on your grammar before calling C{parseString}
           (see L{I{parseWithTabs}<parseWithTabs>})
         - define your parse action using the full C{(s,loc,toks)} signature, and
           reference the input string using the parse action's C{s} argument
         - explictly expand the tabs in your input string before calling
           C{parseString}
        
        Example::
            Word('a').parseString('aaaaabaaa')  # -> ['aaaaa']
            Word('a').parseString('aaaaabaaa', parseAll=True)  # -> Exception: Expected end of text
        r