Hello, Many languages provide the 'chop' or 'trip' function but Data.List does not. I would like to add a new function called 'tailDropWhile' so that people can easily implement 'chop' for String: chop :: String -> String chop = tailDropWhile isSpace The definition of tailDropWhile is as follows: {- wren ng thornton's version. This is lazier than Aoe's one. Out and inP implement push-down automata. -} tailDropWhile :: (a -> Bool) -> [a] -> [a] tailDropWhile p = out where out [] = [] out (x:xs) | p x = inP [x] xs | otherwise = x : out xs inP _ [] = [] inP ss (x:xs) | p x = inP (x:ss) xs | otherwise = reverse ss ++ x : out xs {- Mitsutoshi Aoe's version. This is faster is many cases but more strict. Just for reference. tailDropWhile :: (a -> Bool) -> [a] -> [a] tailDropWhile p = foldr go [] where go x xs | p x && null xs = [] | otherwise = x:xs -} For more information, please read: http://www.mail-archive.com/haskell-cafe@haskell.org/msg93192.html Discussion period: 2 weeks. Regards, --Kazu