Re: Conflicts in large grammar

[Hans Aberg]

On 8 Aug 2007, at 14:20, Laurence Finston wrote:

> I've now determined that using a more recent version of Bison  
> helps.  I
> was using 1.875.  I added a rule that caused Bison to abort and  
> then tried
> it with 2.1, which succeeded.  I ran both versions using input that  
> didn't
> cause 1.875 to fail and the number of shift/reduce conflicts differed.
>
> I've now installed Bison 2.3 and it works.

The Bison from the CVS works fine, too. :-)

> I will still try to get rid of
> unnecessary rules, though.  I'll also try to reduce or eliminate  
> the s/r
> conflicts, when I find the time.

> It would be nice to know exactly what makes Bison abort.  I suspect  
> it has
> to do with the states, but I wasn't able to understand why it would  
> fail
> in some cases and not in others.

It can be difficult. Some work has been done in order to extend the  
old Bison limits, just in order to enable larger grammars, but I do  
not know exactly its state. And only the latest version is developed.  
So if an older version does not work, the only option is to switch to  
the latest, and if that one does not work, trying to get that one fixed.

  Hans Aberg