Data commit

Task/Substring/Haskell/substring-2.hs

@@ -0,0 +1,31 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+import qualified Data.Text as T (Text, take, drop, init, breakOn)
+import qualified Data.Text.IO as O (putStrLn)
+
+fromMforN :: Int -> Int -> T.Text -> T.Text
+fromMforN n m s = T.take m (T.drop n s)
+
+fromNtoEnd :: Int -> T.Text -> T.Text
+fromNtoEnd = T.drop
+
+allButLast :: T.Text -> T.Text
+allButLast = T.init
+
+fromCharForN, fromStringForN :: Int -> T.Text -> T.Text -> T.Text
+fromCharForN m needle haystack = T.take m $ snd $ T.breakOn needle haystack
+
+fromStringForN = fromCharForN
+
+-- TEST ---------------------------------------------------
+main :: IO ()
+main =
+  mapM_
+    O.putStrLn
+    ([ fromMforN 9 10
+     , fromNtoEnd 20
+     , allButLast
+     , fromCharForN 6 "话"
+     , fromStringForN 6 "大势"
+     ] <*>
+     ["天地不仁仁者人也🐒话说天下大势分久必合🍑合久必分🔥"])