eternal-0.0.8: src/Control/Eternal/String.hs

module Control.Eternal.String
  ( trim
  ) where

import Data.Char (isSpace)

trim :: String -> String
trim xs = dropSpaceTail "" $ dropWhile isSpace xs

dropSpaceTail :: String -> String -> String
dropSpaceTail maybeStuff "" = ""
dropSpaceTail maybeStuff (x:xs)
        | isSpace x = dropSpaceTail (x:maybeStuff) xs
        | null maybeStuff = x : dropSpaceTail "" xs
        | otherwise       = reverse maybeStuff ++ x : dropSpaceTail "" xs