Re: lint warnings from `bison -y' generated files

[Akim Demaille]

>>> "Paul" == Paul Eggert <address@hidden> writes:

 > OK, so it's impossible in general to shut off those messages with
 > /*CONSTCOND*/.  Then let's not bother to try.

You see me surprised!  You and I are militants of killing the
warnings, so I do understand Nicolas' point, in particular in
generated code.  This is somewhat inconsistent with your arguments
pro-alloca.


 >> Fixing all lint warnings will be a real pain !

 > Yes, at some point the cost exceeds the benefit.

Yep :(


 >  yyuserMerge (int yyn, YYSTYPE* yy0, YYSTYPE* yy1)
 >  {
 > -  /* `Use' the arguments.  */
 > -  (void) yy0;
 > -  (void) yy1;
 > +  /* Suppress unused-variable warnings.  */
 > +  yy0 = yy0;
 > +  yy1 = yy1;

Doh...  Not beautiful at all :(  How about defining
YY_ATTRIBUTE_UNUSED and see adjust its definition depending on the
tool (I hate to say that...).  This is also better documentation.


 > Index: data/lalr1.cc
 > ===================================================================
 > RCS file: /cvsroot/bison/bison/data/lalr1.cc,v
 > retrieving revision 1.106
 > diff -p -u -r1.106 lalr1.cc
 > --- data/lalr1.cc    2 Oct 2005 20:41:42 -0000       1.106
 > +++ data/lalr1.cc    5 Oct 2005 05:57:29 -0000
 > @@ -411,12 +411,12 @@ void
 >  yy::]b4_parser_class_name[::yysymprint_ (int yytype,
 >                           const semantic_type* yyvaluep, const 
 > location_type* yylocationp)
 >  {
 > -  /* Pacify ``unused variable'' warnings.  */
 > -  (void) yyvaluep;
 > -  (void) yylocationp;
 >    /* Backward compatibility, but should be removed eventually. */
 >    std::ostream& cdebug_ = *yycdebug_;
 > -  (void) cdebug_;
 > +
 > +  /* Suppress unused-variable warnings.  */
 > +  if (false)
 > +    yysymprint_ (yytype + !&cdebug_, yyvaluep, yylocationp);

This is really hackish and obscure.  This is also C++, for which we
have no evidence a Lint++ would be a problem.  As a matter of fact I
just read a book by C++ gurus that promote just evaluating the
variable to shush the compiler (without the ugly C style cast to
void).

But again, YY_ATTRIBUTE_UNUSED could be used.
 
 >    *yycdebug_ << (yytype < yyntokens_ ? "token" : "nterm")
 >           << ' ' << yytname_[yytype] << " ("
 > @@ -435,10 +435,9 @@ void
 >  yy::]b4_parser_class_name[::yydestruct_ (const char* yymsg,
 >                           int yytype, semantic_type* yyvaluep, 
 > location_type* yylocationp)
 >  {
 > -  /* Pacify ``unused variable'' warnings.  */
 > -  (void) yymsg;
 > -  (void) yyvaluep;
 > -  (void) yylocationp;
 > +  /* Suppress unused-variable warnings.  */
 > +  if (false)
 > +    yydestruct_ (yymsg, yytype, yyvaluep, yylocationp);
 
 >    YY_SYMBOL_PRINT (yymsg, yytype, yyvaluep, yylocationp);