FYI: Token enums

[Akim Demaille]

This is what Paul suggested.  Robert, I think everybody agrees that
for C++, you ought to use a namespace with the parser class with const
ints instead of enums.  Now that there is m4_map_sep, it should be
easy for you.

Here is a sample:

/tmp % cat foo.y                                                 nostromo 10:41
%token a b c d e f g
%%
exp: a;
%%
/tmp % ~/src/bison-exp/tests/bison foo.y -d                      nostromo 10:41
/tmp % cat foo.tab.h                                             nostromo 10:42
#ifndef BISON_FOO_TAB_H
# define BISON_FOO_TAB_H

#ifndef YYTOKENTYPE
# if defined (__STDC__) || defined (__cplusplus)
   /* Put the tokens into the symbol table, so that GDB and other debuggers
      know about them.  */
   enum yytokentype {
     enum a = 258,
     enum b = 259,
     enum c = 260,
     enum d = 261,
     enum e = 262,
     enum f = 263,
     enum g = 264
   };
   /* POSIX requires `int' for tokens in interfaces.  */
#  define YYTOKENTYPE int
# endif
#endif
#define a 258
#define b 259
#define c 260
#define d 261
#define e 262
#define f 263
#define g 264


#ifndef YYSTYPE
typedef int
yystype;
# define YYSTYPE yystype
#endif

extern YYSTYPE yylval;


#endif /* not BISON_FOO_TAB_H */

/tmp %                                                           nostromo 10:42


Index: ChangeLog
from  Akim Demaille  <address@hidden>

        * data/bison.simple (b4_token_enum): New.
        (b4_token_defines): Use it to output tokens both as #define and
        enums.
        Suggested by Paul Eggert.
        * src/output.c (token_definitions_output): Don't output spurious
        white spaces.

Index: TODO
===================================================================
RCS file: /cvsroot/bison/bison/TODO,v
retrieving revision 1.55
diff -u -u -r1.55 TODO
--- TODO 2 May 2002 16:12:35 -0000 1.55
+++ TODO 3 May 2002 08:40:20 -0000
@@ -34,26 +34,6 @@
        PDP-10 ports :-) but they should probably be documented
        somewhere.
 
-* Using enums instead of int for tokens.
-Paul suggests:
-
-   #ifndef YYTOKENTYPE
-   # if defined (__STDC__) || defined (__cplusplus)
-      /* Put the tokens into the symbol table, so that GDB and other debuggers
-         know about them.  */
-      enum yytokentype {
-        FOO = 256,
-        BAR,
-        ...
-      };
-      /* POSIX requires `int' for tokens in interfaces.  */
-   #  define YYTOKENTYPE int
-   # endif
-   #endif
-   #define FOO 256
-   #define BAR 257
-   ...
-
 * Output directory
 Akim:
 
Index: data/bison.c++
===================================================================
RCS file: /cvsroot/bison/bison/data/bison.c++,v
retrieving revision 1.26
diff -u -u -r1.26 bison.c++
--- data/bison.c++ 2 May 2002 16:43:00 -0000 1.26
+++ data/bison.c++ 3 May 2002 08:40:20 -0000
@@ -50,8 +50,8 @@
 [location_stack_@<:@m4_eval([$1 - $2])@:>@])
 
 
-# b4_token_defines(TOKEN-NAME, TOKEN-NUMBER)
-# ------------------------------------------
+# b4_token_define(TOKEN-NAME, TOKEN-NUMBER)
+# -----------------------------------------
 # Output the definition of this token as #define.
 m4_define([b4_token_define],
 [#define $1 $2
Index: data/bison.simple
===================================================================
RCS file: /cvsroot/bison/bison/data/bison.simple,v
retrieving revision 1.19
diff -u -u -r1.19 bison.simple
--- data/bison.simple 2 May 2002 16:40:54 -0000 1.19
+++ data/bison.simple 3 May 2002 08:40:20 -0000
@@ -70,19 +70,39 @@
                                 [[^ABCDEFGHIJKLMNOPQRSTUVWXYZ]], [_])])
 
 
-# b4_token_defines(TOKEN-NAME, TOKEN-NUMBER)
-# ------------------------------------------
+# b4_token_define(TOKEN-NAME, TOKEN-NUMBER)
+# -----------------------------------------
 # Output the definition of this token as #define.
 m4_define([b4_token_define],
 [#define $1 $2
 ])
 
 
+# b4_token_enum(TOKEN-NAME, TOKEN-NUMBER)
+# ---------------------------------------
+# Output the definition of this token as an enum.
+m4_define([b4_token_enum],
+[enum $1 = $2])
+
+
 # b4_token_defines(LIST-OF-PAIRS-TOKEN-NAME-TOKEN-NUMBER)
 # -------------------------------------------------------
 # Output the definition of the tokens as #define.
 m4_define([b4_token_defines],
-[m4_map([b4_token_define], address@hidden)])
+[#ifndef YYTOKENTYPE
+# if defined (__STDC__) || defined (__cplusplus)
+   /* Put the tokens into the symbol table, so that GDB and other debuggers
+      know about them.  */
+   enum yytokentype {
+m4_map_sep([     b4_token_enum], [,
+],
+           address@hidden)
+   };
+   /* POSIX requires `int' for tokens in interfaces.  */
+#  define YYTOKENTYPE int
+# endif
+#endif
+m4_map([b4_token_define], address@hidden)])
 
 
 m4_divert(0)dnl
Index: src/output.c
===================================================================
RCS file: /cvsroot/bison/bison/src/output.c,v
retrieving revision 1.149
diff -u -u -r1.149 output.c
--- src/output.c 2 May 2002 15:06:46 -0000 1.149
+++ src/output.c 3 May 2002 08:40:20 -0000
@@ -603,7 +603,7 @@
       if (strchr (symbol->tag, '.') || strchr (symbol->tag, '$'))
        continue;
 
-      fprintf (out, "%s  [[[%s]], [%d]]",
+      fprintf (out, "%s[[[%s]], [%d]]",
               first ? "" : ",\n", symbol->tag, number);
       first = 0;
     }