Haskell and Regex - Why doesn't my function eliminate RedundantSpaces?

Text.Regex

uses Posix regular expressions and does not contain a shorthand acronym \s

(this is a perl extension that many other implementations do). You can use a group of characters instead [:space:]

, like:

eliminateRedundantSpaces text =
   subRegex (mkRegex "[[:space:]]+") text " "