In Haskell, how do you trim whitespace from the beginning and end of a string?

Question

How do you trim whitespace from the start and end of a string?

trim \"  abc \" 

=>

\"abc\"

Edit:

Ok, let me be a little cleare

Answer 1

Along the lines of what other people have suggested, you can avoid having to reverse your string by using:

import Data.Char (isSpace)

dropFromTailWhile _ [] = []
dropFromTailWhile p item
  | p (last items) = dropFromTailWhile p $ init items
  | otherwise      = items

trim :: String -> String
trim = dropFromTailWhile isSpace . dropWhile isSpace