I've used Boost.Spirit. I'll say that the syntax is heavy but once you're used to it, it's actually rather easy to use. However, I'm looking for something a bit lighter. Would anyone care to share your opinion on what to use?
Spirit is heavy. Like, http://www.collegehumor.com/video/3349814/your-mother big. It supposedly can be heavily reduced but I don't like that it's also a play off of C++ syntax. That's fine but it's kinda confusing at times...
Looks good. I'll perform a benchmark between Spirit and whatever is generated by Bison/Flex. I'll probably also check out ANTLR although I'm not really sure what ANTLR is for quite yet...