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Re: switch from byacc to bison

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Dave Mitchell
February 27, 2004 13:53
Re: switch from byacc to bison
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On Fri, Feb 27, 2004 at 11:39:32AM +0000, Nicholas Clark wrote:
> On Sun, Feb 15, 2004 at 01:17:27AM +0000, Dave Mitchell wrote:
> > On Sat, Feb 14, 2004 at 05:22:46PM +0000, Nicholas Clark wrote:
> > > On Sat, Feb 14, 2004 at 01:46:06PM +0000, Dave Mitchell wrote:
> > > 
> > > > Anyway, I was envisaging that the patch might go into 5.8.x, but it's
> > > > definitely too scary for anything earlier. All the old byacc parser
> > > 
> > > Depends how scarey it looks. How close is its output to the current *.c files,
> > > given the same input?
> > 
> > Well, its like not close at all really. The boilerplate code is totally
> > different, and the tables generally have different names and totally
> > different content. Also, error recovery seems to be better.
> But thinking about merging it, I ask myself "Is it binary compatible?"
> and I don't think I can answer this myself.

Well, I *think* it's binary compatible. It makes a whole bunch of Perl
vars obsolete (like PL_yydebug), but in the main patch (22302) I filled
thinggyvar.h with placeholders, and in a seaprate patch for 5.9.x only
(22303) I removed them altogether. Of course if someone's written
some XS code that directly calls Perl_yylex or uses PL_yydebug, then it
will break, but I can't really see that happening.

So in short, yes, but don't ask me to stake my mother's life on it!

"The GPL violates the U.S. Constitution, together with copyright,
antitrust and export control laws"
    -- SCO smoking crack again.

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