bison parse-gram.y union

[Paul Eggert]

(I installed this patch on Jan 3 but forgot to mention it on this
list.  Sorry.  Here's a belated report.  The NEWS and doc fixes have
already been reported.)

twlevo <address@hidden> writes:

> parse-gram.y line 248, multiple %union statements 
> are not detected and warned in input grammar.
>
> %union { int somenumber; }
> %union { char *somestring; }

Thanks for reporting this.  POSIX allows this in the grammar for Yacc
grammars, but it doesn't give a semantics.  Traditional yacc generates
garbage in this case.  I think a nicer thing to do is to concatenate
the union bodies, so I installed this:

2006-01-03  Paul Eggert  <address@hidden>

        * data/glr.c, data/glr.cc, data/lalr1.cc, data/yacc.c:
        Allow multiple %union directives, whose contents concatenate.
        * src/parse-gram.y (grammar_declaration): Likewise.
        Use muscle_code_grow, so that we don't need stype_line any more.
        All uses changed.

Index: data/glr.c
===================================================================
RCS file: /cvsroot/bison/bison/data/glr.c,v
retrieving revision 1.152
diff -p -u -r1.152 glr.c
--- data/glr.c  3 Jan 2006 19:12:55 -0000       1.152
+++ data/glr.c  3 Jan 2006 20:23:22 -0000
@@ -173,10 +173,11 @@ m4_define([b4_shared_declarations],
 
 #if ! defined (YYSTYPE) && ! defined (YYSTYPE_IS_DECLARED)
 ]m4_ifdef([b4_stype],
-[b4_syncline([b4_stype_line], [b4_file_name])
-typedef union m4_bregexp(b4_stype, [^{], [YYSTYPE ])b4_stype YYSTYPE;
+[typedef union m4_bregexp(b4_stype, [^{], [YYSTYPE ])
+b4_stype
 /* Line __line__ of glr.c.  */
-b4_syncline(address@hidden@], address@hidden@])],
+b4_syncline(address@hidden@], address@hidden@])
+       YYSTYPE;],
 [typedef int YYSTYPE;])[
 # define YYSTYPE_IS_DECLARED 1
 # define YYSTYPE_IS_TRIVIAL 1
Index: data/glr.cc
===================================================================
RCS file: /cvsroot/bison/bison/data/glr.cc,v
retrieving revision 1.10
diff -p -u -r1.10 glr.cc
--- data/glr.cc 3 Jan 2006 19:12:55 -0000       1.10
+++ data/glr.cc 3 Jan 2006 20:23:23 -0000
@@ -296,10 +296,11 @@ namespace yy
     /// Symbol semantic values.
 #if ! defined (YYSTYPE)
 ]m4_ifdef([b4_stype],
-[b4_syncline([b4_stype_line], [b4_file_name])
-    union semantic_type b4_stype;
+[    union semantic_type
+b4_stype
 /* Line __line__ of lalr1.cc.  */
-b4_syncline(address@hidden@], address@hidden@])],
+b4_syncline(address@hidden@], address@hidden@])
+       ;],
 [    typedef int semantic_type;])[
 #else
     typedef YYSTYPE semantic_type;
Index: data/lalr1.cc
===================================================================
RCS file: /cvsroot/bison/bison/data/lalr1.cc,v
retrieving revision 1.118
diff -p -u -r1.118 lalr1.cc
--- data/lalr1.cc       22 Dec 2005 13:01:50 -0000      1.118
+++ data/lalr1.cc       3 Jan 2006 20:23:23 -0000
@@ -2,7 +2,7 @@ m4_divert(-1)
 
 # C++ skeleton for Bison
 
-# Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+# Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -30,7 +30,7 @@ m4_divert(0)dnl
 m4_if(b4_defines_flag, 0, [],
 address@hidden @output_header_name@
 b4_copyright([C++ Skeleton parser for LALR(1) parsing with Bison],
-             [2002, 2003, 2004, 2005])
+             [2002, 2003, 2004, 2005, 2006])
 dnl FIXME: This is wrong, we want computed header guards.
 [
 /* C++ LALR(1) parser skeleton written by Akim Demaille.  */
@@ -104,10 +104,11 @@ namespace yy
     /// Symbol semantic values.
 #if ! defined (YYSTYPE)
 ]m4_ifdef([b4_stype],
-[b4_syncline([b4_stype_line], [b4_file_name])
-    union semantic_type b4_stype;
+[    union semantic_type
+b4_stype
 /* Line __line__ of lalr1.cc.  */
-b4_syncline(address@hidden@], address@hidden@])],
+b4_syncline(address@hidden@], address@hidden@])
+       ;],
 [    typedef int semantic_type;])[
 #else
     typedef YYSTYPE semantic_type;
@@ -295,7 +296,7 @@ b4_error_verbose_if([, int tok])[);
 ])dnl
 @output @output_parser_name@
 b4_copyright([C++ Skeleton parser for LALR(1) parsing with Bison],
-             [2002, 2003, 2004, 2005])
+             [2002, 2003, 2004, 2005, 2006])
 m4_if(b4_prefix[], [yy], [],
 [
 // Take the name prefix into account.
@@ -1048,7 +1049,8 @@ b4_error_verbose_if([, int tok])[)
 ]b4_epilogue
 dnl
 @output b4_dir_prefix[]stack.hh
-b4_copyright([stack handling for Bison C++ parsers], [2002, 2003, 2004, 2005])[
+b4_copyright([stack handling for Bison C++ parsers],
+  [2002, 2003, 2004, 2005, 2006])[
 
 #ifndef BISON_STACK_HH
 # define BISON_STACK_HH
Index: data/yacc.c
===================================================================
RCS file: /cvsroot/bison/bison/data/yacc.c,v
retrieving revision 1.127
diff -p -u -r1.127 yacc.c
--- data/yacc.c 3 Jan 2006 19:12:55 -0000       1.127
+++ data/yacc.c 3 Jan 2006 20:23:23 -0000
@@ -189,10 +189,11 @@ b4_location_if([#define yylloc b4_prefix
 
 #if ! defined (YYSTYPE) && ! defined (YYSTYPE_IS_DECLARED)
 ]m4_ifdef([b4_stype],
-[b4_syncline([b4_stype_line], [b4_file_name])
-typedef union m4_bregexp(b4_stype, [^{], [YYSTYPE ])b4_stype YYSTYPE;
+[typedef union m4_bregexp(b4_stype, [^{], [YYSTYPE ])
+b4_stype
 /* Line __line__ of yacc.c.  */
-b4_syncline(address@hidden@], address@hidden@])],
+b4_syncline(address@hidden@], address@hidden@])
+       YYSTYPE;],
 [typedef int YYSTYPE;])[
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
 # define YYSTYPE_IS_DECLARED 1
@@ -1508,10 +1509,11 @@ b4_token_enums_defines(b4_tokens)
 
 #if ! defined (YYSTYPE) && ! defined (YYSTYPE_IS_DECLARED)
 m4_ifdef([b4_stype],
-[b4_syncline([b4_stype_line], [b4_file_name])
-typedef union m4_bregexp(b4_stype, [^{], [YYSTYPE ])b4_stype YYSTYPE;
+[typedef union m4_bregexp(b4_stype, [^{], [YYSTYPE ])
+b4_stype
 /* Line __line__ of yacc.c.  */
-b4_syncline(address@hidden@], address@hidden@])],
+b4_syncline(address@hidden@], address@hidden@])
+       YYSTYPE;],
 [typedef int YYSTYPE;])
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
 # define YYSTYPE_IS_DECLARED 1
Index: src/parse-gram.y
===================================================================
RCS file: /cvsroot/bison/bison/src/parse-gram.y,v
retrieving revision 1.65
diff -p -u -r1.65 parse-gram.y
--- src/parse-gram.y    27 Dec 2005 17:50:00 -0000      1.65
+++ src/parse-gram.y    3 Jan 2006 20:23:23 -0000
@@ -247,9 +247,19 @@ grammar_declaration:
     }
 | "%union {...}"
     {
+      char const *body = $1;
+
+      if (typed)
+       {
+         /* Concatenate the union bodies, turning the first one's
+            trailing '}' into '\n', and omitting the second one's '{'.  */
+         char *code = muscle_find ("stype");
+         code[strlen (code) - 1] = '\n';
+         body++;
+       }
+
       typed = true;
-      MUSCLE_INSERT_INT ("stype_line", @1.start.line);
-      muscle_insert ("stype", $1);
+      muscle_code_grow ("stype", body, @1);
     }
 | "%destructor {...}" symbols.1
     {