June 2018 Update

Task/Multisplit/Haskell/multisplit-1.hs

@@ -0,0 +1,28 @@
+import Data.List
+       (isPrefixOf, stripPrefix, genericLength, intercalate)
+
+trysplit :: String -> [String] -> Maybe (String, String)
+trysplit s delims =
+  case filter (`isPrefixOf` s) delims of
+    [] -> Nothing
+    (d:_) -> Just (d, (\(Just x) -> x) $ stripPrefix d s)
+
+multisplit :: String -> [String] -> [(String, String, Int)]
+multisplit list delims =
+  let ms [] acc pos = [(acc, [], pos)]
+      ms l@(s:sx) acc pos =
+        case trysplit l delims of
+          Nothing -> ms sx (s : acc) (pos + 1)
+          Just (d, sxx) -> (acc, d, pos) : ms sxx [] (pos + genericLength d)
+  in ms list [] 0
+
+main :: IO ()
+main = do
+  let parsed = multisplit "a!===b=!=c" ["==", "!=", "="]
+  mapM_
+    putStrLn
+    [ "split string:"
+    , intercalate "," $ map (\(a, _, _) -> a) parsed
+    , "with [(string, delimiter, offset)]:"
+    , show parsed
+    ]