Re: Bison 1.30f

[Paul Eggert]

> From: Akim Demaille <address@hidden>
> Date: 10 Dec 2001 11:25:29 +0100

> | one should use
> |   #include <libgettext.h>
> | in the sources (system.h).
> 
> I know that, but I do fear picking up some wrong file.  I much prefer
> using qualified path in includes.

That's true in general, but in this particular case I don't think
there will be any real harm in using `#include "libgettext.h"'.
That's what several other packages use, including diffutils,
sharutils, and gettext itself.


> | One should then first have:
> | #ifndef YYSTACK_USE_ALLOCA
> |   // Check if alloca is avalable: If so,
> |      #define YYSTACK_USE_ALLOCA 1
> |   else must use malloc
> |      #define YYSTACK_USE_ALLOCA 0
> | #endif
> 
> This is no longer how it works: it now directly defines what it needs
> and no longer uses YYSTACK_USE_ALLOCA afterwards.

The method used in Bison 1.30f's bison.simple should have the same
effect as the above-quoted code, so I think we're OK here already.


> I tend to think that if people want to use Bison C parsers with C++,
> _they_ have to include the relevant headers.

But isn't his point that we're currently including C headers instead
of C++ headers, so we're infringing on the C++ user's namespace more
than we have to?  If so, the problem can't easily be fixed by users,
since our code will include the C headers anyway.


> When Bison outputs C++, we will include the right headers.

In what way is Bison not outputting valid C++ now?

Of course Bison could do a better job of outputting C++, but isn't the
code valid (albeit ugly) C++ code now?

If so, it seems to me that the following patch would be worthwhile
even before we modify Bison to output beautiful C++ code.  Hans, can
you please check whether it works for you with C++?  (It passes
Bison's 'make check' test for C.)

2001-12-10  Paul Eggert  <address@hidden>

        * src/bison.simple (YYSIZE_T, YYSTACK_ALLOC, YYSTACK_FREE):
        Do not infringe on the global user namespace when using C++.
        (YYFPRINTF, YYSTDERR): New macros, needed for the above.
        All uses of 'fprintf' changed.

--- bison-1.30f/src/bison.simple        Wed Dec  5 00:58:33 2001
+++ bison-1.30f-fix/src/bison.simple    Mon Dec 10 13:01:00 2001
@@ -32,7 +32,7 @@
    infringing on user name space.  This should be done even for local
    variables, as they might otherwise be expanded by user macros.
    There are some unavoidable exceptions within include files to
-   define necessary C library symbols; they are noted "INFRINGES ON
+   define necessary library symbols; they are noted "INFRINGES ON
    USER NAME SPACE" below.  */
 
 #if ! defined (yyoverflow) || defined (YYERROR_VERBOSE)
@@ -69,11 +69,18 @@
    /* Pacify GCC's `empty if-body' warning. */
 #  define YYSTACK_FREE(Ptr) do { /* empty */; } while (0)
 # else
-#  define YYSTACK_ALLOC malloc
-#  define YYSTACK_FREE(Ptr) free (Ptr)
-#  if defined (__STDC__) || defined (__cplusplus)
-#   include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
-#   define YYSIZE_T size_t
+#  ifdef __cplusplus
+#   include <cstdlib> /* INFRINGES ON USER NAME SPACE */
+#   define YYSIZE_T std::size_t
+#   define YYSTACK_ALLOC std::malloc
+#   define YYSTACK_FREE std::free
+#  else
+#   ifdef __STDC__
+#    include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
+#    define YYSIZE_T size_t
+#   endif
+#   define YYSTACK_ALLOC malloc
+#   define YYSTACK_FREE free
 #  endif
 # endif
 
@@ -128,9 +135,16 @@ union yyalloc
 #if ! defined (YYSIZE_T) && defined (size_t)
 # define YYSIZE_T size_t
 #endif
-#if ! defined (YYSIZE_T) && (defined (__STDC__) || defined (__cplusplus))
-# include <stddef.h> /* INFRINGES ON USER NAME SPACE */
-# define YYSIZE_T size_t
+#if ! defined (YYSIZE_T)
+# ifdef __cplusplus
+#  include <cstddef> /* INFRINGES ON USER NAME SPACE */
+#  define YYSIZE_T std::size_t
+# else
+#  ifdef __STDC__
+#   include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#   define YYSIZE_T size_t
+#  endif
+# endif
 #endif
 #if ! defined (YYSIZE_T)
 # define YYSIZE_T unsigned int
@@ -206,11 +220,23 @@ while (0)
 
 /* Enable debugging if requested.  */
 #if YYDEBUG
-# include <stdio.h>
+
+# ifndef YYFPRINTF
+#  ifdef __cplusplus
+#   include <cstdio.h> /* INFRINGES ON USER NAME SPACE */
+#   define YYFPRINTF std::fprintf
+#   define YYSTDERR std::stderr
+#  else
+#   include <stdio.h> /* INFRINGES ON USER NAME SPACE */
+#   define YYFPRINTF fprintf
+#   define YYSTDERR stderr
+#  endif
+# endif
+
 # define YYDPRINTF(Args)                       \
 do {                                           \
   if (yydebug)                                 \
-    fprintf Args;                              \
+    YYFPRINTF Args;                            \
 } while (0)
 /* Nonzero means print parse trace. [The following comment makes no
    sense to me.  Could someone clarify it?  --akim] Since this is
@@ -443,7 +469,7 @@ yyparse (YYPARSE_PARAM_ARG)
      rule. */
   int yylen;
 
-  YYDPRINTF ((stderr, "Starting parse\n"));
+  YYDPRINTF ((YYSTDERR, "Starting parse\n"));
 
   yystate = 0;
   yyerrstatus = 0;
@@ -539,14 +565,14 @@ yyparse (YYPARSE_PARAM_ARG)
       yylsp = yyls + yysize - 1;
 #endif
 
-      YYDPRINTF ((stderr, "Stack size increased to %lu\n",
+      YYDPRINTF ((YYSTDERR, "Stack size increased to %lu\n",
                  (unsigned long int) yystacksize));
 
       if (yyssp >= yyss + yystacksize - 1)
        YYABORT;
     }
 
-  YYDPRINTF ((stderr, "Entering state %d\n", yystate));
+  YYDPRINTF ((YYSTDERR, "Entering state %d\n", yystate));
 
   goto yybackup;
 
@@ -573,7 +599,7 @@ yybackup:
 
   if (yychar == YYEMPTY)
     {
-      YYDPRINTF ((stderr, "Reading a token: "));
+      YYDPRINTF ((YYSTDERR, "Reading a token: "));
       yychar = YYLEX;
     }
 
@@ -584,7 +610,7 @@ yybackup:
       yychar1 = 0;
       yychar = YYEOF;          /* Don't call YYLEX any more */
 
-      YYDPRINTF ((stderr, "Now at end of input.\n"));
+      YYDPRINTF ((YYSTDERR, "Now at end of input.\n"));
     }
   else
     {
@@ -595,13 +621,14 @@ yybackup:
        which are defined only if `YYDEBUG' is set.  */
       if (yydebug)
        {
-         fprintf (stderr, "Next token is %d (%s", yychar, yytname[yychar1]);
+         YYFPRINTF (YYSTDERR, "Next token is %d (%s",
+                    yychar, yytname[yychar1]);
          /* Give the individual parser a way to print the precise
             meaning of a token, for further debugging info.  */
 # ifdef YYPRINT
-         YYPRINT (stderr, yychar, yylval);
+         YYPRINT (YYSTDERR, yychar, yylval);
 # endif
-         fprintf (stderr, ")\n");
+         YYFPRINTF (YYSTDERR, ")\n");
        }
 #endif
     }
@@ -633,7 +660,8 @@ yybackup:
     YYACCEPT;
 
   /* Shift the lookahead token.  */
-  YYDPRINTF ((stderr, "Shifting token %d (%s), ", yychar, yytname[yychar1]));
+  YYDPRINTF ((YYSTDERR, "Shifting token %d (%s), ",
+             yychar, yytname[yychar1]));
 
   /* Discard the token being shifted unless it is eof.  */
   if (yychar != YYEOF)
@@ -694,13 +722,13 @@ yyreduce:
     {
       int yyi;
 
-      fprintf (stderr, "Reducing via rule %d (line %d), ",
-              yyn, yyrline[yyn]);
+      YYFPRINTF (YYSTDERR, "Reducing via rule %d (line %d), ",
+                yyn, yyrline[yyn]);
 
       /* Print the symbols being reduced, and their result.  */
       for (yyi = yyprhs[yyn]; yyrhs[yyi] > 0; yyi++)
-       fprintf (stderr, "%s ", yytname[yyrhs[yyi]]);
-      fprintf (stderr, " -> %s\n", yytname[yyr1[yyn]]);
+       YYFPRINTF (YYSTDERR, "%s ", yytname[yyrhs[yyi]]);
+      YYFPRINTF (YYSTDERR, " -> %s\n", yytname[yyr1[yyn]]);
     }
 #endif
 %% actions /* The action file replaces this line. */
@@ -716,10 +744,10 @@ yyreduce:
   if (yydebug)
     {
       short *yyssp1 = yyss - 1;
-      fprintf (stderr, "state stack now");
+      YYFPRINTF (YYSTDERR, "state stack now");
       while (yyssp1 != yyssp)
-       fprintf (stderr, " %d", *++yyssp1);
-      fprintf (stderr, "\n");
+       YYFPRINTF (YYSTDERR, " %d", *++yyssp1);
+      YYFPRINTF (YYSTDERR, "\n");
     }
 #endif
 
@@ -815,7 +843,7 @@ yyerrlab1:
       /* return failure if at end of input */
       if (yychar == YYEOF)
        YYABORT;
-      YYDPRINTF ((stderr, "Discarding token %d (%s).\n",
+      YYDPRINTF ((YYSTDERR, "Discarding token %d (%s).\n",
                  yychar, yytname[yychar1]));
       yychar = YYEMPTY;
     }
@@ -861,10 +889,10 @@ yyerrpop:
   if (yydebug)
     {
       short *yyssp1 = yyss - 1;
-      fprintf (stderr, "Error: state stack now");
+      YYFPRINTF (YYSTDERR, "Error: state stack now");
       while (yyssp1 != yyssp)
-       fprintf (stderr, " %d", *++yyssp1);
-      fprintf (stderr, "\n");
+       YYFPRINTF (YYSTDERR, " %d", *++yyssp1);
+      YYFPRINTF (YYSTDERR, "\n");
     }
 #endif
 
@@ -894,7 +922,7 @@ yyerrhandle:
   if (yyn == YYFINAL)
     YYACCEPT;
 
-  YYDPRINTF ((stderr, "Shifting error token, "));
+  YYDPRINTF ((YYSTDERR, "Shifting error token, "));
 
   *++yyvsp = yylval;
 #if YYLSP_NEEDED