise` for enterprise certificates and `app-store` for App
+  store certificates.
+* `generateIPA` specifies that we want to produce an IPA file (this is probably
+  what you want)
+* `generateXCArchive` specifies thet we want to produce an xcarchive file.
+
+When building IPA files on Hydra and when it is desired to allow iOS devices to
+install IPAs by browsing to the Hydra build products page, you can enable the
+`enableWirelessDistribution` parameter.
+
+When enabled, you need to configure the following options:
+
+* The `installURL` parameter refers to the URL of a PHP script that composes the
+  `itms-services://` URL allowing iOS devices to install the IPA file.
+* `bundleId` refers to the bundle ID value of the app
+* `appVersion` refers to the app's version number
+
+To use wireless adhoc distributions, you must also install the corresponding
+PHP script on a web server (see section: 'Installing the PHP script for wireless
+ad hoc installations from Hydra' for more information).
+
+In addition to the build parameters, you can also specify any parameters that
+the `xcodeenv.composeXcodeWrapper {}` function takes. For example, the
+`xcodeBaseDir` parameter can be overridden to refer to a different Xcode
+version.
+
+## Spawning simulator instances {#spawning-simulator-instances}
+
+In addition to building iOS apps, we can also automatically spawn simulator
+instances:
+
+```nix
+let
+  pkgs = import <nixpkgs> {};
+
+  xcodeenv = import ./xcodeenv {
+    inherit (pkgs) stdenv;
+  };
+in
+xcode.simulateApp {
+  name = "simulate";
+
+  # Supports all xcodewrapper parameters as well
+  xcodeBaseDir = "/Applications/Xcode.app";
+}
+```
+
+The above expression produces a script that starts the simulator from the
+provided Xcode installation. The script can be started as follows:
+
+```bash
+./result/bin/run-test-simulator
+```
+
+By default, the script will show an overview of UDID for all available simulator
+instances and asks you to pick one. You can also provide a UDID as a
+command-line parameter to launch an instance automatically:
+
+```bash
+./result/bin/run-test-simulator 5C93129D-CF39-4B1A-955F-15180C3BD4B8
+```
+
+You can also extend the simulator script to automatically deploy and launch an
+app in the requested simulator instance:
+
+```nix
+let
+  pkgs = import <nixpkgs> {};
+
+  xcodeenv = import ./xcodeenv {
+    inherit (pkgs) stdenv;
+  };
+in
+xcode.simulateApp {
+  name = "simulate";
+  bundleId = "mycompany.myapp";
+  app = xcode.buildApp {
+    # ...
+  };
+
+  # Supports all xcodewrapper parameters as well
+  xcodeBaseDir = "/Applications/Xcode.app";
+}
+```
+
+By providing the result of an `xcode.buildApp {}` function and configuring the
+app bundle id, the app gets deployed automatically and started.
+
+## Troubleshooting {#troubleshooting}
+
+In some rare cases, it may happen that after a failure, changes are not picked
+up. Most likely, this is caused by a derived data cache that Xcode maintains.
+To wipe it you can run:
+
+```bash
+$ rm -rf ~/Library/Developer/Xcode/DerivedData
+```

doc/languages-frameworks/java.section.md

@@ -0,0 +1,100 @@
+# Java {#sec-language-java}
+
+Ant-based Java packages are typically built from source as follows:
+
+```nix
+stdenv.mkDerivation {
+  name = "...";
+  src = fetchurl { ... };
+
+  nativeBuildInputs = [ jdk ant ];
+
+  buildPhase = "ant";
+}
+```
+
+Note that `jdk` is an alias for the OpenJDK (self-built where available,
+or pre-built via Zulu). Platforms with OpenJDK not (yet) in Nixpkgs
+(`Aarch32`, `Aarch64`) point to the (unfree) `oraclejdk`.
+
+JAR files that are intended to be used by other packages should be
+installed in `$out/share/java`. JDKs have a stdenv setup hook that add
+any JARs in the `share/java` directories of the build inputs to the
+`CLASSPATH` environment variable. For instance, if the package `libfoo`
+installs a JAR named `foo.jar` in its `share/java` directory, and
+another package declares the attribute
+
+```nix
+buildInputs = [ libfoo ];
+nativeBuildInputs = [ jdk ];
+```
+
+then `CLASSPATH` will be set to
+`/nix/store/...-libfoo/share/java/foo.jar`.
+
+Private JARs should be installed in a location like
+`$out/share/package-name`.
+
+If your Java package provides a program, you need to generate a wrapper
+script to run it using a JRE. You can use `makeWrapper` for this:
+
+```nix
+nativeBuildInputs = [ makeWrapper ];
+
+installPhase = ''
+  mkdir -p $out/bin
+  makeWrapper ${jre}/bin/java $out/bin/foo \
+    --add-flags "-cp $out/share/java/foo.jar org.foo.Main"
+'';
+```
+
+Since the introduction of the Java Platform Module System in Java 9,
+Java distributions typically no longer ship with a general-purpose JRE:
+instead, they allow generating a JRE with only the modules required for
+your application(s). Because we can't predict what modules will be
+needed on a general-purpose system, the default jre package is the full
+JDK. When building a minimal system/image, you can override the
+`modules` parameter on `jre_minimal` to build a JRE with only the
+modules relevant for you:
+
+```nix
+let
+  my_jre = pkgs.jre_minimal.override {
+    modules = [
+      # The modules used by 'something' and 'other' combined:
+      "java.base"
+      "java.logging"
+    ];
+  };
+  something = (pkgs.something.override { jre = my_jre; });
+  other = (pkgs.other.override { jre = my_jre; });
+in
+  ...
+```
+
+You can also specify what JDK your JRE should be based on, for example
+selecting a 'headless' build to avoid including a link to GTK+:
+
+```nix
+my_jre = pkgs.jre_minimal.override {
+  jdk = jdk11_headless;
+};
+```
+
+Note all JDKs passthru `home`, so if your application requires
+environment variables like `JAVA_HOME` being set, that can be done in a
+generic fashion with the `--set` argument of `makeWrapper`:
+
+```bash
+--set JAVA_HOME ${jdk.home}
+```
+
+It is possible to use a different Java compiler than `javac` from the
+OpenJDK. For instance, to use the GNU Java Compiler:
+
+```nix
+nativeBuildInputs = [ gcj ant ];
+```
+
+Here, Ant will automatically use `gij` (the GNU Java Runtime) instead of
+the OpenJRE.

doc/languages-frameworks/javascript.section.md

@@ -0,0 +1,275 @@
+# Javascript {#language-javascript}
+
+## Introduction {#javascript-introduction}
+
+This contains instructions on how to package javascript applications.
+
+The various tools available will be listed in the [tools-overview](#javascript-tools-overview). Some general principles for packaging will follow. Finally some tool specific instructions will be given.
+
+## Getting unstuck / finding code examples
+
+If you find you are lacking inspiration for packing javascript applications, the links below might prove useful. Searching online for prior art can be helpful if you are running into solved problems.
+
+### Github
+
+- Searching Nix files for `mkYarnPackage`: <https://github.com/search?q=mkYarnPackage+language%3ANix&type=code>
+- Searching just `flake.nix` files for `mkYarnPackage`: <https://github.com/search?q=mkYarnPackage+filename%3Aflake.nix&type=code>
+
+### Gitlab
+
+- Searching Nix files for `mkYarnPackage`: <https://gitlab.com/search?scope=blobs&search=mkYarnPackage+extension%3Anix>
+- Searching just `flake.nix` files for `mkYarnPackage`: <https://gitlab.com/search?scope=blobs&search=mkYarnPackage+filename%3Aflake.nix>
+
+## Tools overview {#javascript-tools-overview}
+
+## General principles {#javascript-general-principles}
+
+The following principles are given in order of importance with potential exceptions.
+
+### Try to use the same node version used upstream {#javascript-upstream-node-version}
+
+It is often not documented which node version is used upstream, but if it is, try to use the same version when packaging.
+
+This can be a problem if upstream is using the latest and greatest and you are trying to use an earlier version of node. Some cryptic errors regarding V8 may appear.
+
+### Try to respect the package manager originally used by upstream (and use the upstream lock file) {#javascript-upstream-package-manager}
+
+A lock file (package-lock.json, yarn.lock...) is supposed to make reproducible installations of node_modules for each tool.
+
+Guidelines of package managers, recommend to commit those lock files to the repos. If a particular lock file is present, it is a strong indication of which package manager is used upstream.
+
+It's better to try to use a Nix tool that understand the lock file. Using a different tool might give you hard to understand error because different packages have been installed. An example of problems that could arise can be found [here](https://github.com/NixOS/nixpkgs/pull/126629). Upstream use NPM, but this is an attempt to package it with `yarn2nix` (that uses yarn.lock).
+
+Using a different tool forces to commit a lock file to the repository. Those files are fairly large, so when packaging for nixpkgs, this approach does not scale well.
+
+Exceptions to this rule are:
+
+- When you encounter one of the bugs from a Nix tool. In each of the tool specific instructions, known problems will be detailed. If you have a problem with a particular tool, then it's best to try another tool, even if this means you will have to recreate a lock file and commit it to nixpkgs. In general `yarn2nix` has less known problems and so a simple search in nixpkgs will reveal many yarn.lock files committed.
+- Some lock files contain particular version of a package that has been pulled off NPM for some reason. In that case, you can recreate upstream lock (by removing the original and `npm install`, `yarn`, ...) and commit this to nixpkgs.
+- The only tool that supports workspaces (a feature of NPM that helps manage sub-directories with different package.json from a single top level package.json) is `yarn2nix`. If upstream has workspaces you should try `yarn2nix`.
+
+### Try to use upstream package.json {#javascript-upstream-package-json}
+
+Exceptions to this rule are:
+
+- Sometimes the upstream repo assumes some dependencies be installed globally. In that case you can add them manually to the upstream package.json (`yarn add xxx` or `npm install xxx`, ...). Dependencies that are installed locally can be executed with `npx` for CLI tools. (e.g. `npx postcss ...`, this is how you can call those dependencies in the phases).
+- Sometimes there is a version conflict between some dependency requirements. In that case you can fix a version by removing the `^`.
+- Sometimes the script defined in the package.json does not work as is. Some scripts for example use CLI tools that might not be available, or cd in directory with a different package.json (for workspaces notably). In that case, it's perfectly fine to look at what the particular script is doing and break this down in the phases. In the build script you can see `build:*` calling in turns several other build scripts like `build:ui` or `build:server`. If one of those fails, you can try to separate those into,
+
+  ```sh
+  yarn build:ui
+  yarn build:server
+  # OR
+  npm run build:ui
+  npm run build:server
+  ```
+
+  when you need to override a package.json. It's nice to use the one from the upstream source and do some explicit override. Here is an example:
+
+  ```nix
+  patchedPackageJSON = final.runCommand "package.json" { } ''
+    ${jq}/bin/jq '.version = "0.4.0" |
+      .devDependencies."@jsdoc/cli" = "^0.2.5"
+      ${sonar-src}/package.json > $out
+  '';
+  ```
+
+  You will still need to commit the modified version of the lock files, but at least the overrides are explicit for everyone to see.
+
+### Using node_modules directly {#javascript-using-node_modules}
+
+Each tool has an abstraction to just build the node_modules (dependencies) directory. You can always use the `stdenv.mkDerivation` with the node_modules to build the package (symlink the node_modules directory and then use the package build command). The node_modules abstraction can be also used to build some web framework frontends. For an example of this see how [plausible](https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/web-apps/plausible/default.nix) is built. `mkYarnModules` to make the derivation containing node_modules. Then when building the frontend you can just symlink the node_modules directory.
+
+## Javascript packages inside nixpkgs {#javascript-packages-nixpkgs}
+
+The [pkgs/development/node-packages](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/node-packages) folder contains a generated collection of [NPM packages](https://npmjs.com/) that can be installed with the Nix package manager.
+
+As a rule of thumb, the package set should only provide _end user_ software packages, such as command-line utilities. Libraries should only be added to the package set if there is a non-NPM package that requires it.
+
+When it is desired to use NPM libraries in a development project, use the `node2nix` generator directly on the `package.json` configuration file of the project.
+
+The package set provides support for the official stable Node.js versions. The latest stable LTS release in `nodePackages`, as well as the latest stable current release in `nodePackages_latest`.
+
+If your package uses native addons, you need to examine what kind of native build system it uses. Here are some examples:
+
+- `node-gyp`
+- `node-gyp-builder`
+- `node-pre-gyp`
+
+After you have identified the correct system, you need to override your package expression while adding in build system as a build input. For example, `dat` requires `node-gyp-build`, so we override its expression in [pkgs/development/node-packages/overrides.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/node-packages/overrides.nix):
+
+```nix
+    dat = prev.dat.override (oldAttrs: {
+      buildInputs = [ final.node-gyp-build pkgs.libtool pkgs.autoconf pkgs.automake ];
+      meta = oldAttrs.meta // { broken = since "12"; };
+    });
+```
+
+### Adding and Updating Javascript packages in nixpkgs
+
+To add a package from NPM to nixpkgs:
+
+1. Modify [pkgs/development/node-packages/node-packages.json](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/node-packages/node-packages.json) to add, update or remove package entries to have it included in `nodePackages` and `nodePackages_latest`.
+2. Run the script:
+
+   ```sh
+   ./pkgs/development/node-packages/generate.sh
+   ```
+
+3. Build your new package to test your changes:
+
+   ```sh
+   nix-build -A nodePackages.<new-or-updated-package>
+   ```
+
+    To build against the latest stable Current Node.js version (e.g. 18.x):
+
+    ```sh
+    nix-build -A nodePackages_latest.<new-or-updated-package>
+    ```
+
+    If the package doesn't build, you may need to add an override as explained above.
+4. If the package's name doesn't match any of the executables it provides, add an entry in [pkgs/development/node-packages/main-programs.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/node-packages/main-programs.nix). This will be the case for all scoped packages, e.g., `@angular/cli`.
+5. Add and commit all modified and generated files.
+
+For more information about the generation process, consult the [README.md](https://github.com/svanderburg/node2nix) file of the `node2nix` tool.
+
+To update NPM packages in nixpkgs, run the same `generate.sh` script:
+
+```sh
+./pkgs/development/node-packages/generate.sh
+```
+
+#### Git protocol error
+
+Some packages may have Git dependencies from GitHub specified with `git://`.
+GitHub has [disabled unecrypted Git connections](https://github.blog/2021-09-01-improving-git-protocol-security-github/#no-more-unauthenticated-git), so you may see the following error when running the generate script:
+
+```
+The unauthenticated git protocol on port 9418 is no longer supported
+```
+
+Use the following Git configuration to resolve the issue:
+
+```sh
+git config --global url."https://github.com/".insteadOf git://github.com/
+```
+
+## Tool specific instructions {#javascript-tool-specific}
+
+### node2nix {#javascript-node2nix}
+
+#### Preparation {#javascript-node2nix-preparation}
+
+You will need to generate a Nix expression for the dependencies. Don't forget the `-l package-lock.json` if there is a lock file. Most probably you will need the `--development` to include the `devDependencies`
+
+So the command will most likely be:
+```sh
+node2nix --development -l package-lock.json
+```
+
+See `node2nix` [docs](https://github.com/svanderburg/node2nix) for more info.
+
+#### Pitfalls {#javascript-node2nix-pitfalls}
+
+- If upstream package.json does not have a "version" attribute, `node2nix` will crash. You will need to add it like shown in [the package.json section](#javascript-upstream-package-json).
+- `node2nix` has some [bugs](https://github.com/svanderburg/node2nix/issues/238) related to working with lock files from NPM distributed with `nodejs-16_x`.
+- `node2nix` does not like missing packages from NPM. If you see something like `Cannot resolve version: vue-loader-v16@undefined` then you might want to try another tool. The package might have been pulled off of NPM.
+
+### yarn2nix {#javascript-yarn2nix}
+
+#### Preparation {#javascript-yarn2nix-preparation}
+
+You will need at least a yarn.lock and yarn.nix file.
+
+- Generate a yarn.lock in upstream if it is not already there.
+- `yarn2nix > yarn.nix` will generate the dependencies in a Nix format.
+
+#### mkYarnPackage {#javascript-yarn2nix-mkYarnPackage}
+
+This will by default try to generate a binary. For package only generating static assets (Svelte, Vue, React...), you will need to explicitly override the build step with your instructions. It's important to use the `--offline` flag. For example if you script is `"build": "something"` in package.json use:
+
+```nix
+buildPhase = ''
+  yarn build --offline
+'';
+```
+
+The dist phase is also trying to build a binary, the only way to override it is with:
+
+```nix
+distPhase = "true";
+```
+
+The configure phase can sometimes fail because it tries to be too clever. One common override is:
+
+```nix
+configurePhase = "ln -s $node_modules node_modules";
+```
+
+#### mkYarnModules {#javascript-yarn2nix-mkYarnModules}
+
+This will generate a derivation including the node_modules. If you have to build a derivation for an integrated web framework (rails, phoenix..), this is probably the easiest way. [Plausible](https://github.com/NixOS/nixpkgs/blob/master/pkgs/servers/web-apps/plausible/default.nix#L39) offers a good example of how to do this.
+
+#### Overriding dependency behavior
+
+In the `mkYarnPackage` record the property `pkgConfig` can be used to override packages when you encounter problems building.
+
+For instance, say your package is throwing errors when trying to invoke node-sass:
+
+```
+ENOENT: no such file or directory, scandir '/build/source/node_modules/node-sass/vendor'
+```
+
+To fix this we will specify different versions of build inputs to use, as well as some post install steps to get the software built the way we want:
+
+```nix
+mkYarnPackage rec {
+  pkgConfig = {
+    node-sass = {
+      buildInputs = with final;[ python libsass pkg-config ];
+      postInstall = ''
+        LIBSASS_EXT=auto yarn --offline run build
+        rm build/config.gypi
+      '';
+    };
+  };
+}
+```
+
+#### Pitfalls {#javascript-yarn2nix-pitfalls}
+
+- If version is missing from upstream package.json, yarn will silently install nothing. In that case, you will need to override package.json as shown in the [package.json section](#javascript-upstream-package-json)
+- Having trouble with `node-gyp`? Try adding these lines to the `yarnPreBuild` steps:
+
+  ```nix
+  yarnPreBuild = ''
+    mkdir -p $HOME/.node-gyp/${nodejs.version}
+    echo 9 > $HOME/.node-gyp/${nodejs.version}/installVersion
+    ln -sfv ${nodejs}/include $HOME/.node-gyp/${nodejs.version}
+    export npm_config_nodedir=${nodejs}
+  '';
+  ```
+
+  - The `echo 9` steps comes from this answer: <https://stackoverflow.com/a/49139496>
+  - Exporting the headers in `npm_config_nodedir` comes from this issue: <https://github.com/nodejs/node-gyp/issues/1191#issuecomment-301243919>
+
+## Outside of nixpkgs {#javascript-outside-nixpkgs}
+
+There are some other options available that can't be used inside nixpkgs. Those other options are written in Nix. Importing them in nixpkgs will require moving the source code into nixpkgs. Using [Import From Derivation](https://nixos.wiki/wiki/Import_From_Derivation) is not allowed in Hydra at present. If you are packaging something outside nixpkgs, those can be considered
+
+### npmlock2nix {#javascript-npmlock2nix}
+
+[npmlock2nix](https://github.com/nix-community/npmlock2nix) aims at building node_modules without code generation. It hasn't reached v1 yet, the API might be subject to change.
+
+#### Pitfalls {#javascript-npmlock2nix-pitfalls}
+
+There are some [problems with npm v7](https://github.com/tweag/npmlock2nix/issues/45).
+
+### nix-npm-buildpackage {#javascript-nix-npm-buildpackage}
+
+[nix-npm-buildpackage](https://github.com/serokell/nix-npm-buildpackage) aims at building node_modules without code generation. It hasn't reached v1 yet, the API might change. It supports both package-lock.json and yarn.lock.
+
+#### Pitfalls {#javascript-nix-npm-buildpackage-pitfalls}
+
+There are some [problems with npm v7](https://github.com/serokell/nix-npm-buildpackage/issues/33).

doc/languages-frameworks/lua.section.md

@@ -0,0 +1,253 @@
+# User’s Guide to Lua Infrastructure {#users-guide-to-lua-infrastructure}
+
+## Using Lua {#using-lua}
+
+### Overview of Lua {#overview-of-lua}
+
+Several versions of the Lua interpreter are available: luajit, lua 5.1, 5.2, 5.3.
+The attribute `lua` refers to the default interpreter, it is also possible to refer to specific versions, e.g. `lua5_2` refers to Lua 5.2.
+
+Lua libraries are in separate sets, with one set per interpreter version.
+
+The interpreters have several common attributes. One of these attributes is
+`pkgs`, which is a package set of Lua libraries for this specific
+interpreter. E.g., the `busted` package corresponding to the default interpreter
+is `lua.pkgs.busted`, and the lua 5.2 version is `lua5_2.pkgs.busted`.
+The main package set contains aliases to these package sets, e.g.
+`luaPackages` refers to `lua5_1.pkgs` and `lua52Packages` to
+`lua5_2.pkgs`.
+
+### Installing Lua and packages {#installing-lua-and-packages}
+
+#### Lua environment defined in separate `.nix` file {#lua-environment-defined-in-separate-.nix-file}
+
+Create a file, e.g. `build.nix`, with the following expression
+
+```nix
+with import <nixpkgs> {};
+
+lua5_2.withPackages (ps: with ps; [ busted luafilesystem ])
+```
+
+and install it in your profile with
+
+```shell
+nix-env -if build.nix
+```
+Now you can use the Lua interpreter, as well as the extra packages (`busted`,
+`luafilesystem`) that you added to the environment.
+
+#### Lua environment defined in `~/.config/nixpkgs/config.nix` {#lua-environment-defined-in-.confignixpkgsconfig.nix}
+
+If you prefer to, you could also add the environment as a package override to the Nixpkgs set, e.g.
+using `config.nix`,
+
+```nix
+{ # ...
+
+  packageOverrides = pkgs: with pkgs; {
+    myLuaEnv = lua5_2.withPackages (ps: with ps; [ busted luafilesystem ]);
+  };
+}
+```
+
+and install it in your profile with
+
+```shell
+nix-env -iA nixpkgs.myLuaEnv
+```
+The environment is installed by referring to the attribute, and considering
+the `nixpkgs` channel was used.
+
+#### Lua environment defined in `/etc/nixos/configuration.nix` {#lua-environment-defined-in-etcnixosconfiguration.nix}
+
+For the sake of completeness, here's another example how to install the environment system-wide.
+
+```nix
+{ # ...
+
+  environment.systemPackages = with pkgs; [
+    (lua.withPackages(ps: with ps; [ busted luafilesystem ]))
+  ];
+}
+```
+
+### How to override a Lua package using overlays? {#how-to-override-a-lua-package-using-overlays}
+
+Use the following overlay template:
+
+```nix
+final: prev:
+{
+
+  lua = prev.lua.override {
+    packageOverrides = luaself: luaprev: {
+
+      luarocks-nix = luaprev.luarocks-nix.overrideAttrs(oa: {
+        pname = "luarocks-nix";
+        src = /home/my_luarocks/repository;
+      });
+  };
+
+  luaPackages = lua.pkgs;
+}
+```
+
+### Temporary Lua environment with `nix-shell` {#temporary-lua-environment-with-nix-shell}
+
+
+There are two methods for loading a shell with Lua packages. The first and recommended method
+is to create an environment with `lua.buildEnv` or `lua.withPackages` and load that. E.g.
+
+```sh
+$ nix-shell -p 'lua.withPackages(ps: with ps; [ busted luafilesystem ])'
+```
+
+opens a shell from which you can launch the interpreter
+
+```sh
+[nix-shell:~] lua
+```
+
+The other method, which is not recommended, does not create an environment and requires you to list the packages directly,
+
+```sh
+$ nix-shell -p lua.pkgs.busted lua.pkgs.luafilesystem
+```
+Again, it is possible to launch the interpreter from the shell.
+The Lua interpreter has the attribute `pkgs` which contains all Lua libraries for that specific interpreter.
+
+
+## Developing with Lua {#developing-with-lua}
+
+Now that you know how to get a working Lua environment with Nix, it is time
+to go forward and start actually developing with Lua. There are two ways to
+package lua software, either it is on luarocks and most of it can be taken care
+of by the luarocks2nix converter or the packaging has to be done manually.
+Let's present the luarocks way first and the manual one in a second time.
+
+### Packaging a library on luarocks {#packaging-a-library-on-luarocks}
+
+[Luarocks.org](https://luarocks.org/) is the main repository of lua packages.
+The site proposes two types of packages, the rockspec and the src.rock
+(equivalent of a [rockspec](https://github.com/luarocks/luarocks/wiki/Rockspec-format) but with the source).
+These packages can have different build types such as `cmake`, `builtin` etc .
+
+Luarocks-based packages are generated in pkgs/development/lua-modules/generated-packages.nix from
+the whitelist maintainers/scripts/luarocks-packages.csv and updated by running maintainers/scripts/update-luarocks-packages.
+
+[luarocks2nix](https://github.com/nix-community/luarocks) is a tool capable of generating nix derivations from both rockspec and src.rock (and favors the src.rock).
+The automation only goes so far though and some packages need to be customized.
+These customizations go in `pkgs/development/lua-modules/overrides.nix`.
+For instance if the rockspec defines `external_dependencies`, these need to be manually added to the overrides.nix.
+
+You can try converting luarocks packages to nix packages with the command `nix-shell -p luarocks-nix` and then `luarocks nix PKG_NAME`.
+
+#### Packaging a library manually {#packaging-a-library-manually}
+
+You can develop your package as you usually would, just don't forget to wrap it
+within a `toLuaModule` call, for instance
+
+```nix
+mynewlib = toLuaModule ( stdenv.mkDerivation { ... });
+```
+
+There is also the `buildLuaPackage` function that can be used when lua modules
+are not packaged for luarocks. You can see a few examples at `pkgs/top-level/lua-packages.nix`.
+
+## Lua Reference {#lua-reference}
+
+### Lua interpreters {#lua-interpreters}
+
+Versions 5.1, 5.2, 5.3 and 5.4 of the lua interpreter are available as
+respectively `lua5_1`, `lua5_2`, `lua5_3` and `lua5_4`. Luajit is available too.
+The Nix expressions for the interpreters can be found in `pkgs/development/interpreters/lua-5`.
+
+#### Attributes on lua interpreters packages {#attributes-on-lua-interpreters-packages}
+
+Each interpreter has the following attributes:
+
+- `interpreter`. Alias for `${pkgs.lua}/bin/lua`.
+- `buildEnv`. Function to build lua interpreter environments with extra packages bundled together. See section *lua.buildEnv function* for usage and documentation.
+- `withPackages`. Simpler interface to `buildEnv`.
+- `pkgs`. Set of Lua packages for that specific interpreter. The package set can be modified by overriding the interpreter and passing `packageOverrides`.
+
+#### `buildLuarocksPackage` function {#buildluarockspackage-function}
+
+The `buildLuarocksPackage` function is implemented in `pkgs/development/interpreters/lua-5/build-lua-package.nix`
+The following is an example:
+```nix
+luaposix = buildLuarocksPackage {
+  pname = "luaposix";
+  version = "34.0.4-1";
+
+  src = fetchurl {
+    url    = "https://raw.githubusercontent.com/rocks-moonscript-org/moonrocks-mirror/master/luaposix-34.0.4-1.src.rock";
+    sha256 = "0yrm5cn2iyd0zjd4liyj27srphvy0gjrjx572swar6zqr4dwjqp2";
+  };
+  disabled = (luaOlder "5.1") || (luaAtLeast "5.4");
+  propagatedBuildInputs = [ bit32 lua std_normalize ];
+
+  meta = with lib; {
+    homepage = "https://github.com/luaposix/luaposix/";
+    description = "Lua bindings for POSIX";
+    maintainers = with maintainers; [ vyp lblasc ];
+    license.fullName = "MIT/X11";
+  };
+};
+```
+
+The `buildLuarocksPackage` delegates most tasks to luarocks:
+
+* it adds `luarocks` as an unpacker for `src.rock` files (zip files really).
+* configurePhase` writes a temporary luarocks configuration file which location
+is exported via the environment variable `LUAROCKS_CONFIG`.
+* the `buildPhase` does nothing.
+* `installPhase` calls `luarocks make --deps-mode=none --tree $out` to build and
+install the package
+* In the `postFixup` phase, the `wrapLuaPrograms` bash function is called to
+  wrap all programs in the `$out/bin/*` directory to include `$PATH`
+  environment variable and add dependent libraries to script's `LUA_PATH` and
+  `LUA_CPATH`.
+
+By default `meta.platforms` is set to the same value as the interpreter unless overridden otherwise.
+
+#### `buildLuaApplication` function {#buildluaapplication-function}
+
+The `buildLuaApplication` function is practically the same as `buildLuaPackage`.
+The difference is that `buildLuaPackage` by default prefixes the names of the packages with the version of the interpreter.
+Because with an application we're not interested in multiple version the prefix is dropped.
+
+#### lua.withPackages function {#lua.withpackages-function}
+
+The `lua.withPackages` takes a function as an argument that is passed the set of lua packages and returns the list of packages to be included in the environment.
+Using the `withPackages` function, the previous example for the luafilesystem environment can be written like this:
+
+```nix
+with import <nixpkgs> {};
+
+lua.withPackages (ps: [ps.luafilesystem])
+```
+
+`withPackages` passes the correct package set for the specific interpreter version as an argument to the function. In the above example, `ps` equals `luaPackages`.
+But you can also easily switch to using `lua5_2`:
+
+```nix
+with import <nixpkgs> {};
+
+lua5_2.withPackages (ps: [ps.lua])
+```
+
+Now, `ps` is set to `lua52Packages`, matching the version of the interpreter.
+
+### Possible Todos {#possible-todos}
+
+* export/use version specific variables such as `LUA_PATH_5_2`/`LUAROCKS_CONFIG_5_2`
+* let luarocks check for dependencies via exporting the different rocktrees in temporary config
+
+### Lua Contributing guidelines {#lua-contributing-guidelines}
+
+Following rules should be respected:
+
+* Make sure libraries build for all Lua interpreters.
+* Commit names of Lua libraries should reflect that they are Lua libraries, so write for example `luaPackages.luafilesystem: 1.11 -> 1.12`.

doc/languages-frameworks/maven.section.md

@@ -0,0 +1,351 @@
+# Maven {#maven}
+
+Maven is a well-known build tool for the Java ecosystem however it has some challenges when integrating into the Nix build system.
+
+The following provides a list of common patterns with how to package a Maven project (or any JVM language that can export to Maven) as a Nix package.
+
+For the purposes of this example let's consider a very basic Maven project with the following `pom.xml` with a single dependency on [emoji-java](https://github.com/vdurmont/emoji-java).
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>io.github.fzakaria</groupId>
+  <artifactId>maven-demo</artifactId>
+  <version>1.0</version>
+  <packaging>jar</packaging>
+  <name>NixOS Maven Demo</name>
+
+  <dependencies>
+    <dependency>
+        <groupId>com.vdurmont</groupId>
+        <artifactId>emoji-java</artifactId>
+        <version>5.1.1</version>
+      </dependency>
+  </dependencies>
+</project>
+```
+
+Our main class file will be very simple:
+
+```java
+import com.vdurmont.emoji.EmojiParser;
+
+public class Main {
+  public static void main(String[] args) {
+    String str = "NixOS :grinning: is super cool :smiley:!";
+    String result = EmojiParser.parseToUnicode(str);
+    System.out.println(result);
+  }
+}
+```
+
+You find this demo project at https://github.com/fzakaria/nixos-maven-example
+
+## Solving for dependencies {#solving-for-dependencies}
+
+### buildMaven with NixOS/mvn2nix-maven-plugin {#buildmaven-with-nixosmvn2nix-maven-plugin}
+
+> ⚠️ Although `buildMaven` is the "blessed" way within nixpkgs, as of 2020, it hasn't seen much activity in quite a while.
+
+`buildMaven` is an alternative method that tries to follow similar patterns of other programming languages by generating a lock file. It relies on the maven plugin [mvn2nix-maven-plugin](https://github.com/NixOS/mvn2nix-maven-plugin).
+
+First you generate a `project-info.json` file using the maven plugin.
+
+> This should be executed in the project's source repository or be told which `pom.xml` to execute with.
+
+```bash
+# run this step within the project's source repository
+❯ mvn org.nixos.mvn2nix:mvn2nix-maven-plugin:mvn2nix
+
+❯ cat project-info.json | jq | head
+{
+  "project": {
+    "artifactId": "maven-demo",
+    "groupId": "org.nixos",
+    "version": "1.0",
+    "classifier": "",
+    "extension": "jar",
+    "dependencies": [
+      {
+        "artifactId": "maven-resources-plugin",
+```
+
+This file is then given to the `buildMaven` function, and it returns 2 attributes.
+
+**`repo`**:
+    A Maven repository that is a symlink farm of all the dependencies found in the `project-info.json`
+
+
+**`build`**:
+    A simple derivation that runs through `mvn compile` & `mvn package` to build the JAR. You may use this as inspiration for more complicated derivations.
+
+Here is an [example](https://github.com/fzakaria/nixos-maven-example/blob/main/build-maven-repository.nix) of building the Maven repository
+
+```nix
+{ pkgs ? import <nixpkgs> { } }:
+with pkgs;
+(buildMaven ./project-info.json).repo
+```
+
+The benefit over the _double invocation_ as we will see below, is that the _/nix/store_ entry is a _linkFarm_ of every package, so that changes to your dependency set doesn't involve downloading everything from scratch.
+
+```bash
+❯ tree $(nix-build --no-out-link build-maven-repository.nix) | head
+/nix/store/g87va52nkc8jzbmi1aqdcf2f109r4dvn-maven-repository
+├── antlr
+│   └── antlr
+│       └── 2.7.2
+│           ├── antlr-2.7.2.jar -> /nix/store/d027c8f2cnmj5yrynpbq2s6wmc9cb559-antlr-2.7.2.jar
+│           └── antlr-2.7.2.pom -> /nix/store/mv42fc5gizl8h5g5vpywz1nfiynmzgp2-antlr-2.7.2.pom
+├── avalon-framework
+│   └── avalon-framework
+│       └── 4.1.3
+│           ├── avalon-framework-4.1.3.jar -> /nix/store/iv5fp3955w3nq28ff9xfz86wvxbiw6n9-avalon-framework-4.1.3.jar
+```
+
+### Double Invocation {#double-invocation}
+
+> ⚠️ This pattern is the simplest but may cause unnecessary rebuilds due to the output hash changing.
+
+The double invocation is a _simple_ way to get around the problem that `nix-build` may be sandboxed and have no Internet connectivity.
+
+It treats the entire Maven repository as a single source to be downloaded, relying on Maven's dependency resolution to satisfy the output hash. This is similar to fetchers like `fetchgit`, except it has to run a Maven build to determine what to download.
+
+The first step will be to build the Maven project as a fixed-output derivation in order to collect the Maven repository -- below is an [example](https://github.com/fzakaria/nixos-maven-example/blob/main/double-invocation-repository.nix).
+
+> Traditionally the Maven repository is at `~/.m2/repository`. We will override this to be the `$out` directory.
+
+```nix
+{ lib, stdenv, maven }:
+stdenv.mkDerivation {
+  name = "maven-repository";
+  buildInputs = [ maven ];
+  src = ./.; # or fetchFromGitHub, cleanSourceWith, etc
+  buildPhase = ''
+    mvn package -Dmaven.repo.local=$out
+  '';
+
+  # keep only *.{pom,jar,sha1,nbm} and delete all ephemeral files with lastModified timestamps inside
+  installPhase = ''
+    find $out -type f \
+      -name \*.lastUpdated -or \
+      -name resolver-status.properties -or \
+      -name _remote.repositories \
+      -delete
+  '';
+
+  # don't do any fixup
+  dontFixup = true;
+  outputHashAlgo = "sha256";
+  outputHashMode = "recursive";
+  # replace this with the correct SHA256
+  outputHash = lib.fakeSha256;
+}
+```
+
+The build will fail, and tell you the expected `outputHash` to place. When you've set the hash, the build will return with a `/nix/store` entry whose contents are the full Maven repository.
+
+> Some additional files are deleted that would cause the output hash to change potentially on subsequent runs.
+
+```bash
+❯ tree $(nix-build --no-out-link double-invocation-repository.nix) | head
+/nix/store/8kicxzp98j68xyi9gl6jda67hp3c54fq-maven-repository
+├── backport-util-concurrent
+│   └── backport-util-concurrent
+│       └── 3.1
+│           ├── backport-util-concurrent-3.1.pom
+│           └── backport-util-concurrent-3.1.pom.sha1
+├── classworlds
+│   └── classworlds
+│       ├── 1.1
+│       │   ├── classworlds-1.1.jar
+```
+
+If your package uses _SNAPSHOT_ dependencies or _version ranges_; there is a strong likelihood that over-time your output hash will change since the resolved dependencies may change. Hence this method is less recommended then using `buildMaven`.
+
+## Building a JAR {#building-a-jar}
+
+Regardless of which strategy is chosen above, the step to build the derivation is the same.
+
+```nix
+{ stdenv, maven, callPackage }:
+# pick a repository derivation, here we will use buildMaven
+let repository = callPackage ./build-maven-repository.nix { };
+in stdenv.mkDerivation rec {
+  pname = "maven-demo";
+  version = "1.0";
+
+  src = builtins.fetchTarball "https://github.com/fzakaria/nixos-maven-example/archive/main.tar.gz";
+  buildInputs = [ maven ];
+
+  buildPhase = ''
+    echo "Using repository ${repository}"
+    mvn --offline -Dmaven.repo.local=${repository} package;
+  '';
+
+  installPhase = ''
+    install -Dm644 target/${pname}-${version}.jar $out/share/java
+  '';
+}
+```
+
+> We place the library in `$out/share/java` since JDK package has a _stdenv setup hook_ that adds any JARs in the `share/java` directories of the build inputs to the CLASSPATH environment.
+
+```bash
+❯ tree $(nix-build --no-out-link build-jar.nix)
+/nix/store/7jw3xdfagkc2vw8wrsdv68qpsnrxgvky-maven-demo-1.0
+└── share
+    └── java
+        └── maven-demo-1.0.jar
+
+2 directories, 1 file
+```
+
+## Runnable JAR {#runnable-jar}
+
+The previous example builds a `jar` file but that's not a file one can run.
+
+You need to use it with `java -jar $out/share/java/output.jar` and make sure to provide the required dependencies on the classpath.
+
+The following explains how to use `makeWrapper` in order to make the derivation produce an executable that will run the JAR file you created.
+
+We will use the same repository we built above (either _double invocation_ or _buildMaven_) to setup a CLASSPATH for our JAR.
+
+The following two methods are more suited to Nix then building an [UberJar](https://imagej.net/Uber-JAR) which may be the more traditional approach.
+
+### CLASSPATH {#classpath}
+
+> This is ideal if you are providing a derivation for _nixpkgs_ and don't want to patch the project's `pom.xml`.
+
+We will read the Maven repository and flatten it to a single list. This list will then be concatenated with the _CLASSPATH_ separator to create the full classpath.
+
+We make sure to provide this classpath to the `makeWrapper`.
+
+```nix
+{ stdenv, maven, callPackage, makeWrapper, jre }:
+let
+  repository = callPackage ./build-maven-repository.nix { };
+in stdenv.mkDerivation rec {
+  pname = "maven-demo";
+  version = "1.0";
+
+  src = builtins.fetchTarball
+    "https://github.com/fzakaria/nixos-maven-example/archive/main.tar.gz";
+  buildInputs = [ maven makeWrapper ];
+
+  buildPhase = ''
+    echo "Using repository ${repository}"
+    mvn --offline -Dmaven.repo.local=${repository} package;
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+
+    classpath=$(find ${repository} -name "*.jar" -printf ':%h/%f');
+    install -Dm644 target/${pname}-${version}.jar $out/share/java
+    # create a wrapper that will automatically set the classpath
+    # this should be the paths from the dependency derivation
+    makeWrapper ${jre}/bin/java $out/bin/${pname} \
+          --add-flags "-classpath $out/share/java/${pname}-${version}.jar:''${classpath#:}" \
+          --add-flags "Main"
+  '';
+}
+```
+
+### MANIFEST file via Maven Plugin {#manifest-file-via-maven-plugin}
+
+> This is ideal if you are the project owner and want to change your `pom.xml` to set the CLASSPATH within it.
+
+Augment the `pom.xml` to create a JAR with the following manifest:
+
+```xml
+<build>
+  <plugins>
+    <plugin>
+        <artifactId>maven-jar-plugin</artifactId>
+        <configuration>
+            <archive>
+                <manifest>
+                    <addClasspath>true</addClasspath>
+                    <classpathPrefix>../../repository/</classpathPrefix>
+                    <classpathLayoutType>repository</classpathLayoutType>
+                    <mainClass>Main</mainClass>
+                </manifest>
+                <manifestEntries>
+                    <Class-Path>.</Class-Path>
+                </manifestEntries>
+            </archive>
+        </configuration>
+    </plugin>
+  </plugins>
+</build>
+```
+
+The above plugin instructs the JAR to look for the necessary dependencies in the `lib/` relative folder. The layout of the folder is also in the _maven repository_ style.
+
+```bash
+❯ unzip -q -c $(nix-build --no-out-link runnable-jar.nix)/share/java/maven-demo-1.0.jar META-INF/MANIFEST.MF
+
+Manifest-Version: 1.0
+Archiver-Version: Plexus Archiver
+Built-By: nixbld
+Class-Path: . ../../repository/com/vdurmont/emoji-java/5.1.1/emoji-jav
+ a-5.1.1.jar ../../repository/org/json/json/20170516/json-20170516.jar
+Created-By: Apache Maven 3.6.3
+Build-Jdk: 1.8.0_265
+Main-Class: Main
+```
+
+We will modify the derivation above to add a symlink to our repository so that it's accessible to our JAR during the `installPhase`.
+
+```nix
+{ stdenv, maven, callPackage, makeWrapper, jre }:
+# pick a repository derivation, here we will use buildMaven
+let repository = callPackage ./build-maven-repository.nix { };
+in stdenv.mkDerivation rec {
+  pname = "maven-demo";
+  version = "1.0";
+
+  src = builtins.fetchTarball
+    "https://github.com/fzakaria/nixos-maven-example/archive/main.tar.gz";
+  buildInputs = [ maven makeWrapper ];
+
+  buildPhase = ''
+    echo "Using repository ${repository}"
+    mvn --offline -Dmaven.repo.local=${repository} package;
+  '';
+
+  installPhase = ''
+    mkdir -p $out/bin
+
+    # create a symbolic link for the repository directory
+    ln -s ${repository} $out/repository
+
+    install -Dm644 target/${pname}-${version}.jar $out/share/java
+    # create a wrapper that will automatically set the classpath
+    # this should be the paths from the dependency derivation
+    makeWrapper ${jre}/bin/java $out/bin/${pname} \
+          --add-flags "-jar $out/share/java/${pname}-${version}.jar"
+  '';
+}
+```
+
+> Our script produces a dependency on `jre` rather than `jdk` to restrict the runtime closure necessary to run the application.
+
+This will give you an executable shell-script that launches your JAR with all the dependencies available.
+
+```bash
+❯ tree $(nix-build --no-out-link runnable-jar.nix)
+/nix/store/8d4c3ibw8ynsn01ibhyqmc1zhzz75s26-maven-demo-1.0
+├── bin
+│   └── maven-demo
+├── repository -> /nix/store/g87va52nkc8jzbmi1aqdcf2f109r4dvn-maven-repository
+└── share
+    └── java
+        └── maven-demo-1.0.jar
+
+❯ $(nix-build --no-out-link --option tarball-ttl 1 runnable-jar.nix)/bin/maven-demo
+NixOS 😀 is super cool 😃!
+```

doc/languages-frameworks/nim.section.md

@@ -0,0 +1,91 @@
+# Nim {#nim}
+
+## Overview {#nim-overview}
+
+The Nim compiler, a builder function, and some packaged libraries are available
+in Nixpkgs. Until now each compiler release has been effectively backwards
+compatible so only the latest version is available.
+
+## Nim program packages in Nixpkgs {#nim-program-packages-in-nixpkgs}
+
+Nim programs can be built using `nimPackages.buildNimPackage`. In the
+case of packages not containing exported library code the attribute
+`nimBinOnly` should be set to `true`.
+
+The following example shows a Nim program that depends only on Nim libraries:
+
+```nix
+{ lib, nimPackages, fetchurl }:
+
+nimPackages.buildNimPackage rec {
+  pname = "hottext";
+  version = "1.4";
+
+  nimBinOnly = true;
+
+  src = fetchurl {
+    url = "https://git.sr.ht/~ehmry/hottext/archive/v${version}.tar.gz";
+    sha256 = "sha256-hIUofi81zowSMbt1lUsxCnVzfJGN3FEiTtN8CEFpwzY=";
+  };
+
+  buildInputs = with nimPackages; [
+    bumpy
+    chroma
+    flatty
+    nimsimd
+    pixie
+    sdl2
+    typography
+    vmath
+    zippy
+  ];
+}
+
+```
+
+## Nim library packages in Nixpkgs {#nim-library-packages-in-nixpkgs}
+
+
+Nim libraries can also be built using `nimPackages.buildNimPackage`, but
+often the product of a fetcher is sufficient to satisfy a dependency.
+The `fetchgit`, `fetchFromGitHub`, and `fetchNimble` functions yield an
+output that can be discovered during the `configurePhase` of `buildNimPackage`.
+
+Nim library packages are listed in
+[pkgs/top-level/nim-packages.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/nim-packages.nix) and implemented at
+[pkgs/development/nim-packages](https://github.com/NixOS/nixpkgs/tree/master/pkgs/development/nim-packages).
+
+The following example shows a Nim library that propagates a dependency on a
+non-Nim package:
+```nix
+{ lib, buildNimPackage, fetchNimble, SDL2 }:
+
+buildNimPackage rec {
+  pname = "sdl2";
+  version = "2.0.4";
+  src = fetchNimble {
+    inherit pname version;
+    hash = "sha256-Vtcj8goI4zZPQs2TbFoBFlcR5UqDtOldaXSH/+/xULk=";
+  };
+  propagatedBuildInputs = [ SDL2 ];
+}
+```
+
+## `buildNimPackage` parameters {#buildnimpackage-parameters}
+
+All parameters from `stdenv.mkDerivation` function are still supported. The
+following are specific to `buildNimPackage`:
+
+* `nimBinOnly ? false`: If `true` then build only the programs listed in
+  the Nimble file in the packages sources.
+* `nimbleFile`: Specify the Nimble file location of the package being built
+  rather than discover the file at build-time.
+* `nimRelease ? true`: Build the package in *release* mode.
+* `nimDefines ? []`: A list of Nim defines. Key-value tuples are not supported.
+* `nimFlags ? []`: A list of command line arguments to pass to the Nim compiler.
+  Use this to specify defines with arguments in the form of `-d:${name}=${value}`.
+* `nimDoc` ? false`: Build and install HTML documentation.
+
+* `buildInputs` ? []: The packages listed here will be searched for `*.nimble`
+  files which are used to populate the Nim library path. Otherwise the standard
+  behavior is in effect.

doc/languages-frameworks/ocaml.section.md

@@ -0,0 +1,131 @@
+# OCaml {#sec-language-ocaml}
+
+## User guide {#sec-language-ocaml-user-guide}
+
+OCaml libraries are available in attribute sets of the form `ocaml-ng.ocamlPackages_X_XX` where X is to be replaced with the desired compiler version. For example, ocamlgraph compiled with OCaml 4.12 can be found in `ocaml-ng.ocamlPackages_4_12.ocamlgraph`. The compiler itself is also located in this set, under the name `ocaml`.
+
+If you don't care about the exact compiler version, `ocamlPackages` is a top-level alias pointing to a recent version of OCaml.
+
+OCaml applications are usually available top-level, and not inside `ocamlPackages`. Notable exceptions are build tools that must be built with the same compiler version as the compiler you intend to use like `dune` or `ocaml-lsp`.
+
+To open a shell able to build a typical OCaml project, put the dependencies in `buildInputs` and add `ocamlPackages.ocaml` and `ocamlPackages.findlib` to `nativeBuildInputs` at least.
+For example:
+```nix
+let
+ pkgs = import <nixpkgs> {};
+ # choose the ocaml version you want to use
+ ocamlPackages = pkgs.ocaml-ng.ocamlPackages_4_12;
+in
+pkgs.mkShell {
+  # build tools
+  nativeBuildInputs = with ocamlPackages; [ ocaml findlib dune_2 ocaml-lsp ];
+  # dependencies
+  buildInputs = with ocamlPackages; [ ocamlgraph ];
+}
+```
+
+## Packaging guide {#sec-language-ocaml-packaging}
+
+OCaml libraries should be installed in `$(out)/lib/ocaml/${ocaml.version}/site-lib/`. Such directories are automatically added to the `$OCAMLPATH` environment variable when building another package that depends on them or when opening a `nix-shell`.
+
+Given that most of the OCaml ecosystem is now built with dune, nixpkgs includes a convenience build support function called `buildDunePackage` that will build an OCaml package using dune, OCaml and findlib and any additional dependencies provided as `buildInputs` or `propagatedBuildInputs`.
+
+Here is a simple package example.
+
+- It defines an (optional) attribute `minimalOCamlVersion` (see note below)
+  that will be used to throw a descriptive evaluation error if building with
+  an older OCaml is attempted.
+
+- It uses the `fetchFromGitHub` fetcher to get its source.
+
+- `duneVersion = "2"` ensures that Dune version 2 is used for the
+  build (this is the default; valid values are `"1"`, `"2"`, and `"3"`);
+  note that there is also a legacy `useDune2` boolean attribute:
+  set to `false` it corresponds to `duneVersion = "1"`; set to `true` it
+  corresponds to `duneVersion = "2"`. If both arguments (`duneVersion` and
+  `useDune2`) are given, the second one (`useDune2`) is silently ignored.
+
+- It sets the optional `doCheck` attribute such that tests will be run with
+  `dune runtest -p angstrom` after the build (`dune build -p angstrom`) is
+  complete, but only if the Ocaml version is at at least `"4.05"`.
+
+- It uses the package `ocaml-syntax-shims` as a build input, `alcotest` and
+  `ppx_let` as check inputs (because they are needed to run the tests), and
+  `bigstringaf` and `result` as propagated build inputs (thus they will also be
+  available to libraries depending on this library).
+
+- The library will be installed using the `angstrom.install` file that dune
+  generates.
+
+```nix
+{ lib,
+  fetchFromGitHub,
+  buildDunePackage,
+  ocaml,
+  ocaml-syntax-shims,
+  alcotest,
+  result,
+  bigstringaf,
+  ppx_let }:
+
+buildDunePackage rec {
+  pname = "angstrom";
+  version = "0.15.0";
+  duneVersion = "2";
+
+  minimalOCamlVersion = "4.04";
+
+  src = fetchFromGitHub {
+    owner  = "inhabitedtype";
+    repo   = pname;
+    rev    = version;
+    sha256 = "1hmrkdcdlkwy7rxhngf3cv3sa61cznnd9p5lmqhx20664gx2ibrh";
+  };
+
+  checkInputs = [ alcotest ppx_let ];
+  buildInputs = [ ocaml-syntax-shims ];
+  propagatedBuildInputs = [ bigstringaf result ];
+  doCheck = lib.versionAtLeast ocaml.version "4.05";
+
+  meta = {
+    homepage = "https://github.com/inhabitedtype/angstrom";
+    description = "OCaml parser combinators built for speed and memory efficiency";
+    license = lib.licenses.bsd3;
+    maintainers = with lib.maintainers; [ sternenseemann ];
+  };
+```
+
+Here is a second example, this time using a source archive generated with `dune-release`. It is a good idea to use this archive when it is available as it will usually contain substituted variables such as a `%%VERSION%%` field. This library does not depend on any other OCaml library and no tests are run after building it.
+
+```nix
+{ lib, fetchurl, buildDunePackage }:
+
+buildDunePackage rec {
+  pname = "wtf8";
+  version = "1.0.2";
+
+  useDune2 = true;
+
+  minimalOCamlVersion = "4.02";
+
+  src = fetchurl {
+    url = "https://github.com/flowtype/ocaml-${pname}/releases/download/v${version}/${pname}-v${version}.tbz";
+    sha256 = "09ygcxxd5warkdzz17rgpidrd0pg14cy2svvnvy1hna080lzg7vp";
+  };
+
+  meta = with lib; {
+    homepage = "https://github.com/flowtype/ocaml-wtf8";
+    description = "WTF-8 is a superset of UTF-8 that allows unpaired surrogates.";
+    license = licenses.mit;
+    maintainers = [ maintainers.eqyiel ];
+  };
+}
+```
+
+Note about `minimalOCamlVersion`.  A deprecated version of this argument was
+spelled `minimumOCamlVersion`; setting the old attribute wrongly modifies the
+derivation hash and is therefore inappropriate. As a technical dept, currently
+packaged libraries may still use the old spelling: maintainers are invited to
+fix this when updating packages. Massive renaming is strongly discouraged as it
+would be challenging to review, difficult to test, and will cause unnecessary
+rebuild.

doc/languages-frameworks/octave.section.md

@@ -0,0 +1,92 @@
+# Octave {#sec-octave}
+
+## Introduction {#ssec-octave-introduction}
+
+Octave is a modular scientific programming language and environment.
+A majority of the packages supported by Octave from their [website](https://octave.sourceforge.io/packages.php) are packaged in nixpkgs.
+
+## Structure {#ssec-octave-structure}
+
+All Octave add-on packages are available in two ways:
+1. Under the top-level `Octave` attribute, `octave.pkgs`.
+2. As a top-level attribute, `octavePackages`.
+
+## Packaging Octave Packages {#ssec-octave-packaging}
+
+Nixpkgs provides a function `buildOctavePackage`, a generic package builder function for any Octave package that complies with the Octave's current packaging format.
+
+All Octave packages are defined in [pkgs/top-level/octave-packages.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/octave-packages.nix) rather than `pkgs/all-packages.nix`.
+Each package is defined in their own file in the [pkgs/development/octave-modules](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/octave-modules) directory.
+Octave packages are made available through `all-packages.nix` through both the attribute `octavePackages` and `octave.pkgs`.
+You can test building an Octave package as follows:
+
+```ShellSession
+$ nix-build -A octavePackages.symbolic
+```
+
+To install it into your user profile, run this command from the root of the repository:
+
+```ShellSession
+$ nix-env -f. -iA octavePackages.symbolic
+```
+
+You can build Octave with packages by using the `withPackages` passed-through function.
+
+```ShellSession
+$ nix-shell -p 'octave.withPackages (ps: with ps; [ symbolic ])'
+```
+
+This will also work in a `shell.nix` file.
+
+```nix
+{ pkgs ? import <nixpkgs> { }}:
+
+pkgs.mkShell {
+  nativeBuildInputs = with pkgs; [
+    (octave.withPackages (opkgs: with opkgs; [ symbolic ]))
+  ];
+}
+```
+
+### `buildOctavePackage` Steps {#sssec-buildOctavePackage-steps}
+
+The `buildOctavePackage` does several things to make sure things work properly.
+
+1. Sets the environment variable `OCTAVE_HISTFILE` to `/dev/null` during package compilation so that the commands run through the Octave interpreter directly are not logged.
+2. Skips the configuration step, because the packages are stored as gzipped tarballs, which Octave itself handles directly.
+3. Change the hierarchy of the tarball so that only a single directory is at the top-most level of the tarball.
+4. Use Octave itself to run the `pkg build` command, which unzips the tarball, extracts the necessary files written in Octave, and compiles any code written in C++ or Fortran, and places the fully compiled artifact in `$out`.
+
+`buildOctavePackage` is built on top of `stdenv` in a standard way, allowing most things to be customized.
+
+### Handling Dependencies {#sssec-octave-handling-dependencies}
+
+In Octave packages, there are four sets of dependencies that can be specified:
+
+`nativeBuildInputs`
+: Just like other packages, `nativeBuildInputs` is intended for architecture-dependent build-time-only dependencies.
+
+`buildInputs`
+: Like other packages, `buildInputs` is intended for architecture-independent build-time-only dependencies.
+
+`propagatedBuildInputs`
+: Similar to other packages, `propagatedBuildInputs` is intended for packages that are required for both building and running of the package.
+See [Symbolic](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/octave-modules/symbolic/default.nix) for how this works and why it is needed.
+
+`requiredOctavePackages`
+: This is a special dependency that ensures the specified Octave packages are dependent on others, and are made available simultaneously when loading them in Octave.
+
+### Installing Octave Packages {#sssec-installing-octave-packages}
+
+By default, the `buildOctavePackage` function does _not_ install the requested package into Octave for use.
+The function will only build the requested package.
+This is due to Octave maintaining an text-based database about which packages are installed where.
+To this end, when all the requested packages have been built, the Octave package and all its add-on packages are put together into an environment, similar to Python.
+
+1. First, all the Octave binaries are wrapped with the environment variable `OCTAVE_SITE_INITFILE` set to a file in `$out`, which is required for Octave to be able to find the non-standard package database location.
+2. Because of the way `buildEnv` works, all tarballs that are present (which should be all Octave packages to install) should be removed.
+3. The path down to the default install location of Octave packages is recreated so that Nix-operated Octave can install the packages.
+4. Install the packages into the `$out` environment while writing package entries to the database file.
+This database file is unique for each different (according to Nix) environment invocation.
+5. Rewrite the Octave-wide startup file to read from the list of packages installed in that particular environment.
+6. Wrap any programs that are required by the Octave packages so that they work with all the paths defined within the environment.

doc/languages-frameworks/perl.section.md

@@ -0,0 +1,159 @@
+# Perl {#sec-language-perl}
+
+## Running perl programs on the shell {#ssec-perl-running}
+
+When executing a Perl script, it is possible you get an error such as `./myscript.pl: bad interpreter: /usr/bin/perl: no such file or directory`. This happens when the script expects Perl to be installed at `/usr/bin/perl`, which is not the case when using Perl from nixpkgs. You can fix the script by changing the first line to:
+
+```perl
+#!/usr/bin/env perl
+```
+
+to take the Perl installation from the `PATH` environment variable, or invoke Perl directly with:
+
+```ShellSession
+$ perl ./myscript.pl
+```
+
+When the script is using a Perl library that is not installed globally, you might get an error such as `Can't locate DB_File.pm in @INC (you may need to install the DB_File module)`. In that case, you can use `nix-shell` to start an ad-hoc shell with that library installed, for instance:
+
+```ShellSession
+$ nix-shell -p perl perlPackages.DBFile --run ./myscript.pl
+```
+
+If you are always using the script in places where `nix-shell` is available, you can embed the `nix-shell` invocation in the shebang like this:
+
+```perl
+#!/usr/bin/env nix-shell
+#! nix-shell -i perl -p perl perlPackages.DBFile
+```
+
+## Packaging Perl programs {#ssec-perl-packaging}
+
+Nixpkgs provides a function `buildPerlPackage`, a generic package builder function for any Perl package that has a standard `Makefile.PL`. It’s implemented in [pkgs/development/perl-modules/generic](https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/perl-modules/generic).
+
+Perl packages from CPAN are defined in [pkgs/top-level/perl-packages.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/perl-packages.nix) rather than `pkgs/all-packages.nix`. Most Perl packages are so straight-forward to build that they are defined here directly, rather than having a separate function for each package called from `perl-packages.nix`. However, more complicated packages should be put in a separate file, typically in `pkgs/development/perl-modules`. Here is an example of the former:
+
+```nix
+ClassC3 = buildPerlPackage rec {
+  name = "Class-C3-0.21";
+  src = fetchurl {
+    url = "mirror://cpan/authors/id/F/FL/FLORA/${name}.tar.gz";
+    sha256 = "1bl8z095y4js66pwxnm7s853pi9czala4sqc743fdlnk27kq94gz";
+  };
+};
+```
+
+Note the use of `mirror://cpan/`, and the `${name}` in the URL definition to ensure that the name attribute is consistent with the source that we’re actually downloading. Perl packages are made available in `all-packages.nix` through the variable `perlPackages`. For instance, if you have a package that needs `ClassC3`, you would typically write
+
+```nix
+foo = import ../path/to/foo.nix {
+  inherit stdenv fetchurl ...;
+  inherit (perlPackages) ClassC3;
+};
+```
+
+in `all-packages.nix`. You can test building a Perl package as follows:
+
+```ShellSession
+$ nix-build -A perlPackages.ClassC3
+```
+
+To install it with `nix-env` instead: `nix-env -f. -iA perlPackages.ClassC3`.
+
+So what does `buildPerlPackage` do? It does the following:
+
+1. In the configure phase, it calls `perl Makefile.PL` to generate a Makefile. You can set the variable `makeMakerFlags` to pass flags to `Makefile.PL`
+2. It adds the contents of the `PERL5LIB` environment variable to `#! .../bin/perl` line of Perl scripts as `-Idir` flags. This ensures that a script can find its dependencies. (This can cause this shebang line to become too long for Darwin to handle; see the note below.)
+3. In the fixup phase, it writes the propagated build inputs (`propagatedBuildInputs`) to the file `$out/nix-support/propagated-user-env-packages`. `nix-env` recursively installs all packages listed in this file when you install a package that has it. This ensures that a Perl package can find its dependencies.
+
+`buildPerlPackage` is built on top of `stdenv`, so everything can be customised in the usual way. For instance, the `BerkeleyDB` module has a `preConfigure` hook to generate a configuration file used by `Makefile.PL`:
+
+```nix
+{ buildPerlPackage, fetchurl, db }:
+
+buildPerlPackage rec {
+  name = "BerkeleyDB-0.36";
+
+  src = fetchurl {
+    url = "mirror://cpan/authors/id/P/PM/PMQS/${name}.tar.gz";
+    sha256 = "07xf50riarb60l1h6m2dqmql8q5dij619712fsgw7ach04d8g3z1";
+  };
+
+  preConfigure = ''
+    echo "LIB = ${db.out}/lib" > config.in
+    echo "INCLUDE = ${db.dev}/include" >> config.in
+  '';
+}
+```
+
+Dependencies on other Perl packages can be specified in the `buildInputs` and `propagatedBuildInputs` attributes. If something is exclusively a build-time dependency, use `buildInputs`; if it’s (also) a runtime dependency, use `propagatedBuildInputs`. For instance, this builds a Perl module that has runtime dependencies on a bunch of other modules:
+
+```nix
+ClassC3Componentised = buildPerlPackage rec {
+  name = "Class-C3-Componentised-1.0004";
+  src = fetchurl {
+    url = "mirror://cpan/authors/id/A/AS/ASH/${name}.tar.gz";
+    sha256 = "0xql73jkcdbq4q9m0b0rnca6nrlvf5hyzy8is0crdk65bynvs8q1";
+  };
+  propagatedBuildInputs = [
+    ClassC3 ClassInspector TestException MROCompat
+  ];
+};
+```
+
+On Darwin, if a script has too many `-Idir` flags in its first line (its “shebang line”), it will not run. This can be worked around by calling the `shortenPerlShebang` function from the `postInstall` phase:
+
+```nix
+{ lib, stdenv, buildPerlPackage, fetchurl, shortenPerlShebang }:
+
+ImageExifTool = buildPerlPackage {
+  pname = "Image-ExifTool";
+  version = "11.50";
+
+  src = fetchurl {
+    url = "https://www.sno.phy.queensu.ca/~phil/exiftool/Image-ExifTool-11.50.tar.gz";
+    sha256 = "0d8v48y94z8maxkmw1rv7v9m0jg2dc8xbp581njb6yhr7abwqdv3";
+  };
+
+  buildInputs = lib.optional stdenv.isDarwin shortenPerlShebang;
+  postInstall = lib.optionalString stdenv.isDarwin ''
+    shortenPerlShebang $out/bin/exiftool
+  '';
+};
+```
+
+This will remove the `-I` flags from the shebang line, rewrite them in the `use lib` form, and put them on the next line instead. This function can be given any number of Perl scripts as arguments; it will modify them in-place.
+
+### Generation from CPAN {#ssec-generation-from-CPAN}
+
+Nix expressions for Perl packages can be generated (almost) automatically from CPAN. This is done by the program `nix-generate-from-cpan`, which can be installed as follows:
+
+```ShellSession
+$ nix-env -f "<nixpkgs>" -iA nix-generate-from-cpan
+```
+
+Substitute `<nixpkgs>` by the path of a nixpkgs clone to use the latest version.
+
+This program takes a Perl module name, looks it up on CPAN, fetches and unpacks the corresponding package, and prints a Nix expression on standard output. For example:
+
+```ShellSession
+$ nix-generate-from-cpan XML::Simple
+  XMLSimple = buildPerlPackage rec {
+    name = "XML-Simple-2.22";
+    src = fetchurl {
+      url = "mirror://cpan/authors/id/G/GR/GRANTM/${name}.tar.gz";
+      sha256 = "b9450ef22ea9644ae5d6ada086dc4300fa105be050a2030ebd4efd28c198eb49";
+    };
+    propagatedBuildInputs = [ XMLNamespaceSupport XMLSAX XMLSAXExpat ];
+    meta = {
+      description = "An API for simple XML files";
+      license = with lib.licenses; [ artistic1 gpl1Plus ];
+    };
+  };
+```
+
+The output can be pasted into `pkgs/top-level/perl-packages.nix` or wherever else you need it.
+
+### Cross-compiling modules {#ssec-perl-cross-compilation}
+
+Nixpkgs has experimental support for cross-compiling Perl modules. In many cases, it will just work out of the box, even for modules with native extensions. Sometimes, however, the Makefile.PL for a module may (indirectly) import a native module. In that case, you will need to make a stub for that module that will satisfy the Makefile.PL and install it into `lib/perl5/site_perl/cross_perl/${perl.version}`. See the `postInstall` for `DBI` for an example.

doc/languages-frameworks/php.section.md

@@ -0,0 +1,155 @@
+# PHP {#sec-php}
+
+## User Guide {#ssec-php-user-guide}
+
+### Overview {#ssec-php-user-guide-overview}
+
+Several versions of PHP are available on Nix, each of which having a
+wide variety of extensions and libraries available.
+
+The different versions of PHP that nixpkgs provides are located under
+attributes named based on major and minor version number; e.g.,
+`php74` is PHP 7.4.
+
+Only versions of PHP that are supported by upstream for the entirety
+of a given NixOS release will be included in that release of
+NixOS. See [PHP Supported
+Versions](https://www.php.net/supported-versions.php).
+
+The attribute `php` refers to the version of PHP considered most
+stable and thoroughly tested in nixpkgs for any given release of
+NixOS - not necessarily the latest major release from upstream.
+
+All available PHP attributes are wrappers around their respective
+binary PHP package and provide commonly used extensions this way. The
+real PHP 7.4 package, i.e. the unwrapped one, is available as
+`php74.unwrapped`; see the next section for more details.
+
+Interactive tools built on PHP are put in `php.packages`; composer is
+for example available at `php.packages.composer`.
+
+Most extensions that come with PHP, as well as some popular
+third-party ones, are available in `php.extensions`; for example, the
+opcache extension shipped with PHP is available at
+`php.extensions.opcache` and the third-party ImageMagick extension at
+`php.extensions.imagick`.
+
+### Installing PHP with extensions {#ssec-php-user-guide-installing-with-extensions}
+
+A PHP package with specific extensions enabled can be built using
+`php.withExtensions`. This is a function which accepts an anonymous
+function as its only argument; the function should accept two named
+parameters: `enabled` - a list of currently enabled extensions and
+`all` - the set of all extensions, and return a list of wanted
+extensions. For example, a PHP package with all default extensions and
+ImageMagick enabled:
+
+```nix
+php.withExtensions ({ enabled, all }:
+  enabled ++ [ all.imagick ])
+```
+
+To exclude some, but not all, of the default extensions, you can
+filter the `enabled` list like this:
+
+```nix
+php.withExtensions ({ enabled, all }:
+  (lib.filter (e: e != php.extensions.opcache) enabled)
+  ++ [ all.imagick ])
+```
+
+To build your list of extensions from the ground up, you can simply
+ignore `enabled`:
+
+```nix
+php.withExtensions ({ all, ... }: with all; [ imagick opcache ])
+```
+
+`php.withExtensions` provides extensions by wrapping a minimal php
+base package, providing a `php.ini` file listing all extensions to be
+loaded. You can access this package through the `php.unwrapped`
+attribute; useful if you, for example, need access to the `dev`
+output. The generated `php.ini` file can be accessed through the
+`php.phpIni` attribute.
+
+If you want a PHP build with extra configuration in the `php.ini`
+file, you can use `php.buildEnv`. This function takes two named and
+optional parameters: `extensions` and `extraConfig`. `extensions`
+takes an extension specification equivalent to that of
+`php.withExtensions`, `extraConfig` a string of additional `php.ini`
+configuration parameters. For example, a PHP package with the opcache
+and ImageMagick extensions enabled, and `memory_limit` set to `256M`:
+
+```nix
+php.buildEnv {
+  extensions = { all, ... }: with all; [ imagick opcache ];
+  extraConfig = "memory_limit=256M";
+}
+```
+
+#### Example setup for `phpfpm` {#ssec-php-user-guide-installing-with-extensions-phpfpm}
+
+You can use the previous examples in a `phpfpm` pool called `foo` as
+follows:
+
+```nix
+let
+  myPhp = php.withExtensions ({ all, ... }: with all; [ imagick opcache ]);
+in {
+  services.phpfpm.pools."foo".phpPackage = myPhp;
+};
+```
+
+```nix
+let
+  myPhp = php.buildEnv {
+    extensions = { all, ... }: with all; [ imagick opcache ];
+    extraConfig = "memory_limit=256M";
+  };
+in {
+  services.phpfpm.pools."foo".phpPackage = myPhp;
+};
+```
+
+#### Example usage with `nix-shell` {#ssec-php-user-guide-installing-with-extensions-nix-shell}
+
+This brings up a temporary environment that contains a PHP interpreter
+with the extensions `imagick` and `opcache` enabled:
+
+```sh
+nix-shell -p 'php.withExtensions ({ all, ... }: with all; [ imagick opcache ])'
+```
+
+### Installing PHP packages with extensions {#ssec-php-user-guide-installing-packages-with-extensions}
+
+All interactive tools use the PHP package you get them from, so all
+packages at `php.packages.*` use the `php` package with its default
+extensions. Sometimes this default set of extensions isn't enough and
+you may want to extend it. A common case of this is the `composer`
+package: a project may depend on certain extensions and `composer`
+won't work with that project unless those extensions are loaded.
+
+Example of building `composer` with additional extensions:
+```nix
+(php.withExtensions ({ all, enabled }:
+  enabled ++ (with all; [ imagick redis ]))
+).packages.composer
+```
+
+### Overriding PHP packages {#ssec-php-user-guide-overriding-packages}
+
+`php-packages.nix` form a scope, allowing us to override the packages defined within. For example, to apply a patch to a `mysqlnd` extension, you can simply pass an overlay-style function to `php`’s `packageOverrides` argument:
+
+```nix
+php.override {
+  packageOverrides = final: prev: {
+    extensions = prev.extensions // {
+      mysqlnd = prev.extensions.mysqlnd.overrideAttrs (attrs: {
+        patches = attrs.patches or [] ++ [
+          …
+        ];
+      });
+    };
+  };
+}
+```

doc/languages-frameworks/qt.section.md

@@ -0,0 +1,160 @@
+# Qt {#sec-language-qt}
+
+Writing Nix expressions for Qt libraries and applications is largely similar as for other C++ software.
+This section assumes some knowledge of the latter.
+There are two problems that the Nixpkgs Qt infrastructure addresses,
+which are not shared by other C++ software:
+
+1.  There are usually multiple supported versions of Qt in Nixpkgs.
+    All of a package's dependencies must be built with the same version of Qt.
+    This is similar to the version constraints imposed on interpreted languages like Python.
+2.  Qt makes extensive use of runtime dependency detection.
+    Runtime dependencies are made into build dependencies through wrappers.
+
+## Nix expression for a Qt package (default.nix) {#qt-default-nix}
+
+```{=docbook}
+<programlisting>
+{ stdenv, lib, qtbase, wrapQtAppsHook }: <co xml:id='qt-default-nix-co-1' />
+
+stdenv.mkDerivation {
+  pname = "myapp";
+  version = "1.0";
+
+  buildInputs = [ qtbase ];
+  nativeBuildInputs = [ wrapQtAppsHook ]; <co xml:id='qt-default-nix-co-2' />
+}
+</programlisting>
+
+ <calloutlist>
+  <callout arearefs='qt-default-nix-co-1'>
+   <para>
+    Import Qt modules directly, that is: <literal>qtbase</literal>, <literal>qtdeclarative</literal>, etc.
+    <emphasis>Do not</emphasis> import Qt package sets such as <literal>qt5</literal>
+    because the Qt versions of dependencies may not be coherent, causing build and runtime failures.
+   </para>
+  </callout>
+  <callout arearefs='qt-default-nix-co-2'>
+    <para>
+      All Qt packages must include <literal>wrapQtAppsHook</literal> in
+      <literal>nativeBuildInputs</literal>, or you must explicitly set
+      <literal>dontWrapQtApps</literal>.
+    </para>
+  </callout>
+ </calloutlist>
+```
+
+## Locating runtime dependencies {#qt-runtime-dependencies}
+
+Qt applications must be wrapped to find runtime dependencies.
+Include `wrapQtAppsHook` in `nativeBuildInputs`:
+
+```nix
+{ stdenv, wrapQtAppsHook }:
+
+stdenv.mkDerivation {
+  # ...
+  nativeBuildInputs = [ wrapQtAppsHook ];
+}
+```
+
+Add entries to `qtWrapperArgs` are to modify the wrappers created by
+`wrapQtAppsHook`:
+
+```nix
+{ stdenv, wrapQtAppsHook }:
+
+stdenv.mkDerivation {
+  # ...
+  nativeBuildInputs = [ wrapQtAppsHook ];
+  qtWrapperArgs = [ ''--prefix PATH : /path/to/bin'' ];
+}
+```
+
+The entries are passed as arguments to [wrapProgram](#fun-wrapProgram).
+
+Set `dontWrapQtApps` to stop applications from being wrapped automatically.
+Wrap programs manually with `wrapQtApp`, using the syntax of
+[wrapProgram](#fun-wrapProgram):
+
+```nix
+{ stdenv, lib, wrapQtAppsHook }:
+
+stdenv.mkDerivation {
+  # ...
+  nativeBuildInputs = [ wrapQtAppsHook ];
+  dontWrapQtApps = true;
+  preFixup = ''
+      wrapQtApp "$out/bin/myapp" --prefix PATH : /path/to/bin
+  '';
+}
+```
+
+::: {.note}
+`wrapQtAppsHook` ignores files that are non-ELF executables.
+This means that scripts won't be automatically wrapped so you'll need to manually wrap them as previously mentioned.
+An example of when you'd always need to do this is with Python applications that use PyQt.
+:::
+
+## Adding a library to Nixpkgs {#adding-a-library-to-nixpkgs}
+
+Add Qt libraries to `qt5-packages.nix` to make them available for every
+supported Qt version.
+
+### Example adding a Qt library {#qt-library-all-packages-nix}
+
+The following represents the contents of `qt5-packages.nix`.
+
+```nix
+{
+  # ...
+
+  mylib = callPackage ../path/to/mylib {};
+
+  # ...
+}
+```
+
+Libraries are built with every available version of Qt.
+Use the `meta.broken` attribute to disable the package for unsupported Qt versions:
+
+```nix
+{ stdenv, lib, qtbase }:
+
+stdenv.mkDerivation {
+  # ...
+  # Disable this library with Qt < 5.9.0
+  meta.broken = lib.versionOlder qtbase.version "5.9.0";
+}
+```
+
+## Adding an application to Nixpkgs {#adding-an-application-to-nixpkgs}
+
+Add Qt applications to `qt5-packages.nix`. Add an alias to `all-packages.nix`
+to select the Qt 5 version used for the application.
+
+### Example adding a Qt application {#qt-application-all-packages-nix}
+
+The following represents the contents of `qt5-packages.nix`.
+
+```nix
+{
+  # ...
+
+  myapp = callPackage ../path/to/myapp {};
+
+  # ...
+}
+```
+
+The following represents the contents of `all-packages.nix`.
+
+```nix
+{
+  # ...
+
+  myapp = libsForQt5.myapp;
+
+  # ...
+}
+```

doc/languages-frameworks/r.section.md

@@ -0,0 +1,127 @@
+# R {#r}
+
+## Installation {#installation}
+
+Define an environment for R that contains all the libraries that you'd like to
+use by adding the following snippet to your $HOME/.config/nixpkgs/config.nix file:
+
+```nix
+{
+    packageOverrides = super: let self = super.pkgs; in
+    {
+
+        rEnv = super.rWrapper.override {
+            packages = with self.rPackages; [
+                devtools
+                ggplot2
+                reshape2
+                yaml
+                optparse
+                ];
+        };
+    };
+}
+```
+
+Then you can use `nix-env -f "<nixpkgs>" -iA rEnv` to install it into your user
+profile. The set of available libraries can be discovered by running the
+command `nix-env -f "<nixpkgs>" -qaP -A rPackages`. The first column from that
+output is the name that has to be passed to rWrapper in the code snipped above.
+
+However, if you'd like to add a file to your project source to make the
+environment available for other contributors, you can create a `default.nix`
+file like so:
+
+```nix
+with import <nixpkgs> {};
+{
+  myProject = stdenv.mkDerivation {
+    name = "myProject";
+    version = "1";
+    src = if lib.inNixShell then null else nix;
+
+    buildInputs = with rPackages; [
+      R
+      ggplot2
+      knitr
+    ];
+  };
+}
+```
+and then run `nix-shell .` to be dropped into a shell with those packages
+available.
+
+## RStudio {#rstudio}
+
+RStudio uses a standard set of packages and ignores any custom R
+environments or installed packages you may have.  To create a custom
+environment, see `rstudioWrapper`, which functions similarly to
+`rWrapper`:
+
+```nix
+{
+    packageOverrides = super: let self = super.pkgs; in
+    {
+
+        rstudioEnv = super.rstudioWrapper.override {
+            packages = with self.rPackages; [
+                dplyr
+                ggplot2
+                reshape2
+                ];
+        };
+    };
+}
+```
+
+Then like above, `nix-env -f "<nixpkgs>" -iA rstudioEnv` will install
+this into your user profile.
+
+Alternatively, you can create a self-contained `shell.nix` without the need to
+modify any configuration files:
+
+```nix
+{ pkgs ? import <nixpkgs> {}
+}:
+
+pkgs.rstudioWrapper.override {
+  packages = with pkgs.rPackages; [ dplyr ggplot2 reshape2 ];
+}
+
+```
+
+Executing `nix-shell` will then drop you into an environment equivalent to the
+one above. If you need additional packages just add them to the list and
+re-enter the shell.
+
+## Updating the package set {#updating-the-package-set}
+
+There is a script and associated environment for regenerating the package
+sets and synchronising the rPackages tree to the current CRAN and matching
+BIOC release. These scripts are found in the `pkgs/development/r-modules`
+directory and executed as follows:
+
+```bash
+nix-shell generate-shell.nix
+
+Rscript generate-r-packages.R cran  > cran-packages.nix.new
+mv cran-packages.nix.new cran-packages.nix
+
+Rscript generate-r-packages.R bioc  > bioc-packages.nix.new
+mv bioc-packages.nix.new bioc-packages.nix
+
+Rscript generate-r-packages.R bioc-annotation > bioc-annotation-packages.nix.new
+mv bioc-annotation-packages.nix.new bioc-annotation-packages.nix
+
+Rscript generate-r-packages.R bioc-experiment > bioc-experiment-packages.nix.new
+mv bioc-experiment-packages.nix.new bioc-experiment-packages.nix
+```
+
+`generate-r-packages.R <repo>` reads  `<repo>-packages.nix`, therefore
+the renaming.
+
+Some packages require overrides to specify external dependencies or other
+patches and special requirements. These overrides are specified in the
+`pkgs/development/r-modules/default.nix` file. As the `*-packages.nix`
+contents are automatically generated it should not be edited and broken
+builds should be addressed using overrides.

doc/languages-frameworks/ruby.section.md

@@ -0,0 +1,283 @@
+# Ruby {#sec-language-ruby}
+
+## Using Ruby {#using-ruby}
+
+Several versions of Ruby interpreters are available on Nix, as well as over 250 gems and many applications written in Ruby. The attribute `ruby` refers to the default Ruby interpreter, which is currently MRI 2.6. It's also possible to refer to specific versions, e.g. `ruby_2_y`, `jruby`, or `mruby`.
+
+In the Nixpkgs tree, Ruby packages can be found throughout, depending on what they do, and are called from the main package set. Ruby gems, however are separate sets, and there's one default set for each interpreter (currently MRI only).
+
+There are two main approaches for using Ruby with gems. One is to use a specifically locked `Gemfile` for an application that has very strict dependencies. The other is to depend on the common gems, which we'll explain further down, and rely on them being updated regularly.
+
+The interpreters have common attributes, namely `gems`, and `withPackages`. So you can refer to `ruby.gems.nokogiri`, or `ruby_2_7.gems.nokogiri` to get the Nokogiri gem already compiled and ready to use.
+
+Since not all gems have executables like `nokogiri`, it's usually more convenient to use the `withPackages` function like this: `ruby.withPackages (p: with p; [ nokogiri ])`. This will also make sure that the Ruby in your environment will be able to find the gem and it can be used in your Ruby code (for example via `ruby` or `irb` executables) via `require "nokogiri"` as usual.
+
+### Temporary Ruby environment with `nix-shell` {#temporary-ruby-environment-with-nix-shell}
+
+Rather than having a single Ruby environment shared by all Ruby development projects on a system, Nix allows you to create separate environments per project. `nix-shell` gives you the possibility to temporarily load another environment akin to a combined `chruby` or `rvm` and `bundle exec`.
+
+There are two methods for loading a shell with Ruby packages. The first and recommended method is to create an environment with `ruby.withPackages` and load that.
+
+```ShellSession
+$ nix-shell -p "ruby.withPackages (ps: with ps; [ nokogiri pry ])"
+```
+
+The other method, which is not recommended, is to create an environment and list all the packages directly.
+
+```ShellSession
+$ nix-shell -p ruby.gems.nokogiri ruby.gems.pry
+```
+
+Again, it's possible to launch the interpreter from the shell. The Ruby interpreter has the attribute `gems` which contains all Ruby gems for that specific interpreter.
+
+#### Load Ruby environment from `.nix` expression {#load-ruby-environment-from-.nix-expression}
+
+As explained in the Nix manual, `nix-shell` can also load an expression from a `.nix` file. Say we want to have Ruby 2.6, `nokogori`, and `pry`. Consider a `shell.nix` file with:
+
+```nix
+with import <nixpkgs> {};
+ruby.withPackages (ps: with ps; [ nokogiri pry ])
+```
+
+What's happening here?
+
+1. We begin with importing the Nix Packages collections. `import <nixpkgs>` imports the `<nixpkgs>` function, `{}` calls it and the `with` statement brings all attributes of `nixpkgs` in the local scope. These attributes form the main package set.
+2. Then we create a Ruby environment with the `withPackages` function.
+3. The `withPackages` function expects us to provide a function as an argument that takes the set of all ruby gems and returns a list of packages to include in the environment. Here, we select the packages `nokogiri` and `pry` from the package set.
+
+#### Execute command with `--run` {#execute-command-with---run}
+
+A convenient flag for `nix-shell` is `--run`. It executes a command in the `nix-shell`. We can e.g. directly open a `pry` REPL:
+
+```ShellSession
+$ nix-shell -p "ruby.withPackages (ps: with ps; [ nokogiri pry ])" --run "pry"
+```
+
+Or immediately require `nokogiri` in pry:
+
+```ShellSession
+$ nix-shell -p "ruby.withPackages (ps: with ps; [ nokogiri pry ])" --run "pry -rnokogiri"
+```
+
+Or run a script using this environment:
+
+```ShellSession
+$ nix-shell -p "ruby.withPackages (ps: with ps; [ nokogiri pry ])" --run "ruby example.rb"
+```
+
+#### Using `nix-shell` as shebang {#using-nix-shell-as-shebang}
+
+In fact, for the last case, there is a more convenient method. You can add a [shebang](<https://en.wikipedia.org/wiki/Shebang_(Unix)>) to your script specifying which dependencies `nix-shell` needs. With the following shebang, you can just execute `./example.rb`, and it will run with all dependencies.
+
+```ruby
+#! /usr/bin/env nix-shell
+#! nix-shell -i ruby -p "ruby.withPackages (ps: with ps; [ nokogiri rest-client ])"
+
+require 'nokogiri'
+require 'rest-client'
+
+body = RestClient.get('http://example.com').body
+puts Nokogiri::HTML(body).at('h1').text
+```
+
+## Developing with Ruby {#developing-with-ruby}
+
+### Using an existing Gemfile {#using-an-existing-gemfile}
+
+In most cases, you'll already have a `Gemfile.lock` listing all your dependencies. This can be used to generate a `gemset.nix` which is used to fetch the gems and combine them into a single environment. The reason why you need to have a separate file for this, is that Nix requires you to have a checksum for each input to your build. Since the `Gemfile.lock` that `bundler` generates doesn't provide us with checksums, we have to first download each gem, calculate its SHA256, and store it in this separate file.
+
+So the steps from having just a `Gemfile` to a `gemset.nix` are:
+
+```ShellSession
+$ bundle lock
+$ bundix
+```
+
+If you already have a `Gemfile.lock`, you can simply run `bundix` and it will work the same.
+
+To update the gems in your `Gemfile.lock`, you may use the `bundix -l` flag, which will create a new `Gemfile.lock` in case the `Gemfile` has a more recent time of modification.
+
+Once the `gemset.nix` is generated, it can be used in a `bundlerEnv` derivation. Here is an example you could use for your `shell.nix`:
+
+```nix
+# ...
+let
+  gems = bundlerEnv {
+    name = "gems-for-some-project";
+    gemdir = ./.;
+  };
+in mkShell { packages = [ gems gems.wrappedRuby ]; }
+```
+
+With this file in your directory, you can run `nix-shell` to build and use the gems. The important parts here are `bundlerEnv` and `wrappedRuby`.
+
+The `bundlerEnv` is a wrapper over all the gems in your gemset. This means that all the `/lib` and `/bin` directories will be available, and the executables of all gems (even of indirect dependencies) will end up in your `$PATH`. The `wrappedRuby` provides you with all executables that come with Ruby itself, but wrapped so they can easily find the gems in your gemset.
+
+One common issue that you might have is that you have Ruby 2.6, but also `bundler` in your gemset. That leads to a conflict for `/bin/bundle` and `/bin/bundler`. You can resolve this by wrapping either your Ruby or your gems in a `lowPrio` call. So in order to give the `bundler` from your gemset priority, it would be used like this:
+
+```nix
+# ...
+mkShell { buildInputs = [ gems (lowPrio gems.wrappedRuby) ]; }
+```
+
+### Gem-specific configurations and workarounds {#gem-specific-configurations-and-workarounds}
+
+In some cases, especially if the gem has native extensions, you might need to modify the way the gem is built.
+
+This is done via a common configuration file that includes all of the workarounds for each gem.
+
+This file lives at `/pkgs/development/ruby-modules/gem-config/default.nix`, since it already contains a lot of entries, it should be pretty easy to add the modifications you need for your needs.
+
+In the meanwhile, or if the modification is for a private gem, you can also add the configuration to only your own environment.
+
+Two places that allow this modification are the `ruby` derivation, or `bundlerEnv`.
+
+Here's the `ruby` one:
+
+```nix
+{ pg_version ? "10", pkgs ? import <nixpkgs> { } }:
+let
+  myRuby = pkgs.ruby.override {
+    defaultGemConfig = pkgs.defaultGemConfig // {
+      pg = attrs: {
+        buildFlags =
+        [ "--with-pg-config=${pkgs."postgresql_${pg_version}"}/bin/pg_config" ];
+      };
+    };
+  };
+in myRuby.withPackages (ps: with ps; [ pg ])
+```
+
+And an example with `bundlerEnv`:
+
+```nix
+{ pg_version ? "10", pkgs ? import <nixpkgs> { } }:
+let
+  gems = pkgs.bundlerEnv {
+    name = "gems-for-some-project";
+    gemdir = ./.;
+    gemConfig = pkgs.defaultGemConfig // {
+      pg = attrs: {
+        buildFlags =
+        [ "--with-pg-config=${pkgs."postgresql_${pg_version}"}/bin/pg_config" ];
+      };
+    };
+  };
+in mkShell { buildInputs = [ gems gems.wrappedRuby ]; }
+```
+
+And finally via overlays:
+
+```nix
+{ pg_version ? "10" }:
+let
+  pkgs = import <nixpkgs> {
+    overlays = [
+      (self: super: {
+        defaultGemConfig = super.defaultGemConfig // {
+          pg = attrs: {
+            buildFlags = [
+              "--with-pg-config=${
+                pkgs."postgresql_${pg_version}"
+              }/bin/pg_config"
+            ];
+          };
+        };
+      })
+    ];
+  };
+in pkgs.ruby.withPackages (ps: with ps; [ pg ])
+```
+
+Then we can get whichever postgresql version we desire and the `pg` gem will always reference it correctly:
+
+```ShellSession
+$ nix-shell --argstr pg_version 9_4 --run 'ruby -rpg -e "puts PG.library_version"'
+90421
+
+$ nix-shell --run 'ruby -rpg -e "puts PG.library_version"'
+100007
+```
+
+Of course for this use-case one could also use overlays since the configuration for `pg` depends on the `postgresql` alias, but for demonstration purposes this has to suffice.
+
+### Platform-specific gems
+
+Right now, bundix has some issues with pre-built, platform-specific gems: [bundix PR #68](https://github.com/nix-community/bundix/pull/68).
+Until this is solved, you can tell bundler to not use platform-specific gems and instead build them from source each time:
+- globally (will be set in `~/.config/.bundle/config`):
+```shell
+$ bundle config set force_ruby_platform true
+```
+- locally (will be set in `<project-root>/.bundle/config`):
+```shell
+$ bundle config set --local force_ruby_platform true
+```
+
+### Adding a gem to the default gemset {#adding-a-gem-to-the-default-gemset}
+
+Now that you know how to get a working Ruby environment with Nix, it's time to go forward and start actually developing with Ruby. We will first have a look at how Ruby gems are packaged on Nix. Then, we will look at how you can use development mode with your code.
+
+All gems in the standard set are automatically generated from a single `Gemfile`. The dependency resolution is done with `bundler` and makes it more likely that all gems are compatible to each other.
+
+In order to add a new gem to nixpkgs, you can put it into the `/pkgs/development/ruby-modules/with-packages/Gemfile` and run `./maintainers/scripts/update-ruby-packages`.
+
+To test that it works, you can then try using the gem with:
+
+```shell
+NIX_PATH=nixpkgs=$PWD nix-shell -p "ruby.withPackages (ps: with ps; [ name-of-your-gem ])"
+```
+
+### Packaging applications {#packaging-applications}
+
+A common task is to add a ruby executable to nixpkgs, popular examples would be `chef`, `jekyll`, or `sass`. A good way to do that is to use the `bundlerApp` function, that allows you to make a package that only exposes the listed executables, otherwise the package may cause conflicts through common paths like `bin/rake` or `bin/bundler` that aren't meant to be used.
+
+The absolute easiest way to do that is to write a `Gemfile` along these lines:
+
+```ruby
+source 'https://rubygems.org' do
+  gem 'mdl'
+end
+```
+
+If you want to package a specific version, you can use the standard Gemfile syntax for that, e.g. `gem 'mdl', '0.5.0'`, but if you want the latest stable version anyway, it's easier to update by simply running the `bundle lock` and `bundix` steps again.
+
+Now you can also make a `default.nix` that looks like this:
+
+```nix
+{ bundlerApp }:
+
+bundlerApp {
+  pname = "mdl";
+  gemdir = ./.;
+  exes = [ "mdl" ];
+}
+```
+
+All that's left to do is to generate the corresponding `Gemfile.lock` and `gemset.nix` as described above in the `Using an existing Gemfile` section.
+
+#### Packaging executables that require wrapping {#packaging-executables-that-require-wrapping}
+
+Sometimes your app will depend on other executables at runtime, and tries to find it through the `PATH` environment variable.
+
+In this case, you can provide a `postBuild` hook to `bundlerApp` that wraps the gem in another script that prefixes the `PATH`.
+
+Of course you could also make a custom `gemConfig` if you know exactly how to patch it, but it's usually much easier to maintain with a simple wrapper so the patch doesn't have to be adjusted for each version.
+
+Here's another example:
+
+```nix
+{ lib, bundlerApp, makeWrapper, git, gnutar, gzip }:
+
+bundlerApp {
+  pname = "r10k";
+  gemdir = ./.;
+  exes = [ "r10k" ];
+
+  buildInputs = [ makeWrapper ];
+
+  postBuild = ''
+    wrapProgram $out/bin/r10k --prefix PATH : ${lib.makeBinPath [ git gnutar gzip ]}
+  '';
+}
+```

doc/languages-frameworks/texlive.section.md

@@ -0,0 +1,129 @@
+# TeX Live {#sec-language-texlive}
+
+Since release 15.09 there is a new TeX Live packaging that lives entirely under attribute `texlive`.
+
+## User's guide {#sec-language-texlive-user-guide}
+
+- For basic usage just pull `texlive.combined.scheme-basic` for an environment with basic LaTeX support.
+
+- It typically won't work to use separately installed packages together. Instead, you can build a custom set of packages like this. Most CTAN packages should be available:
+
+  ```nix
+  texlive.combine {
+    inherit (texlive) scheme-small collection-langkorean algorithms cm-super;
+  }
+  ```
+
+- There are all the schemes, collections and a few thousand packages, as defined upstream (perhaps with tiny differences).
+
+- By default you only get executables and files needed during runtime, and a little documentation for the core packages. To change that, you need to add `pkgFilter` function to `combine`.
+
+  ```nix
+  texlive.combine {
+    # inherit (texlive) whatever-you-want;
+    pkgFilter = pkg:
+      pkg.tlType == "run" || pkg.tlType == "bin" || pkg.pname == "cm-super";
+    # elem tlType [ "run" "bin" "doc" "source" ]
+    # there are also other attributes: version, name
+  }
+  ```
+
+- You can list packages e.g. by `nix repl`.
+
+  ```ShellSession
+  $ nix repl
+  nix-repl> :l <nixpkgs>
+  nix-repl> texlive.collection-[TAB]
+  ```
+
+- Note that the wrapper assumes that the result has a chance to be useful. For example, the core executables should be present, as well as some core data files. The supported way of ensuring this is by including some scheme, for example `scheme-basic`, into the combination.
+
+## Custom packages {#sec-language-texlive-custom-packages}
+
+
+You may find that you need to use an external TeX package. A derivation for such package has to provide contents of the "texmf" directory in its output and provide the `tlType` attribute. Here is a (very verbose) example:
+
+```nix
+with import <nixpkgs> {};
+
+let
+  foiltex_run = stdenvNoCC.mkDerivation {
+    pname = "latex-foiltex";
+    version = "2.1.4b";
+    passthru.tlType = "run";
+
+    srcs = [
+      (fetchurl {
+        url = "http://mirrors.ctan.org/macros/latex/contrib/foiltex/foiltex.dtx";
+        sha256 = "07frz0krpz7kkcwlayrwrj2a2pixmv0icbngyw92srp9fp23cqpz";
+      })
+      (fetchurl {
+        url = "http://mirrors.ctan.org/macros/latex/contrib/foiltex/foiltex.ins";
+        sha256 = "09wkyidxk3n3zvqxfs61wlypmbhi1pxmjdi1kns9n2ky8ykbff99";
+      })
+    ];
+
+    unpackPhase = ''
+      runHook preUnpack
+
+      for _src in $srcs; do
+        cp "$_src" $(stripHash "$_src")
+      done
+
+      runHook postUnpack
+    '';
+
+    nativeBuildInputs = [ texlive.combined.scheme-small ];
+
+    dontConfigure = true;
+
+    buildPhase = ''
+      runHook preBuild
+
+      # Generate the style files
+      latex foiltex.ins
+
+      runHook postBuild
+    '';
+
+    installPhase = ''
+      runHook preInstall
+
+      path="$out/tex/latex/foiltex"
+      mkdir -p "$path"
+      cp *.{cls,def,clo} "$path/"
+
+      runHook postInstall
+    '';
+
+    meta = with lib; {
+      description = "A LaTeX2e class for overhead transparencies";
+      license = licenses.unfreeRedistributable;
+      maintainers = with maintainers; [ veprbl ];
+      platforms = platforms.all;
+    };
+  };
+  foiltex = { pkgs = [ foiltex_run ]; };
+
+  latex_with_foiltex = texlive.combine {
+    inherit (texlive) scheme-small;
+    inherit foiltex;
+  };
+in
+  runCommand "test.pdf" {
+    nativeBuildInputs = [ latex_with_foiltex ];
+  } ''
+cat >test.tex <<EOF
+\documentclass{foils}
+
+\title{Presentation title}
+\date{}
+
+\begin{document}
+\maketitle
+\end{document}
+EOF
+  pdflatex test.tex
+  cp test.pdf $out
+''
+```

doc/languages-frameworks/titanium.section.md

@@ -0,0 +1,110 @@
+# Titanium {#titanium}
+
+The Nixpkgs repository contains facilities to deploy a variety of versions of
+the [Titanium SDK](https://www.appcelerator.com) versions, a cross-platform
+mobile app development framework using JavaScript as an implementation language,
+and includes a function abstraction making it possible to build Titanium
+applications for Android and iOS devices from source code.
+
+Not all Titanium features supported -- currently, it can only be used to build
+Android and iOS apps.
+
+## Building a Titanium app {#building-a-titanium-app}
+
+We can build a Titanium app from source for Android or iOS and for debugging or
+release purposes by invoking the `titaniumenv.buildApp {}` function:
+
+```nix
+titaniumenv.buildApp {
+  name = "myapp";
+  src = ./myappsource;
+
+  preBuild = "";
+  target = "android"; # or 'iphone'
+  tiVersion = "7.1.0.GA";
+  release = true;
+
+  androidsdkArgs = {
+    platformVersions = [ "25" "26" ];
+  };
+  androidKeyStore = ./keystore;
+  androidKeyAlias = "myfirstapp";
+  androidKeyStorePassword = "secret";
+
+  xcodeBaseDir = "/Applications/Xcode.app";
+  xcodewrapperArgs = {
+    version = "9.3";
+  };
+  iosMobileProvisioningProfile = ./myprovisioning.profile;
+  iosCertificateName = "My Company";
+  iosCertificate = ./mycertificate.p12;
+  iosCertificatePassword = "secret";
+  iosVersion = "11.3";
+  iosBuildStore = false;
+
+  enableWirelessDistribution = true;
+  installURL = "/installipa.php";
+}
+```
+
+The `titaniumenv.buildApp {}` function takes the following parameters:
+
+* The `name` parameter refers to the name in the Nix store.
+* The `src` parameter refers to the source code location of the app that needs
+  to be built.
+* `preRebuild` contains optional build instructions that are carried out before
+  the build starts.
+* `target` indicates for which device the app must be built. Currently only
+  'android' and 'iphone' (for iOS) are supported.
+* `tiVersion` can be used to optionally override the requested Titanium version
+  in `tiapp.xml`. If not specified, it will use the version in `tiapp.xml`.
+* `release` should be set to true when building an app for submission to the
+  Google Playstore or Apple Appstore. Otherwise, it should be false.
+
+When the `target` has been set to `android`, we can configure the following
+parameters:
+
+* The `androidSdkArgs` parameter refers to an attribute set that propagates all
+  parameters to the `androidenv.composeAndroidPackages {}` function. This can
+  be used to install all relevant Android plugins that may be needed to perform
+  the Android build. If no parameters are given, it will deploy the platform
+  SDKs for API-levels 25 and 26 by default.
+
+When the `release` parameter has been set to true, you need to provide
+parameters to sign the app:
+
+* `androidKeyStore` is the path to the keystore file
+* `androidKeyAlias` is the key alias
+* `androidKeyStorePassword` refers to the password to open the keystore file.
+
+When the `target` has been set to `iphone`, we can configure the following
+parameters:
+
+* The `xcodeBaseDir` parameter refers to the location where Xcode has been
+  installed. When none value is given, the above value is the default.
+* The `xcodewrapperArgs` parameter passes arbitrary parameters to the
+  `xcodeenv.composeXcodeWrapper {}` function. This can, for example, be used
+  to adjust the default version of Xcode.
+
+When `release` has been set to true, you also need to provide the following
+parameters:
+
+* `iosMobileProvisioningProfile` refers to a mobile provisioning profile needed
+  for signing.
+* `iosCertificateName` refers to the company name in the P12 certificate.
+* `iosCertificate` refers to the path to the P12 file.
+* `iosCertificatePassword` contains the password to open the P12 file.
+* `iosVersion` refers to the iOS SDK version to use. It defaults to the latest
+  version.
+* `iosBuildStore` should be set to `true` when building for the Apple Appstore
+  submission. For enterprise or ad-hoc builds it should be set to `false`.
+
+When `enableWirelessDistribution` has been enabled, you must also provide the
+path of the PHP script (`installURL`) (that is included with the iOS build
+environment) to enable wireless ad-hoc installations.
+
+## Emulating or simulating the app {#emulating-or-simulating-the-app}
+
+It is also possible to simulate the correspond iOS simulator build by using
+`xcodeenv.simulateApp {}` and emulate an Android APK by using
+`androidenv.emulateApp {}`.

doc/languages-frameworks/vim.section.md

@@ -0,0 +1,351 @@
+# Vim {#vim}
+
+Both Neovim and Vim can be configured to include your favorite plugins
+and additional libraries.
+
+Loading can be deferred; see examples.
+
+At the moment we support three different methods for managing plugins:
+
+- Vim packages (*recommend*)
+- VAM (=vim-addon-manager)
+- Pathogen
+- vim-plug
+
+## Custom configuration {#custom-configuration}
+
+Adding custom .vimrc lines can be done using the following code:
+
+```nix
+vim_configurable.customize {
+  # `name` optionally specifies the name of the executable and package
+  name = "vim-with-plugins";
+
+  vimrcConfig.customRC = ''
+    set hidden
+  '';
+}
+```
+
+This configuration is used when Vim is invoked with the command specified as name, in this case `vim-with-plugins`.
+You can also omit `name` to customize Vim itself. See the
+[definition of `vimUtils.makeCustomizable`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/vim/plugins/vim-utils.nix#L408)
+for all supported options.
+
+For Neovim the `configure` argument can be overridden to achieve the same:
+
+```nix
+neovim.override {
+  configure = {
+    customRC = ''
+      # here your custom configuration goes!
+    '';
+  };
+}
+```
+
+If you want to use `neovim-qt` as a graphical editor, you can configure it by overriding Neovim in an overlay
+or passing it an overridden Neovimn:
+
+```nix
+neovim-qt.override {
+  neovim = neovim.override {
+    configure = {
+      customRC = ''
+        # your custom configuration
+      '';
+    };
+  };
+}
+```
+
+## Managing plugins with Vim packages {#managing-plugins-with-vim-packages}
+
+To store you plugins in Vim packages (the native Vim plugin manager, see `:help packages`) the following example can be used:
+
+```nix
+vim_configurable.customize {
+  vimrcConfig.packages.myVimPackage = with pkgs.vimPlugins; {
+    # loaded on launch
+    start = [ youcompleteme fugitive ];
+    # manually loadable by calling `:packadd $plugin-name`
+    # however, if a Vim plugin has a dependency that is not explicitly listed in
+    # opt that dependency will always be added to start to avoid confusion.
+    opt = [ phpCompletion elm-vim ];
+    # To automatically load a plugin when opening a filetype, add vimrc lines like:
+    # autocmd FileType php :packadd phpCompletion
+  };
+}
+```
+
+`myVimPackage` is an arbitrary name for the generated package. You can choose any name you like.
+For Neovim the syntax is:
+
+```nix
+neovim.override {
+  configure = {
+    customRC = ''
+      # here your custom configuration goes!
+    '';
+    packages.myVimPackage = with pkgs.vimPlugins; {
+      # see examples below how to use custom packages
+      start = [ ];
+      # If a Vim plugin has a dependency that is not explicitly listed in
+      # opt that dependency will always be added to start to avoid confusion.
+      opt = [ ];
+    };
+  };
+}
+```
+
+The resulting package can be added to `packageOverrides` in `~/.nixpkgs/config.nix` to make it installable:
+
+```nix
+{
+  packageOverrides = pkgs: with pkgs; {
+    myVim = vim_configurable.customize {
+      # `name` specifies the name of the executable and package
+      name = "vim-with-plugins";
+      # add here code from the example section
+    };
+    myNeovim = neovim.override {
+      configure = {
+      # add here code from the example section
+      };
+    };
+  };
+}
+```
+
+After that you can install your special grafted `myVim` or `myNeovim` packages.
+
+### What if your favourite Vim plugin isn’t already packaged? {#what-if-your-favourite-vim-plugin-isnt-already-packaged}
+
+If one of your favourite plugins isn't packaged, you can package it yourself:
+
+```nix
+{ config, pkgs, ... }:
+
+let
+  easygrep = pkgs.vimUtils.buildVimPlugin {
+    name = "vim-easygrep";
+    src = pkgs.fetchFromGitHub {
+      owner = "dkprice";
+      repo = "vim-easygrep";
+      rev = "d0c36a77cc63c22648e792796b1815b44164653a";
+      sha256 = "0y2p5mz0d5fhg6n68lhfhl8p4mlwkb82q337c22djs4w5zyzggbc";
+    };
+  };
+in
+{
+  environment.systemPackages = [
+    (
+      pkgs.neovim.override {
+        configure = {
+          packages.myPlugins = with pkgs.vimPlugins; {
+          start = [
+            vim-go # already packaged plugin
+            easygrep # custom package
+          ];
+          opt = [];
+        };
+        # ...
+      };
+     }
+    )
+  ];
+}
+```
+
+### Specificities for some plugins
+#### Tree sitter
+
+By default `nvim-treesitter` encourages you to download, compile and install
+the required tree-sitter grammars at run time with `:TSInstall`. This works
+poorly on NixOS.  Instead, to install the `nvim-treesitter` plugins with a set
+of precompiled grammars, you can use `nvim-treesitter.withPlugins` function:
+
+```nix
+(pkgs.neovim.override {
+  configure = {
+    packages.myPlugins = with pkgs.vimPlugins; {
+      start = [
+        (nvim-treesitter.withPlugins (
+          plugins: with plugins; [
+            tree-sitter-nix
+            tree-sitter-python
+          ]
+        ))
+      ];
+    };
+  };
+})
+```
+
+To enable all grammars packaged in nixpkgs, use `(pkgs.vimPlugins.nvim-treesitter.withPlugins (plugins: pkgs.tree-sitter.allGrammars))`.
+
+## Managing plugins with vim-plug {#managing-plugins-with-vim-plug}
+
+To use [vim-plug](https://github.com/junegunn/vim-plug) to manage your Vim
+plugins the following example can be used:
+
+```nix
+vim_configurable.customize {
+  vimrcConfig.packages.myVimPackage = with pkgs.vimPlugins; {
+    # loaded on launch
+    plug.plugins = [ youcompleteme fugitive phpCompletion elm-vim ];
+  };
+}
+```
+
+For Neovim the syntax is:
+
+```nix
+neovim.override {
+  configure = {
+    customRC = ''
+      # here your custom configuration goes!
+    '';
+    plug.plugins = with pkgs.vimPlugins; [
+      vim-go
+    ];
+  };
+}
+```
+
+## Managing plugins with VAM {#managing-plugins-with-vam}
+
+### Handling dependencies of Vim plugins {#handling-dependencies-of-vim-plugins}
+
+VAM introduced .json files supporting dependencies without versioning
+assuming that "using latest version" is ok most of the time.
+
+### Example {#example}
+
+First create a vim-scripts file having one plugin name per line. Example:
+
+```vim
+"tlib"
+{'name': 'vim-addon-sql'}
+{'filetype_regex': '\%(vim)$', 'names': ['reload', 'vim-dev-plugin']}
+```
+
+Such vim-scripts file can be read by VAM as well like this:
+
+```vim
+call vam#Scripts(expand('~/.vim-scripts'), {})
+```
+
+Create a default.nix file:
+
+```nix
+{ nixpkgs ? import <nixpkgs> {}, compiler ? "ghc7102" }:
+nixpkgs.vim_configurable.customize { name = "vim"; vimrcConfig.vam.pluginDictionaries = [ "vim-addon-vim2nix" ]; }
+```
+
+Create a generate.vim file:
+
+```vim
+ActivateAddons vim-addon-vim2nix
+let vim_scripts = "vim-scripts"
+call nix#ExportPluginsForNix({
+\  'path_to_nixpkgs': eval('{"'.substitute(substitute(substitute($NIX_PATH, ':', ',', 'g'), '=',':', 'g'), '\([:,]\)', '"\1"',"g").'"}')["nixpkgs"],
+\  'cache_file': '/tmp/vim2nix-cache',
+\  'try_catch': 0,
+\  'plugin_dictionaries': ["vim-addon-manager"]+map(readfile(vim_scripts), 'eval(v:val)')
+\ })
+```
+
+Then run
+
+```bash
+nix-shell -p vimUtils.vim_with_vim2nix --command "vim -c 'source generate.vim'"
+```
+
+You should get a Vim buffer with the nix derivations (output1) and vam.pluginDictionaries (output2).
+You can add your Vim to your system's configuration file like this and start it by "vim-my":
+
+```nix
+my-vim =
+  let plugins = let inherit (vimUtils) buildVimPluginFrom2Nix; in {
+    copy paste output1 here
+  }; in vim_configurable.customize {
+    name = "vim-my";
+
+    vimrcConfig.vam.knownPlugins = plugins; # optional
+    vimrcConfig.vam.pluginDictionaries = [
+       copy paste output2 here
+    ];
+
+    # Pathogen would be
+    # vimrcConfig.pathogen.knownPlugins = plugins; # plugins
+    # vimrcConfig.pathogen.pluginNames = ["tlib"];
+  };
+```
+
+Sample output1:
+
+```nix
+"reload" = buildVimPluginFrom2Nix { # created by nix#NixDerivation
+  name = "reload";
+  src = fetchgit {
+    url = "https://github.com/xolox/vim-reload";
+    rev = "0a601a668727f5b675cb1ddc19f6861f3f7ab9e1";
+    sha256 = "0vb832l9yxj919f5hfg6qj6bn9ni57gnjd3bj7zpq7d4iv2s4wdh";
+  };
+  dependencies = ["nim-misc"];
+
+};
+[...]
+```
+
+Sample output2:
+
+```nix
+[
+  ''vim-addon-manager''
+  ''tlib''
+  { "name" = ''vim-addon-sql''; }
+  { "filetype_regex" = ''\%(vim)$$''; "names" = [ ''reload'' ''vim-dev-plugin'' ]; }
+]
+```
+
+## Adding new plugins to nixpkgs {#adding-new-plugins-to-nixpkgs}
+
+Nix expressions for Vim plugins are stored in [pkgs/applications/editors/vim/plugins](https://github.com/NixOS/nixpkgs/tree/master/pkgs/applications/editors/vim/plugins). For the vast majority of plugins, Nix expressions are automatically generated by running [`./update.py`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/vim/plugins/update.py). This creates a [generated.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/vim/plugins/generated.nix) file based on the plugins listed in [vim-plugin-names](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/vim/plugins/vim-plugin-names). Plugins are listed in alphabetical order in `vim-plugin-names` using the format `[github username]/[repository]@[gitref]`. For example https://github.com/scrooloose/nerdtree becomes `scrooloose/nerdtree`.
+
+Some plugins require overrides in order to function properly. Overrides are placed in [overrides.nix](https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/editors/vim/plugins/overrides.nix). Overrides are most often required when a plugin requires some dependencies, or extra steps are required during the build process. For example `deoplete-fish` requires both `deoplete-nvim` and `vim-fish`, and so the following override was added:
+
+```nix
+deoplete-fish = super.deoplete-fish.overrideAttrs(old: {
+  dependencies = with super; [ deoplete-nvim vim-fish ];
+});
+```
+
+Sometimes plugins require an override that must be changed when the plugin is updated. This can cause issues when Vim plugins are auto-updated but the associated override isn't updated. For these plugins, the override should be written so that it specifies all information required to install the plugin, and running `./update.py` doesn't change the derivation for the plugin. Manually updating the override is required to update these types of plugins. An example of such a plugin is `LanguageClient-neovim`.
+
+To add a new plugin, run `./update.py --add "[owner]/[name]"`. **NOTE**: This script automatically commits to your git repository. Be sure to check out a fresh branch before running.
+
+Finally, there are some plugins that are also packaged in nodePackages because they have Javascript-related build steps, such as running webpack. Those plugins are not listed in `vim-plugin-names` or managed by `update.py` at all, and are included separately in `overrides.nix`. Currently, all these plugins are related to the `coc.nvim` ecosystem of Language Server Protocol integration with vim/neovim.
+
+## Updating plugins in nixpkgs {#updating-plugins-in-nixpkgs}
+
+Run the update script with a GitHub API token that has at least `public_repo` access. Running the script without the token is likely to result in rate-limiting (429 errors). For steps on creating an API token, please refer to [GitHub's token documentation](https://docs.github.com/en/free-pro-team@latest/github/authenticating-to-github/creating-a-personal-access-token).
+
+```sh
+GITHUB_API_TOKEN=my_token ./pkgs/applications/editors/vim/plugins/update.py
+```
+
+Alternatively, set the number of processes to a lower count to avoid rate-limiting.
+
+```sh
+./pkgs/applications/editors/vim/plugins/update.py --proc 1
+```
+
+## Important repositories {#important-repositories}
+
+- [vim-pi](https://bitbucket.org/vimcommunity/vim-pi) is a plugin repository
+  from VAM plugin manager meant to be used by others as well used by
+
+- [vim2nix](https://github.com/MarcWeber/vim-addon-vim2nix) which generates the
+  .nix code

doc/manual.xml

@@ -0,0 +1,44 @@
+<book xmlns="http://docbook.org/ns/docbook"
+      xmlns:xi="http://www.w3.org/2001/XInclude">
+ <info>
+  <title>Nixpkgs Manual</title>
+  <subtitle>Version <xi:include href=".version" parse="text" />
+  </subtitle>
+ </info>
+ <xi:include href="preface.chapter.xml" />
+ <part>
+  <title>Using Nixpkgs</title>
+  <xi:include href="using/configuration.chapter.xml" />
+  <xi:include href="using/overlays.chapter.xml" />
+  <xi:include href="using/overrides.chapter.xml" />
+  <xi:include href="functions.xml" />
+ </part>
+ <part>
+  <title>Standard environment</title>
+  <xi:include href="stdenv/stdenv.chapter.xml" />
+  <xi:include href="stdenv/meta.chapter.xml" />
+  <xi:include href="stdenv/multiple-output.chapter.xml" />
+  <xi:include href="stdenv/cross-compilation.chapter.xml" />
+  <xi:include href="stdenv/platform-notes.chapter.xml" />
+ </part>
+ <part>
+  <title>Builders</title>
+  <xi:include href="builders/fetchers.chapter.xml" />
+  <xi:include href="builders/trivial-builders.chapter.xml" />
+  <xi:include href="builders/testers.chapter.xml" />
+  <xi:include href="builders/special.xml" />
+  <xi:include href="builders/images.xml" />
+  <xi:include href="hooks/index.xml" />
+  <xi:include href="languages-frameworks/index.xml" />
+  <xi:include href="builders/packages/index.xml" />
+ </part>
+ <part>
+  <title>Contributing to Nixpkgs</title>
+  <xi:include href="contributing/quick-start.chapter.xml" />
+  <xi:include href="contributing/coding-conventions.chapter.xml" />
+  <xi:include href="contributing/submitting-changes.chapter.xml" />
+  <xi:include href="contributing/vulnerability-roundup.chapter.xml" />
+  <xi:include href="contributing/reviewing-contributions.chapter.xml" />
+  <xi:include href="contributing/contributing-to-documentation.chapter.xml" />
+ </part>
+</book>