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).

>>15
Have you ever written a parser for anything non-trivial in BNF? I'm assuming you've done it several times with regex.

This isn't a question of power, it's a question of readability. I have doubts about anyone who thinks a modern "regex" is anywhere in the same league as bachus-naur form. Parsing with regular expressions is plain ugly, and I have yet to see an example otherwise.

But, feel free to enlighten.