Well, actually I'm using yapp to build a parser, and I can tell you that it works exactly like yacc. I think you should definitely learn to use yacc and probably lex before. Reading about grammars and automatons might also be helpful. I think the best docs are the ones on bison and flex (GNU versions of yacc and lex). You might also take a look at the O'Reilly book "Lex & Yacc".