One-dimensional cellular automata: Difference between revisions

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@@ Line 2,373: / Line 2,373: @@
 bnd :: String -> Char
-bnd bs =
+bnd "_##" = '#'
+bnd "#_#" = '#'
-  case bs of
-    "_##" -> '#'
+bnd "##_" = '#'
-    "#_#" -> '#'
+bnd  _ = '_'
-    "##_" -> '#'
-    _ -> '_'
-donxt :: String -> String
+nxt :: String -> String
+nxt = unfoldr go . ('_' :) . (<> "_")
-donxt xs =
-  unfoldr
+  where
+    go [_, _] = Nothing
-    (\xs ->
-        case xs of
+    go xs = Just (bnd $ take 3 xs, drop 1 xs)
-          [_, _] -> Nothing
-          _ -> Just (bnd $ take 3 xs, drop 1 xs)) $
-  '_' : xs ++ "_"
 lahmahgaan :: String -> [String]
 lahmahgaan xs =
+  init . until ((==) . last <*> (last . init)) ((<>) <*> (return . nxt . last)) $
-  init .
+  [xs, nxt xs]
-  until ((==) . last <*> (last . init)) ((++) <*> (return . donxt . last)) $
-  [xs, donxt xs]
 main :: IO ()