June 2018 Update

Task/Multisplit/Haskell/multisplit-2.hs

@@ -0,0 +1,25 @@
+import Data.List (find, isPrefixOf)
+
+multiSplit :: [String] -> String -> [(String, String, Int)]
+multiSplit ds s =
+  let lng = length s
+      (ts, ps, o) =
+        foldl
+          (\(tokens, parts, offset) (c, i) ->
+              let inDelim = offset > i
+              in case (if inDelim
+                         then Nothing
+                         else find (`isPrefixOf` drop i s) ds) of
+                   Just x -> ([], (tokens, x, i) : parts, i + length x)
+                   Nothing ->
+                     ( if inDelim
+                         then tokens
+                         else c : tokens
+                     , parts
+                     , offset))
+          ([], [], 0)
+          (zip s [0 .. lng])
+  in reverse $ (ts, [], lng) : ps
+
+main :: IO ()
+main = print $ multiSplit ["==", "!=", "="] "a!===b=!=c"