Re: push parser

[Bob Rossi]

On Thu, Sep 21, 2006 at 07:03:47AM -0400, Bob Rossi wrote:
> On Wed, Sep 20, 2006 at 09:58:30PM -0700, Paul Eggert wrote:
> > >> One way to address this issue would be to have two entry points:
> > >> 
> > >>        status = yypushparse (ctx, ch, yylloc);
> > >> 
> > >> for tokens that have no semantic value, and
> > >> 
> > >>        status = yypushparseval (ctx, ch, yylval, yylloc);
> > >> 
> > >> for tokens that do.
> > >> 
> > >> Another possibility, which will avoid a copy in some cases if semantic
> > >> values are large, is to pass a pointer:
> > >> 
> > >>        status = yypushparse (ctx, ch, &yylval, yylloc);
> > >> 
> > >> where you pass a NULL pointer if the token has no semantic value.  If
> > >> the copying issue is of concern, it may also make sense to pass yylloc's
> > >> address too:
> > >> 
> > >>        status = yypushparse (ctx, ch, &yylval, &yylloc);
> > >> 
> > >> I don't know whether the copying concern is enough to affect
> > >> performance, though.
> > >
> > > I'm not decided on how to modify the yypushparse function parameters.
> > > Have you made up your mind?
> > 
> > If it doesn't matter to you, let's use the second method (passing
> > the addresses).  We can always change it later if it turns
> > out to have a problem.
> 
> OK, I liked the second approach better myself. I'll look into it.

I have a small patch that get's me this far:
  status = yypushparse (ctx, ch, &yylval);

What should I do about yylval?

I can attempt to make yypushparse have an extra parameter when locations
are enabled. Does that sound correct?

Thanks,
Bob Rossi