Sam Barnett-Cormack schrieb: > Jim Idle wrote: >> The things you are seeing are standard things that happen when you >> start out by typing in a grammar from the normative grammar of some >> language spec. Such language specs are not really written with writing >> a parser spec in mind (most say this) and even if they are they are >> usually written with yacc/bison in mind. Consequently they are full of >> ambiguities that you must left factor as you go. > > Well, I didn't just blindly copy them out, although I'll admit I got > tied up in left-recursion issues. The grammar actually seems to have > some ambiguities that would be ambiguous anywhere, actually, which is a > pain in the neck, by c'est la vie. > > I also didn't want to refactor it anymore than necessary because there > is a relationship between the structure of rules in the standard and the > semantic structure, which should help at later stages.
You can undo the left-factoring when doing rewrites of the AST. It helps if you use imaginary tokens to disambiguate ambiguities for the tree parser. Johannes List: http://www.antlr.org/mailman/listinfo/antlr-interest Unsubscribe: http://www.antlr.org/mailman/options/antlr-interest/your-email-address --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "il-antlr-interest" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/il-antlr-interest?hl=en -~----------~----~----~----~------~----~------~--~---
