If I was to use Parse::RecDescent, would it go faster?

Parse::RecDescent is known to be slow. So much so that Damian Conway want(?:ed|s) to write Parse::RecDescent::Fast. Or something like that.

Another alternative is to use Parse::Yapp (Yet Another Perl Parser). I haven't used it personally, but a number of people who have have appreciated the speed. They have also appreciated less, the fact that it is drop-in compatible with yacc(1). No-one knows yacc anymore. stefp was threatening a while back to write a front-end to P::Y to get it to accept P::RD's input, but I don't know if he got round to doing so.