[andrewcooke]

in case it's not clear - the "regular expressions" he's using are perl's (well, based on perl's - PCRE) which are notoriously extended past the theoretical definition, or past what almost all other regexp libs / languages provide.

the examples won't work in python or java, for example.

[abecedarius]

Right. In Python you might check out my https://github.com/darius/peglet/blob/master/peglet.py which is PEG-based but tries to feel like a modest extension of the built-in re module.