gistfile1.hs

>   module Scan where
>   import Char

>   tokenize [] = []
>   tokenize (x:xs)
>       | isSpace x = tokenize xs
>       | isDigit x = fst (span isDigit (x:xs)) : tokenize (snd (span isDigit (x:xs)))
>       | isAlpha x = fst (span isAlpha (x:xs)) : tokenize (snd (span isAlpha (x:xs)))
>       | isSym x = fst (span isSym (x:xs)) : tokenize (snd (span isSym (x:xs)))

>   isSym c =  c `elem` "!@#$%&*+./<=>?\\^|:-~()"