Re: [off-topic] flex/bison compatibility issues using C++

[Josh Shinavier]

That helps, thanks (we were using Bison 3.5).  I got our network admin to 
install 1.875 but am encountering the same errors (yylex and yyerror 
undeclared in [filename].tab.c).  If I add the following to  my Bison 
header, gcc doesn't complain about yylex or yyerror but reports a parse 
error before the "goto yyerrlab2;" statement in [filename].tab.c:

typedef struct yy_buffer_state *YY_BUFFER_STATE;

extern "C" {
 YY_BUFFER_STATE yy_scan_string( const char * );
 void            yy_delete_buffer( YY_BUFFER_STATE );
       int yyerror(const char *);
       int yyparse(void);
       int yylex(void);
       int yywrap()
       {
               return 1;
       }
}

Now at least I know it's definitely something about my input files which is 
causing failure...

Josh Shinavier



> Recent versions of bison no longer have a bison.simple; they have a
> yacc.c.  If you don't want to worry about growing the stack when it
> overflows, and if your %union contains objects that don't need
> destructors, then it should just work "out of the box".  You can try
> it yourself wwith the latest test version:
>
> ftp://alpha.gnu.org/gnu/bison/bison-1.875d.tar.gz
>
> There is also a C++ skeleton called lalr1.cc that is also supposed to
> work, though it hasn't been tested as much.
>
> > I need my instructor to be able to compile the parser on his
> > machine.
>
> I'm afraid that there's no single set of instructions that will work
> with C++ for all versions of Bison and/or Yacc.

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