September 2017 Update

Task/One-dimensional-cellular-automata/Prolog/one-dimensional-cellular-automata.pro

@@ -33,7 +33,28 @@ compute_next([1, 1, 1 | R], [0 | R1]) :-
 
 % the last four possibilies =>
 % we consider that there is à 0  after the end
-compute_next([0, 0], [0]).
+complang jq># The 1-d cellular automaton:
+def next:
+   # Conveniently, jq treats null as 0 when it comes to addition
+   # so there is no need to fiddle with the boundaries
+  . as $old
+  | reduce range(0; length) as $i
+    ([];
+     ($old[$i-1] + $old[$i+1]) as $s
+     | if   $s == 0 then .[$i] = 0
+       elif $s == 1 then .[$i] = (if $old[$i] == 1 then 1 else 0 end)
+       else              .[$i] = (if $old[$i] == 1 then 0 else 1 end)
+       end);
+
+
+# pretty-print an array:
+def pp: reduce .[] as $i (""; . + (if $i == 0 then " " else "*" end));
+
+# continue until quiescence:
+def go: recurse(. as $prev | next | if . == $prev then empty else . end) | pp;
+
+# Example:
+[0,1,1,1,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,0] | goute_next([0, 0], [0]).
 
 compute_next([1, 0], [0]).