day 1 part 1

01a.lisp

@@ -0,0 +1,45 @@
+(require :uiop)
+
+(defun split-instruction (s)
+  (cons
+    (intern (subseq s 0 1))
+    (parse-integer (subseq s 1))))
+
+(defun turn-dial (dial instruction)
+  (let ((cons-instruction (split-instruction instruction)))
+    (let ((op (car cons-instruction))
+      (amount (cdr cons-instruction)))
+        (mod
+          (funcall
+            (cond
+              ((eql 'L op) #'-)
+              ((eql 'R op) #'+)
+              (t (error "unknown op")))
+            dial amount)
+          100)
+      )
+    ))
+
+;; (turn-dial 50 "L68")
+;; (turn-dial 82 "L30")
+;; (turn-dial 52 "R48")
+;; (turn-dial 0 "L5")
+;; (turn-dial 95 "R60")
+;; (turn-dial 55 "L55")
+;; (turn-dial 0 "L1")
+;; (turn-dial 99 "L99")
+;; (turn-dial 0 "R14")
+;; (turn-dial 14 "L82")
+
+(defun rec-dial-vm (accum dial lines)
+  (let ((instruction (pop lines)))
+    (if instruction
+      (let ((new-dial (turn-dial dial instruction)))
+        ;(format t "~A ~A -> ~A ~%" dial instruction new-dial)
+        (if (= new-dial 0)
+          (rec-dial-vm (+ 1 accum) new-dial lines)
+          (rec-dial-vm accum new-dial lines)))
+      accum)))
+
+(rec-dial-vm 0 50 (uiop:read-file-lines "01example.txt"))
+(rec-dial-vm 0 50 (uiop:read-file-lines "01data.txt"))