The Lua source code is also a masterclass in C, I recommend it to anyone learning that language. It's big enough to be an involved implementation, but small and focused and well-organized enough to (at least roughly) understand what's going on at the various layers. It's a very solidly-written mass of portable C, with only minor exceptions.

Oh I hadn't considered looking at the source but considering how minimal and clean Lua is I should have assumed so :)

Thanks for the tip. That should make for a fun weekend