In ghci:
ghci > urlDecode "http://twitter.com/fred/statuses/200"
"http://twitter.com/fred/statuses/200"
ghci > urlDecode "http://twitter.com/%user_screen_name%/statuses/%id%"
"http://twitter.com/*** Exception: Char.digitToInt: not a digit 'u'
It would be vastly nicer if urlDecode's type was something like String -> Either String String.
In ghci:
It would be vastly nicer if
urlDecode's type was something likeString -> Either String String.