ammar and
        attach a parse action to it that modifies the returned token list.
        Invoking C{transformString()} on a target string will then scan for matches,
        and replace the matched text patterns according to the logic in the parse
        action.  C{transformString()} returns the resulting transformed string.
        
        Example::
            wd = Word(alphas)
            wd.setParseAction(lambda toks: toks[0].title())
            
            print(wd.transformString("now is the winter of our discontent made glorious summer by this sun of york."))
        Prints::
            Now Is The Winter Of Our Discontent Made Glorious Summer By This Sun Of York.
        r