Re: Feature request

[Evan Lavelle]

Fernando Ferreira wrote:

> 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've never tried an action at the start of a rule, but I'm pretty sure 
that you can do it. Look up 'embedded actions' in the O'Reilly lex&yacc 
book, or 3.5.5 'Actions in mid-rule' in the Bison 2.0 manual. It may be 
difficult to avoid conflicts, though. According to the O'Reilly book, 
yacc implements embedded actions using the technique described at the 
end of 3.5.5 ("Another solution is to bury the action inside a 
nonterminal symbol which serves as a subroutine...").

Evan