<irstas at gmail.com> wrote in message news:1175617229.555905.175790 at w1g2000hsg.googlegroups.com... >> There is a stray leading space in it. > > Nah, I'd say there's a stray ([^0-9]) after the space. If you regard the spaces as being a required part of the postfix grammar, it would be simpler. But who would design a language where white space was significant ;)