    # File lib/facets/core/string/word_filter.rb, line 17
      def word_filter! #:yield:
        rest_of_string = self
        wordfind = /(\w+)/
        offset = 0
        while wmatch = wordfind.match(rest_of_string)
          word = wmatch[0]
          range = offset+wmatch.begin(0) ... offset+wmatch.end(0)
          rest_of_string = wmatch.post_match
          self[range] = yield( word ).to_s
          offset = self.length - rest_of_string.length
        end
        self
      end