I currently have been tinkering with a compiler tool which provides Yacc and Lex-like functionality (with an LR(1) compiler parser) in the OCYacc/OCLex tools.
Basically I needed a version of yacc and lex which could build a compiler, but generate a re-entrant Objective-C class.
Well, recently I’ve been adding a code generator to generate C++ code. It’s still pretty experimental, but the code is now checked into GitHub. Check it out.
More information can be found here.