how do i wrote parser?

I have a pretty good educational understanding of computer grammar theory, so I get the concepts behind parsers and context-free grammars, but I've never actually implemented a parser.  And now I need to write one.

Specifically, I'm looking to write a loader for .md5mesh files (they are text format).  Let's say I'm able to get a grammar for it written on paper that matches that file format's general structure.  Where do I start in code?  This is fortunately not as complicated as a programming language's language, since it's a format that's about data and not code, but it's still a somewhat more complicated 3D format than, say, the Alias Wavefront .obj format (where reading and parsing is as simple as a for loop and sscanf -- but that format doesn't support skeletal animation and other things the way .md5mesh does).

>>9
Regexes become understandable and harder to fail at once you've gotten used to how the backtracking automata works. They have the advantage of being almost universally available and extremely productive. They are several order of magnitudes more comfortable and faster to use when you're doing Python, Ruby, or similar.

BTW, I'm not a Perl guy, and I don't like Perl's $%/%&(%//#<>+ syntax for *EVERYTHING*. But I love PCRE. It's a matter of using the right tool for every job.