Re: EOF redefinition (3.5->3.6 error)

[Akim Demaille]

Hi Egor,

Thanks for the report!

> Le 11 juin 2020 à 17:15, Egor Pugin <egor.pugin@gmail.com> a écrit :
> 
> The reason:
> At the end of bison generated header there is
> #undef EOQ
> #define EOQ yy_range::parser::token::EOQ

I'm sorry about this :(  These directives are made at the wrong place, they are 
"too visible". I've addressed that below.

> Possible solutions for me:
> 1) #undef EOQ in flex file again (after bison undef)

This is the right fix.

> 2) Rewrite line from return MAKE(EOQ); to return EOQ;

No, don't do that.  Currently glr.cc being simply a wrapper around glr.c, we 
have to expose the C++ names to the C parser, so you should not depend on these 
names.  The good news is that the rewriting of glr.cc is not stuck, Valentin 
made progress.  I intend to have the rewriting be the focus of 3.8, once we are 
done with Vincent's work for 3.7.

Egor, could you please check that the appended commit does fix the issue for 
you?  For convenience, you can find a packaged bison here:

https://www.lrde.epita.fr/~akim/private/bison/bison-3.6.3.2-b299e.tar.gz
https://www.lrde.epita.fr/~akim/private/bison/bison-3.6.3.2-b299e.tar.xz

Thanks in advance!

Cheers!

commit b299ea47859395be3001c9d924f5534d866805ae
Author: Akim Demaille <akim.demaille@gmail.com>
Date:   Fri Jun 12 07:28:05 2020 +0200

    glr.cc: don't leak glr.c/glr.cc scaffolding to the user
    
    Until we have a decent reimplementation of glr.cc, we have to use
    tricks to shoehorn C++ symbols to the C engine of glr.c.  Some of them
    are done via #define.  Unfortunately in Bison 3.6 some of these we
    done in the header file, which broke valid user code.
    
    Reported by Egor Pugin.
    https://lists.gnu.org/r/bug-bison/2020-06/msg00003.html
    
    * data/skeletons/glr.cc: Stop playing tricks with b4_pre_epilogue.
    (b4_glr_cc_setup, b4_glr_cc_cleanup): New.
    Much cleaner way to instal glr.cc's scaffolding around glr.c.
    * data/skeletons/glr.c: Adjust to use them.

diff --git a/TODO b/TODO
index 56608dd9..a41aa4b7 100644
--- a/TODO
+++ b/TODO
@@ -1,4 +1,7 @@
 * Bison 3.7
+** glr.cc
+Get rid of global_tokens_and_yystype.
+
 ** Bistromathic
 - Hitting tab on a line with a syntax error is ugly
 
@@ -148,6 +151,9 @@ Les catégories d'avertissements incluent :
 Line -1 and -3 should mention CATEGORIE, not CATEGORY.
 
 * Bison 3.8
+** Rewrite glr.cc
+Get rid of scaffolding in glr.c.
+
 ** Unit rules / Injection rules (Akim Demaille)
 Maybe we could expand unit rules (or "injections", see
 https://homepages.cwi.nl/~daybuild/daily-books/syntax/2-sdf/sdf.html), i.e.,
diff --git a/data/skeletons/glr.c b/data/skeletons/glr.c
index c5074a3e..76d7327b 100644
--- a/data/skeletons/glr.c
+++ b/data/skeletons/glr.c
@@ -230,7 +230,9 @@ b4_copyright([Skeleton implementation for Bison GLR parsers 
in C],
 
 ]b4_defines_if([[#include "@basename(]b4_spec_header_file[@)"]],
                [b4_shared_declarations])[
-]b4_declare_symbol_enum[
+
+]b4_glr_cc_if([b4_glr_cc_setup],
+              [b4_declare_symbol_enum])[
 
 /* Default (constant) value used for initialization for null
    right-hand sides.  Unlike the standard yacc.c template, here we set
@@ -2731,7 +2733,7 @@ m4_if(b4_prefix, [yy], [],
 #define yynerrs ]b4_prefix[nerrs]b4_locations_if([[
 #define yylloc  ]b4_prefix[lloc]])])[
 
-]m4_ifdef([b4_pre_epilogue], [b4_pre_epilogue])[]dnl This is a hack for 
glr.cc.  To remove when we have a better glr.cc.
-b4_percent_code_get([[epilogue]])[]dnl
+]b4_glr_cc_if([b4_glr_cc_cleanup])[
+]b4_percent_code_get([[epilogue]])[]dnl
 b4_epilogue[]dnl
 b4_output_end
diff --git a/data/skeletons/glr.cc b/data/skeletons/glr.cc
index 95053a2f..658b9f20 100644
--- a/data/skeletons/glr.cc
+++ b/data/skeletons/glr.cc
@@ -105,12 +105,6 @@ yyerror (]b4_locations_if([[const 
]b4_namespace_ref::b4_parser_class[::location_
          ]])[]m4_ifset([b4_parse_param], [b4_formals(b4_parse_param),
          ])[const char* msg);]])[
 
-]b4_percent_define_flag_if([[global_tokens_and_yystype]], [],
-[m4_define([b4_pre_epilogue],
-[[/* The user is using the C++ token kind, not the C one. */
-#undef ]b4_symbol(0, [id])
-])])[
-
 # Hijack the epilogue to define implementations (yyerror, parser member
 # functions etc.).
 ]m4_append([b4_epilogue],
@@ -222,6 +216,53 @@ b4_namespace_close[]dnl
 ])
 
 
+# b4_glr_cc_setup
+# ---------------
+# Setup redirections for glr.c: Map the names used in c.m4 to the ones used
+# in c++.m4.
+m4_define([b4_glr_cc_setup],
+[[#undef ]b4_symbol(-2, [id])[
+#define ]b4_symbol(-2, [id])[ 
]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(-2, [id])[
+#undef ]b4_symbol(0, [id])[
+#define ]b4_symbol(0, [id])[ 
]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(0, [id])[
+#undef ]b4_symbol(1, [id])[
+#define ]b4_symbol(1, [id])[ 
]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(1, [id])[
+
+#ifndef ]b4_api_PREFIX[STYPE
+# define ]b4_api_PREFIX[STYPE 
]b4_namespace_ref[::]b4_parser_class[::semantic_type
+#endif
+#ifndef ]b4_api_PREFIX[LTYPE
+# define ]b4_api_PREFIX[LTYPE 
]b4_namespace_ref[::]b4_parser_class[::location_type
+#endif
+
+typedef ]b4_namespace_ref[::]b4_parser_class[::symbol_kind_type 
yysymbol_kind_t;
+#define ]b4_symbol_prefix[YYEMPTY  
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEMPTY
+#define ]b4_symbol_prefix[YYerror  
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYerror
+#define ]b4_symbol_prefix[YYEOF    
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEOF
+#define ]b4_symbol_prefix[YYUNDEF  
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYUNDEF
+]])
+
+
+# b4_glr_cc_cleanup
+# -----------------
+# Remove redirections for glr.c.
+m4_define([b4_glr_cc_cleanup],
+[b4_percent_define_flag_if([[global_tokens_and_yystype]], [],
+[[#undef ]b4_symbol(-2, [id])[
+#undef ]b4_symbol(0, [id])[
+#undef ]b4_symbol(1, [id])[
+]])[
+
+#undef ]b4_api_PREFIX[STYPE
+#undef ]b4_api_PREFIX[LTYPE
+
+#undef ]b4_symbol_prefix[YYEMPTY
+#undef ]b4_symbol_prefix[YYerror
+#undef ]b4_symbol_prefix[YYEOF
+#undef ]b4_symbol_prefix[YYUNDEF
+]])
+
+
 # b4_shared_declarations(hh|cc)
 # -----------------------------
 # Declaration that might either go into the header (if --defines, $1 = hh)
@@ -339,33 +380,11 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],
 ])[
 ]b4_namespace_close[
 
-]dnl Map the name used in c.m4 to the one used in c++.m4.
-[#undef ]b4_symbol(-2, [id])[
-#define ]b4_symbol(-2, [id])[ 
]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(-2, [id])[
-#undef ]b4_symbol(0, [id])[
-#define ]b4_symbol(0, [id])[ 
]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(0, [id])[
-#undef ]b4_symbol(1, [id])[
-#define ]b4_symbol(1, [id])[ 
]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(1, [id])[
-
-#ifndef ]b4_api_PREFIX[STYPE
-# define ]b4_api_PREFIX[STYPE 
]b4_namespace_ref[::]b4_parser_class[::semantic_type
-#endif
-#ifndef ]b4_api_PREFIX[LTYPE
-# define ]b4_api_PREFIX[LTYPE 
]b4_namespace_ref[::]b4_parser_class[::location_type
-#endif
-
-]m4_define([b4_declare_symbol_enum],
-[[typedef ]b4_namespace_ref[::]b4_parser_class[::symbol_kind_type 
yysymbol_kind_t;
-#define ]b4_symbol_prefix[YYEMPTY  
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEMPTY
-#define ]b4_symbol_prefix[YYerror  
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYerror
-#define ]b4_symbol_prefix[YYEOF    
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEOF
-#define ]b4_symbol_prefix[YYUNDEF  
]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYUNDEF
-]])[
 ]b4_percent_code_get([[provides]])[
 ]m4_popdef([b4_parse_param])dnl
-])
+])[
 
-b4_defines_if(
+]b4_defines_if(
 [b4_output_begin([b4_spec_header_file])
 b4_copyright([Skeleton interface for Bison GLR parsers in C++],
              [2002-2015, 2018-2020])[