tasks a-s

Task/One-dimensional-cellular-automata/Retro/one-dimensional-cellular-automata.retro

@@ -0,0 +1,33 @@
+{{
+  : $, ( $- ) withLength [ @+ , ] times @ , ;
+  create this   ".###.##.#.#.#.#..#.." $,
+  create next   this getLength allot
+  create group  "..." $,
+  variable neighbours
+
+  : reset                  0 !neighbours ;
+  : hasNeighbour?          @ '# = [ neighbours ++ ] ifTrue ;
+  : countNeighboursOnEdge  '# = [ 1 ] [ 0 ] if !neighbours ;
+  : flip                   dup this + @ '# = [ '. ] [ '# ] if ;
+  : extract                dup this + 1- group 3 copy ;
+
+  : count
+    ( left   ) [  0 = ] [ @this        countNeighboursOnEdge ] when
+    ( right  ) [ 19 = ] [  this 19 + @ countNeighboursOnEdge ] when
+    ( middle ) reset extract group dup 2 + 2hasNeighbour? ;
+
+  : process
+    reset count @neighbours
+    [ 0 = ] [ drop dup next + '. swap !       ] when
+    [ 1 = ] [ drop dup this + @ over next + ! ] when
+    [ 2 = ] [ drop flip over next + !         ] when
+    drop ;
+
+  : generation
+    0 this getLength
+    [ process 1+ ] times drop
+    next this withLength copy ;
+---reveal---
+  : generations
+    cr 0 swap [ [ this swap "%d %s\n" puts ] sip generation 1+ ] times drop ;
+}}