Re: C99 in Bison

[Akim Demaille]

Le 20 août 09 à 20:20, Joel E. Denny a écrit :

> A couple of years ago, Paul Eggert recommended we wait a couple of  
> years
> at least to start requiring users to have C99 compilers in order to  
> build
> Bison:
>
>  http://lists.gnu.org/archive/html/bison-patches/2007-05/msg00012.html
>
> How about now?

I have no opinion about this.  What are the others doing?  Say  
coreutils for instance :)

>  I'd love to be able to do things like:
>
>  void
>  foo (int *array, size n)
>  {
>    int array2[n]; // variable-length array
>    for (int i = 0; i < n; ++i) // mixed declarations and code
>      {
>        // Single-line comments, which are so tempting that we've  
> already
>        // begun using them.  Oops.
>      }
>  }
>
> If this is ok, we should probably add a configure.ac check for C99.
>
> And what about C99 for building Bison-generated parsers?

I doubt we can do that.  For a start we could move to C90 in yacc.c :)

> #ifdef YYPARSE_PARAM
> #if (defined __STDC__ || defined __C99__FUNC__ \
>      || defined __cplusplus || defined _MSC_VER)
> int
> yyparse (void *YYPARSE_PARAM)
> #else
> int
> yyparse (YYPARSE_PARAM)
>     void *YYPARSE_PARAM;
> #endif
> #else /* ! YYPARSE_PARAM */
> #if (defined __STDC__ || defined __C99__FUNC__ \
>      || defined __cplusplus || defined _MSC_VER)
> int
> yyparse (void)
> #else
> int
> yyparse ()
>
> #endif
> #endif

If I read correctly our parse-gram.c, we have two errors:

> # ifndef yytnamerr
> /* Copy to YYRES the contents of YYSTR after stripping away  
> unnecessary
>    quotes and backslashes, so that it's suitable for yyerror.  The
>    heuristic is that double-quoting is unnecessary unless the string
>    contains an apostrophe, a comma, or backslash (other than
>    backslash-backslash).  YYSTR is taken from yytname.  If YYRES is
>    null, do not copy; instead, return the length of what the result
>    would have been.  */
> static YYSIZE_T
> yytnamerr (char *yyres, const char *yystr)
> {


and

> static YYSIZE_T
> yysyntax_error (char *yyresult, int yystate, int yytoken)
> {

All the other functions are KnR compliant too.  Maybe we should poll  
the audience, say via NEWS.