Re: Feature request

[Hans Aberg]

On 20 Jun 2007, at 12:28, Fernando Ferreira wrote:

> I'm a huge fan of this project and I'm using it for several of my  
> small personal project (hopefully one day I will get to finish and  
> publish one of them). I use both flex and bison C++ Language  
> Interface (not that it has anything to do with the feature I'm  
> about to request) and one feature that is available on Flex that is  
> not on Bison is a macro that executes just before the rule action  
> is executed. On flex, it is YY_USER_ACTION (http://www.gnu.org/ 
> software/flex/manual/html_mono/flex.html#SEC14), but there is no  
> (documented) equivalent for it on Bison. I know there is the  
> YY_REDUCE_PRINT macro, but it is only for debug purposes, and not  
> meant (not to say not possible) to be overridden.
>
> The reason for my request is that, as bison generates LR parsers,  
> there is no way to, for instance, execute an action before a rule  
> is reduced, only after.

I have you tried to put it into yacc.c, somewhere between "yyreduce:"  
and "switch (yyn)"?

  Hans Aberg