Re: Problem with Bison 1.35

[Akim Demaille]

| Vojtech Toman wrote:
|  > parser generated by 1.28 was ok, but parser generated by 1.35
|  > crashes with stack overflow
| 
| I'm very new to the world of Bison and Flex, but I spent the better
| part of today figuring this one out, and just located this mailing
| list to share what I found.
| :-)

Welcome :)

| The problem seems to be this code in bison.simple, which was added in
| 1.34a according to the ChangeLog:
| 
| #if (! defined (yyoverflow) \
|      && (! defined (__cplusplus) \
|        || (YYLTYPE_IS_TRIVIAL && YYSTYPE_IS_TRIVIAL)))
| 
| The idea is that if using C++, all the stack-growth code is only valid
| if both YYLTYPE and YYSTYPE are trivial types. Makes sense.

Yep.

| However, I don't use the location stack (that the right terminology?),
| and so reader_output_yylsp() is never called, code to define
| YYLSP_NEEDED and YYLTYPE is not written, and most importantly
| YYLTYPE_IS_TRIVIAL is never defined, and my stacks will never grow.

| I believe the correct solution is to not require YYLTYPE_IS_TRIVIAL in
| this conditional if YYLTYPE (or should it be YYLSP_NEEDED ?) is
| undefined.

Correct.  That's what I have in CVS Bison:

#ifndef YYLTYPE
typedef struct yyltype
{
  int first_line;
  int first_column;
  int last_line;
  int last_column;
} yyltype;
# define YYLTYPE b4_ltype
# define YYLTYPE_IS_TRIVIAL 1
#endif

Indeed, 1.35 has a problem wrt this :(  Would you give a try to 1.49b?
You *might* be able to fetch it from

        http://www.lrde.epita.fr/~akim/download/bison-1.49b.tar.gz
or
        http://www.lrde.epita.fr:800/~akim/download/bison-1.49b.tar.gz