I know this has come up before. Hopefully I'm not about to repeat a lot. Debugging this stuff just seems really hard. And significantly harder than what I've experienced working with e.g. Yacc.
Hypothesis: Yacc had a lot of time to bake before I ever found it. PEGs are new, so there's been less overall experience with debugging them. I've experimented in what little time I can devote with OMeta, PetitParser, and Treetop. The debugging experience has been roughly consistent across all three. One particular issue which has bugged me: memoization seems to carry a lot of instance-state that's really hard to comprehend when the grammar isn't working as I expect. It's just really hard to use that ocean of information to figure out what I've done wrong. Given that with these new parsing technologies, we're pretty lucky to see "parse error" as an error message, I can't help but think that it's worth studying debugging strategies. Heh. :D I'm really not complaining, I'm just pointing it out. Has anyone here found any technique(s) which makes debugging a grammar written for a PEG/packrat less of a pain in the butt? I'd be really interested in hearing about it. _______________________________________________ fonc mailing list fonc@vpri.org http://vpri.org/mailman/listinfo/fonc
