apl: life Conway via 9-shift toroidal sum (+7 tests, 287/287)

2026-05-07 04:36:49 +00:00
parent ed0853f4a0
commit 20a61de693
6 changed files with 177 additions and 6 deletions
--- a/lib/apl/runtime.sx
+++ b/lib/apl/runtime.sx
@@ -824,6 +824,18 @@
              ((prime-mask (apl-eq (apl-scalar 2) divisor-counts)))
              (apl-compress prime-mask a))))))))

+(define
+  apl-life-step
+  (fn
+    (board)
+    (let
+      ((zero-board (apl-mul board (apl-scalar 0))))
+      (let
+        ((sum-board (reduce (fn (acc dr) (reduce (fn (acc2 dc) (apl-add acc2 (apl-rotate-first (apl-scalar dr) (apl-rotate (apl-scalar dc) board)))) acc (list -1 0 1))) zero-board (list -1 0 1))))
+        (apl-or
+          (apl-eq sum-board (apl-scalar 3))
+          (apl-and board (apl-eq sum-board (apl-scalar 4))))))))
+
 (define
  apl-reduce
  (fn