Re: reentrant flex, bison glue

[Akim Demaille]

| > I'm very worried when I see two packages having an increased
| > impedance.
| 
| I've only done what was ALREADY IN BISON! Below is code from bison, 
| followed by code from flex:

Maybe you'll think I'm dishonest in the following sentence, but...
I don't see where Bison mentions Flex and binds the Flex community
with the following prototypes.

 
| /***** GENERATED BY BISON  *****/
| /* Automatic implicit declaration of yylex. [Comment added by millaway] */
| #ifndef YYPURE
| #define YYLEX       yylex()
| #endif
| #ifdef YYPURE
| #ifdef YYLSP_NEEDED
| #ifdef YYLEX_PARAM
| #define YYLEX       yylex(&yylval, &yylloc, YYLEX_PARAM)
| #else
| #define YYLEX       yylex(&yylval, &yylloc)
| #endif
| #else /* not YYLSP_NEEDED */
| #ifdef YYLEX_PARAM
| #define YYLEX       yylex(&yylval, YYLEX_PARAM)
| #else
| #define YYLEX       yylex(&yylval)
| #endif
| #endif /* not YYLSP_NEEDED */
| #endif
| 
| 
| /**** GENERATED BY FLEX *****/
| /* Automatic explicit declaration of yylex. */
| #ifdef YY_REENTRANT_BISON_PURE
| #  ifdef YYLTYPE 
| #    ifdef YY_USE_PROTOS
| #      define YY_LEX_ARGS (YYSTYPE * yylvalp, YYLTYPE * yyllocp YY_LAST_ARG)
| #    else
| #      define YY_LEX_ARGS (yylvalp, yyllocp YY_LAST_ARG) \
|                    YYSTYPE * yylvalp; YYLTYPE * yyllocp; YY_DECL_LAST_ARG
| #    endif
| #  else
| #    ifdef YY_USE_PROTOS
| #      define YY_LEX_ARGS (YYSTYPE * yylvalp YY_LAST_ARG)
| #    else
| #      define YY_LEX_ARGS (yylvalp YY_LAST_ARG) \
|                              YYSTYPE * yylvalp; YY_DECL_LAST_ARG
| #    endif
| #  endif
| #else
| #  ifdef YY_USE_PROTOS
| #    define YY_LEX_ARGS (YY_ONLY_ARG)
| #  else
| #    define YY_LEX_ARGS (YY_ONLY_ARG) YY_DECL_LAST_ARG
| #  endif
| #endif
| extern int yylex YY_PROTO( YY_LEX_ARGS );

I'm happy to see that.  How about this alternative implementation:

        Flex does need make an hypothesis on Bison.  But Flex
        documents the macro YY_LEX_ARGS and Bison defines it in the
        header file.

It seems to me that this is saner.  What do you think?  This way it is
not named `Bison' or whatever in the Flex' option, and if something
changes in Bison, then we can handle by ourselves the compatibility?
And Flex does not have this big chunk.