Allegro's version of yacc

Hi,

I'm using Allegro 8 Express edition.  I am working on a project that uses
cl-yacc.  Allegro includes a version of yacc that appears to be based on
cl-yacc, but the interface has changed in a number of ways.  I can't use cl-yacc
with the allegro version, and my attempt to remove the allegro version of yacc
(the yacc.fasl in <allegro-root>/code/ ) leads to a cascade of problems, causing
regexp to fail, followed by osi, ...   In general, this is not the direction I
want to go in anyway.  What I really need is documentation (or at least the
source code!) for the allegro version of yacc.

Is there ANY DOCUMENTATION on the allegro version of yacc?

Thanks,

-Clay