Re: Problems with bison creating a GLR parser

[Paul N. Hilfinger]

OK.  The problem is that support for semantic references with non-
positive indices (e.g., $-1 or $0) is currently missing in GLR mode
(that is, when a GLR parser has multiple stacks).  Even when programs
do not explicitly use $0, etc., they are implicitly present in
embedded semantic actions, since, for example,

    X: Y Z { f ($1); } Q

gets converted into something like

     X: Y Z @1 Q

     @1: { f ($-1); }

In a day or two, I will provide the necessary changes to glr.c, plus a
regression test.

Paul