Question

Here is a simple explanation of the problem. Keep in mind this isnt the real problem

Lets say in my language functions cannot return pointers and member vars cannot be references. Bison is complaining (with like 40 reduce/reduce problems) about not deducing if the type in type what is a function or member variable. I know it but its ridiculous to have >40 conflicts from this one line.

Class Name { ...
Type& func() {
Type* Var=0
Type What

How should i deal with this? should i use %glr-parser and set expect/expect-rr to a value? or should i use a Type that has everything and filter what is legal or not in code? It looks like my choices are have more conflicts/ambiguity VS writing more code to deal with it. I am not sure which is worse so i wonder if any of you guys had to deal with this.

Answer 1

You shouldn’t try to express type constraints in the grammar. This was proven pretty conclusively by the Algol-68 fiasco documented by Wirth and others.