Treetop is great - I have previously written parsers using yacc and lex, and I found treetop to be around about 2 orders of magnitude more productive. That sai

Treetop is great - I have previously written parsers using yacc and lex, and I found treetop to be around about 2 orders of magnitude more productive. That said, I don't know that I would want to use it on large files with a complex grammar :/