BtYacc is the bee's knees! It is yacc but it can backtrack so it can handle conflicts.

this makes writing grammars much happier than using normal yacc: it allows you to write a grammar which more closely mirrors how one might think about the constructs of a language, rather than going through all manner of needless contortions to avoid conflicts. it also allows you to deal with garmmars that are inherently ambiguous.

BUT WAIT THERE'S MORE!

you only incur extra overhead compared to yacc when you actually backtrack.