On 31/03/2009, at 2:35 AM, Emmanuel Onzon wrote: > > Roughly Felix would benefit from ability to add new productions by > "pushing" them onto a grammar stack, and later "forget" these > productions. > > I conceive this as a purely functional operation, not a modification, > working just like "scopes" in programming languages (because that's > precisely the context in which the feature is needed :) > > This is exactly how extending the grammar works with dypgen, > unless I'm missing something. >
yes but it can't be done without priorities: there's no way to "push" a grammar production into a chain otherwise. Merely adding another case to a non-terminal's RHS production list is not enough to add a new operator, since the list is closed off by a tail jump to the next precedence. Having priorities allows this because you can insert one between two others, Hmm. Note this required deleting a priority and adding two more if they're not transitive .. hmmm ... -- john skaller skal...@users.sourceforge.net ------------------------------------------------------------------------------ _______________________________________________ Felix-language mailing list Felix-language@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/felix-language
