Re: Two-pass parser or AST with Bison?

[Evan Lavelle]

Matthias Kramm wrote:

> I'll probably define myself some C macros so that I can at least
> write something like
>     E = E '+' E {pass2only append($1);append($3);append(OP_ADD);}
> .
> But it would of course be more nifty if the default behaviour 
> "execute an action only if the pass is 2" could be placed
> somewhere central.

You really want a bison equivalent of flex's YY_USER_ACTION, but I don't 
think there is one. You could hack the bison output if you're desperate 
- maybe something in/around YY_REDUCE_PRINT.

> Any pointers to a pure C AST implementation, by any chance?

There's a C runtime for Antlr, so I guess all the AST code has C 
versions as well - I don't think it existed when I needed it. The C++ 
version has ~80 .hpp and .cpp files for the AST bits (I think I found it 
in a lib directory somewhere in the source tree).

-Evan