Merge branch 'maint'

[bison.git] / data / c.m4

diff --git a/data/c.m4 b/data/c.m4
index 1fe4bc56c74d22f86a93dac51412a78034767cba..a07422d1eba14282863218e40024c96bef0f2f9d 100644 (file)
--- a/data/c.m4
+++ b/data/c.m4
@@ -1,8 +1,8 @@
                                                             -*- Autoconf -*-
 
 # C M4 Macros for Bison.
                                                             -*- Autoconf -*-
 
 # C M4 Macros for Bison.

-# Copyright (C) 2002, 2004, 2005, 2006, 2007, 2008 Free Software
-# Foundation, Inc.
+
+# Copyright (C) 2002, 2004-2012 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
 
 # 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


@@ -17,21 +17,72 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 

+m4_include(b4_pkgdatadir/[c-like.m4])
+
+# b4_tocpp(STRING)
+# ----------------
+# Convert STRING into a valid C macro name.
+m4_define([b4_tocpp],
+[m4_toupper(m4_bpatsubst(m4_quote($1), [[^a-zA-Z0-9]+], [_]))])
+
+
+# b4_cpp_guard(FILE)
+# ------------------
+# A valid C macro name to use as a CPP header guard for FILE.
+m4_define([b4_cpp_guard],
+[b4_tocpp(m4_defn([b4_prefix])/[$1])])
+
+
+# b4_cpp_guard_open(FILE)
+# b4_cpp_guard_close(FILE)
+# ------------------------
+# Open/close CPP inclusion guards for FILE.
+m4_define([b4_cpp_guard_open],
+[#ifndef b4_cpp_guard([$1])
+# define b4_cpp_guard([$1])])
+
+m4_define([b4_cpp_guard_close],
+[#endif b4_comment([!b4_cpp_guard([$1])])])
+
+

 ## ---------------- ##
 ## Identification.  ##
 ## ---------------- ##
 
 ## ---------------- ##
 ## Identification.  ##
 ## ---------------- ##
 

-# b4_comment(TEXT)
-# ----------------
-m4_define([b4_comment], [/* m4_bpatsubst([$1], [
-], [
-   ])  */])
+# b4_comment_(TEXT, OPEN, CONTINUE, END)
+# -------------------------------------
+# Put TEXT in comment.  Avoid trailing spaces: don't indent empty lines.
+# Avoid adding indentation to the first line, as the indentation comes
+# from OPEN.  That's why we don't patsubst([$1], [^\(.\)], [   \1]).
+#
+# Prefix all the output lines with PREFIX.
+m4_define([b4_comment_], [$2[]m4_bpatsubst([$1], [
+\(.\)], [
+$3\1])$4])
+
+
+# b4_c_comment(TEXT, [PREFIX])
+# ----------------------------
+# Put TEXT in comment.  Avoid trailing spaces: don't indent empty lines.
+# Avoid adding indentation to the first line, as the indentation comes
+# from "/*".  That's why we don't patsubst([$1], [^\(.\)], [   \1]).
+#
+# Prefix all the output lines with PREFIX.
+m4_define([b4_c_comment],
+[b4_comment_([$1], [$2/* ], [$2   ], [$2  */])])
+
+
+# b4_comment(TEXT, [PREFIX])
+# --------------------------
+# By default, C comments.
+m4_define([b4_comment], [b4_c_comment($@)])
+

 
 # b4_identification
 # -----------------
 # Depends on individual skeletons to define b4_pure_flag, b4_push_flag, or
 # b4_pull_flag if they use the values of the %define variables api.pure or
 
 # b4_identification
 # -----------------
 # Depends on individual skeletons to define b4_pure_flag, b4_push_flag, or
 # b4_pull_flag if they use the values of the %define variables api.pure or

-# api.push_pull.
+# api.push-pull.

 m4_define([b4_identification],
 [[/* Identify Bison output.  */
 #define YYBISON 1
 m4_define([b4_identification],
 [[/* Identify Bison output.  */
 #define YYBISON 1


@@ -50,9 +101,6 @@ m4_define([b4_identification],
 
 /* Pull parsers.  */
 #define YYPULL ]b4_pull_flag])[
 
 /* Pull parsers.  */
 #define YYPULL ]b4_pull_flag])[

-
-/* Using locations.  */
-#define YYLSP_NEEDED ]b4_locations_flag[

 ]])
 
 
 ]])
 
 


@@ -60,11 +108,24 @@ m4_define([b4_identification],
 ## Default values.  ##
 ## ---------------- ##
 
 ## Default values.  ##
 ## ---------------- ##
 

+# b4_api_prefix, b4_api_PREFIX
+# ----------------------------
+# Corresponds to %define api.prefix
+b4_percent_define_default([[api.prefix]], [[yy]])
+m4_define([b4_api_prefix],
+[b4_percent_define_get([[api.prefix]])])
+m4_define([b4_api_PREFIX],
+[m4_toupper(b4_api_prefix)])
+
+
+# b4_prefix
+# ---------
+# If the %name-prefix is not given, it is api.prefix.
+m4_define_default([b4_prefix], [b4_api_prefix])
+

 # If the %union is not named, its name is YYSTYPE.
 # If the %union is not named, its name is YYSTYPE.

-m4_define_default([b4_union_name], [YYSTYPE])
+m4_define_default([b4_union_name], [b4_api_PREFIX[]STYPE])

 
 

-# If the %name-prefix is not given, it is yy.
-m4_define_default([b4_prefix], [yy])

 
 ## ------------------------ ##
 ## Pure/impure interfaces.  ##
 
 ## ------------------------ ##
 ## Pure/impure interfaces.  ##


@@ -97,11 +158,13 @@ m4_popdef([$2])dnl
 m4_popdef([$1])dnl
 ])])
 
 m4_popdef([$1])dnl
 ])])
 

-# b4_parse_param_use
-# ------------------
-# `YYUSE' all the parse-params.
+# b4_parse_param_use([VAL], [LOC])
+# --------------------------------
+# `YYUSE' VAL, LOC if locations are enabled, and all the parse-params.

 m4_define([b4_parse_param_use],
 m4_define([b4_parse_param_use],

-[b4_parse_param_for([Decl], [Formal], [  YYUSE (Formal);
+[m4_ifvaln([$1], [  YYUSE([$1]);])dnl
+b4_locations_if([m4_ifvaln([$2], [  YYUSE ([$2]);])])dnl
+b4_parse_param_for([Decl], [Formal], [  YYUSE (Formal);

 ])dnl
 ])
 
 ])dnl
 ])
 


@@ -123,7 +186,7 @@ m4_define([b4_int_type],
 
        m4_eval([0 <= $1]),                [1], [unsigned int],
 
 
        m4_eval([0 <= $1]),                [1], [unsigned int],
 

-                                              [int])])
+                                               [int])])

 
 
 # b4_int_type_for(NAME)
 
 
 # b4_int_type_for(NAME)


@@ -134,75 +197,123 @@ m4_define([b4_int_type_for],
 [b4_int_type($1_min, $1_max)])
 
 
 [b4_int_type($1_min, $1_max)])
 
 

+# b4_table_value_equals(TABLE, VALUE, LITERAL)
+# --------------------------------------------
+# Without inducing a comparison warning from the compiler, check if the
+# literal value LITERAL equals VALUE from table TABLE, which must have
+# TABLE_min and TABLE_max defined.  YYID must be defined as an identity
+# function that suppresses warnings about constant conditions.
+m4_define([b4_table_value_equals],
+[m4_if(m4_eval($3 < m4_indir([b4_]$1[_min])
+               || m4_indir([b4_]$1[_max]) < $3), [1],
+       [[YYID (0)]],
+       [[((]$2[) == (]$3[))]])])
+

 
 ## ---------##
 ## Values.  ##
 ## ---------##
 
 
 ## ---------##
 ## Values.  ##
 ## ---------##
 

-# b4_null
----------
-# Return a null pointer constant.  NULL infringes on the user name
-# space in C, so use 0 rather than NULL.
-m4_define([b4_null], [0])

 
 

+# b4_null_define
+# --------------
+# Portability issues: define a YY_NULL appropriate for the current
+# language (C, C++98, or C++11).
+m4_define([b4_null_define],
+[# ifndef YY_NULL
+#  if defined __cplusplus && 201103L <= __cplusplus
+#   define YY_NULL nullptr
+#  else
+#   define YY_NULL 0
+#  endif
+# endif[]dnl
+])

 
 
 
 

+# b4_null
+# -------
+# Return a null pointer constant.
+m4_define([b4_null], [YY_NULL])
+
+# b4_integral_parser_table_define(TABLE-NAME, CONTENT, COMMENT)
+# -------------------------------------------------------------
+# Define "yy<TABLE-NAME>" which contents is CONTENT.
+m4_define([b4_integral_parser_table_define],
+[m4_ifvaln([$3], [b4_c_comment([$3], [  ])])dnl
+static const b4_int_type_for([$2]) yy$1[[]] =
+{
+  $2
+};dnl
+])
+

 
 ## ------------------------- ##
 ## Assigning token numbers.  ##
 ## ------------------------- ##
 
 
 ## ------------------------- ##
 ## Assigning token numbers.  ##
 ## ------------------------- ##
 

-# b4_token_define(TOKEN-NAME, TOKEN-NUMBER)
-# -----------------------------------------
+# b4_token_define(TOKEN-NUM)
+# --------------------------

 # Output the definition of this token as #define.
 m4_define([b4_token_define],
 # Output the definition of this token as #define.
 m4_define([b4_token_define],

-[#define $1 $2
-])
+[b4_token_format([#define %s %s], [$1])])

 
 

-
-# b4_token_defines(LIST-OF-PAIRS-TOKEN-NAME-TOKEN-NUMBER)
-# -------------------------------------------------------
-# Output the definition of the tokens (if there are) as #defines.
+# b4_token_defines
+# ----------------
+# Output the definition of the tokens.

 m4_define([b4_token_defines],
 m4_define([b4_token_defines],

-[m4_if([$#$1], [1], [],
-[/* Tokens.  */
-m4_map([b4_token_define], [$@])])
-])
+[b4_any_token_visible_if([/* Tokens.  */
+m4_join([
+], b4_symbol_map([b4_token_define]))
+])])

 
 
 
 

-# b4_token_enum(TOKEN-NAME, TOKEN-NUMBER)
-# ---------------------------------------
+# b4_token_enum(TOKEN-NUM)
+# ------------------------

 # Output the definition of this token as an enum.
 m4_define([b4_token_enum],
 # Output the definition of this token as an enum.
 m4_define([b4_token_enum],

-[$1 = $2])
+[b4_token_format([%s = %s], [$1])])

 
 
 
 

-# b4_token_enums(LIST-OF-PAIRS-TOKEN-NAME-TOKEN-NUMBER)
-# -----------------------------------------------------
+# b4_token_enums
+# --------------

 # Output the definition of the tokens (if there are) as enums.
 m4_define([b4_token_enums],
 # Output the definition of the tokens (if there are) as enums.
 m4_define([b4_token_enums],

-[m4_if([$#$1], [1], [],
-[/* Tokens.  */
-#ifndef YYTOKENTYPE
-# define YYTOKENTYPE
-   /* Put the tokens into the symbol table, so that GDB and other debuggers
-      know about them.  */
-   enum yytokentype {
-m4_map_sep([     b4_token_enum], [,
-],
-          [$@])
-   };
+[b4_any_token_visible_if([[/* Tokens.  */
+#ifndef ]b4_api_PREFIX[TOKENTYPE
+# define ]b4_api_PREFIX[TOKENTYPE
+  /* Put the tokens into the symbol table, so that GDB and other debuggers
+     know about them.  */
+  enum ]b4_api_prefix[tokentype
+  {
+    ]m4_join([,
+    ],
+             b4_symbol_map([b4_token_enum]))[
+  };

 #endif
 #endif

-])])
+]])])

 
 
 
 

-# b4_token_enums_defines(LIST-OF-PAIRS-TOKEN-NAME-TOKEN-NUMBER)
-# -------------------------------------------------------------
-# Output the definition of the tokens (if there are any) as enums and, if POSIX
-# Yacc is enabled, as #defines.
+# b4_token_enums_defines
+# ----------------------
+# Output the definition of the tokens (if there are any) as enums and,
+# if POSIX Yacc is enabled, as #defines.

 m4_define([b4_token_enums_defines],
 m4_define([b4_token_enums_defines],

-[b4_token_enums($@)b4_yacc_if([b4_token_defines($@)], [])
-])
+[b4_token_enums[]b4_yacc_if([b4_token_defines])])
+
+
+## ----------------- ##
+## Semantic Values.  ##
+## ----------------- ##
+
+
+# b4_symbol_value(VAL, [TYPE])
+# ----------------------------
+# Given a semantic value VAL ($$, $1 etc.), extract its value of type
+# TYPE if TYPE is given, otherwise just return VAL.  The result can be
+# used safetly, it is put in parens to avoid nasty precedence issues.
+# TYPE is *not* put in braces, provide some if needed.
+m4_define([b4_symbol_value],
+[($1[]m4_ifval([$2], [.$2]))])

 
 
 
 
 
 


@@ -254,7 +365,7 @@ $1 (b4_c_ansi_formals(m4_shift2($@)))[]dnl
 m4_define([b4_c_ansi_formals],
 [m4_if([$#], [0], [void],
        [$#$1], [1], [void],
 m4_define([b4_c_ansi_formals],
 [m4_if([$#], [0], [void],
        [$#$1], [1], [void],

-              [m4_map_sep([b4_c_ansi_formal], [, ], [$@])])])
+               [m4_map_sep([b4_c_ansi_formal], [, ], [$@])])])

 
 m4_define([b4_c_ansi_formal],
 [$1])
 
 m4_define([b4_c_ansi_formal],
 [$1])


@@ -275,9 +386,9 @@ m4_define([b4_c_knr_formal_name],
 # Output the K&R argument declarations.
 m4_define([b4_c_knr_formal_decls],
 [m4_map_sep([b4_c_knr_formal_decl],
 # Output the K&R argument declarations.
 m4_define([b4_c_knr_formal_decls],
 [m4_map_sep([b4_c_knr_formal_decl],

-           [
+            [

 ],
 ],

-           [$@])])
+            [$@])])

 
 m4_define([b4_c_knr_formal_decl],
 [    $1;])
 
 m4_define([b4_c_knr_formal_decl],
 [    $1;])


@@ -293,7 +404,7 @@ m4_define([b4_c_knr_formal_decl],
 # -----------------------------------------------------------
 # Declare the function NAME.
 m4_define([b4_c_function_decl],
 # -----------------------------------------------------------
 # Declare the function NAME.
 m4_define([b4_c_function_decl],

-[#if defined __STDC__ || defined __cplusplus
+[#if b4_c_modern

 b4_c_ansi_function_decl($@)
 #else
 $2 $1 ();
 b4_c_ansi_function_decl($@)
 #else
 $2 $1 ();


@@ -352,24 +463,17 @@ m4_define([b4_sync_start], [[#]line $1 $2])
 m4_define([b4_case],
 [  case $1:
 $2
 m4_define([b4_case],
 [  case $1:
 $2

+b4_syncline([@oline@], [@ofile@])

     break;])
 
     break;])
 

-# b4_symbol_actions(FILENAME, LINENO,
-#                   SYMBOL-TAG, SYMBOL-NUM,
-#                   SYMBOL-ACTION, SYMBOL-TYPENAME)
-# -------------------------------------------------
-m4_define([b4_symbol_actions],
-[m4_pushdef([b4_dollar_dollar],
-   [m4_ifval([$6], [(yyvaluep->$6)], [(*yyvaluep)])])dnl
-m4_pushdef([b4_at_dollar], [(*yylocationp)])dnl
-      case $4: /* $3 */
-b4_syncline([$2], [$1])
-       $5;
+
+# b4_predicate_case(LABEL, CONDITIONS)
+# ------------------------------------
+m4_define([b4_predicate_case],
+[  case $1:
+    if (! ($2)) YYERROR;

 b4_syncline([@oline@], [@ofile@])
 b4_syncline([@oline@], [@ofile@])

-       break;
-m4_popdef([b4_at_dollar])dnl
-m4_popdef([b4_dollar_dollar])dnl
-])
+    break;])

 
 
 # b4_yydestruct_generate(FUNCTION-DECLARATOR)
 
 
 # b4_yydestruct_generate(FUNCTION-DECLARATOR)


@@ -391,20 +495,16 @@ m4_define_default([b4_yydestruct_generate],
 b4_locations_if(            [, [[YYLTYPE *yylocationp], [yylocationp]]])[]dnl
 m4_ifset([b4_parse_param], [, b4_parse_param]))[
 {
 b4_locations_if(            [, [[YYLTYPE *yylocationp], [yylocationp]]])[]dnl
 m4_ifset([b4_parse_param], [, b4_parse_param]))[
 {

-  YYUSE (yyvaluep);
-]b4_locations_if([  YYUSE (yylocationp);
-])dnl
-b4_parse_param_use[]dnl
-[
-  if (!yymsg)
+]b4_parse_param_use([yyvaluep], [yylocationp])dnl
+[  if (!yymsg)

     yymsg = "Deleting";
   YY_SYMBOL_PRINT (yymsg, yytype, yyvaluep, yylocationp);
 
   switch (yytype)
     {
     yymsg = "Deleting";
   YY_SYMBOL_PRINT (yymsg, yytype, yyvaluep, yylocationp);
 
   switch (yytype)
     {

-]m4_map([b4_symbol_actions], m4_defn([b4_symbol_destructors]))[
-      default:
-       break;
+]b4_symbol_foreach([b4_symbol_destructor])dnl
+[      default:
+        break;

     }
 }]dnl
 ])
     }
 }]dnl
 ])


@@ -424,28 +524,28 @@ m4_define_default([b4_yy_symbol_print_generate],
 /*ARGSUSED*/
 ]$1([yy_symbol_value_print],
     [static void],
 /*ARGSUSED*/
 ]$1([yy_symbol_value_print],
     [static void],

-              [[FILE *yyoutput],                       [yyoutput]],
-              [[int yytype],                           [yytype]],
-              [[YYSTYPE const * const yyvaluep],       [yyvaluep]][]dnl
+               [[FILE *yyoutput],                       [yyoutput]],
+               [[int yytype],                           [yytype]],
+               [[YYSTYPE const * const yyvaluep],       [yyvaluep]][]dnl

 b4_locations_if([, [[YYLTYPE const * const yylocationp], [yylocationp]]])[]dnl
 m4_ifset([b4_parse_param], [, b4_parse_param]))[
 {
 b4_locations_if([, [[YYLTYPE const * const yylocationp], [yylocationp]]])[]dnl
 m4_ifset([b4_parse_param], [, b4_parse_param]))[
 {

-  if (!yyvaluep)
-    return;
-]b4_locations_if([  YYUSE (yylocationp);
-])dnl
-b4_parse_param_use[]dnl
-[# ifdef YYPRINT
+  FILE *yyo = yyoutput;
+]b4_parse_param_use([yyo], [yylocationp])dnl
+[  if (!yyvaluep)
+    return;]
+dnl glr.c does not feature yytoknum.
+m4_if(b4_skeleton, ["yacc.c"],
+[[# ifdef YYPRINT

   if (yytype < YYNTOKENS)
     YYPRINT (yyoutput, yytoknum[yytype], *yyvaluep);
   if (yytype < YYNTOKENS)
     YYPRINT (yyoutput, yytoknum[yytype], *yyvaluep);

-# else
-  YYUSE (yyoutput);

 # endif
 # endif

-  switch (yytype)
+]])dnl
+[  switch (yytype)

     {
     {

-]m4_map([b4_symbol_actions], m4_defn([b4_symbol_printers]))dnl
+]b4_symbol_foreach([b4_symbol_printer])dnl

 [      default:
 [      default:

-       break;
+        break;

     }
 }
 
     }
 }
 


@@ -456,9 +556,9 @@ b4_parse_param_use[]dnl
 
 ]$1([yy_symbol_print],
     [static void],
 
 ]$1([yy_symbol_print],
     [static void],

-              [[FILE *yyoutput],                       [yyoutput]],
-              [[int yytype],                           [yytype]],
-              [[YYSTYPE const * const yyvaluep],       [yyvaluep]][]dnl
+               [[FILE *yyoutput],                       [yyoutput]],
+               [[int yytype],                           [yytype]],
+               [[YYSTYPE const * const yyvaluep],       [yyvaluep]][]dnl

 b4_locations_if([, [[YYLTYPE const * const yylocationp], [yylocationp]]])[]dnl
 m4_ifset([b4_parse_param], [, b4_parse_param]))[
 {
 b4_locations_if([, [[YYLTYPE const * const yylocationp], [yylocationp]]])[]dnl
 m4_ifset([b4_parse_param], [, b4_parse_param]))[
 {


@@ -475,3 +575,100 @@ b4_locations_if([, yylocationp])[]b4_user_args[);
   YYFPRINTF (yyoutput, ")");
 }]dnl
 ])
   YYFPRINTF (yyoutput, ")");
 }]dnl
 ])

+
+## -------------- ##
+## Declarations.  ##
+## -------------- ##
+
+# b4_declare_yylstype
+# -------------------
+# Declarations that might either go into the header (if --defines) or
+# in the parser body.  Declare YYSTYPE/YYLTYPE, and yylval/yylloc.
+m4_define([b4_declare_yylstype],
+[[#if ! defined ]b4_api_PREFIX[STYPE && ! defined ]b4_api_PREFIX[STYPE_IS_DECLARED
+]m4_ifdef([b4_stype],
+[[typedef union ]b4_union_name[
+{
+]b4_user_stype[
+} ]b4_api_PREFIX[STYPE;
+# define ]b4_api_PREFIX[STYPE_IS_TRIVIAL 1]],
+[m4_if(b4_tag_seen_flag, 0,
+[[typedef int ]b4_api_PREFIX[STYPE;
+# define ]b4_api_PREFIX[STYPE_IS_TRIVIAL 1]])])[
+# define ]b4_api_PREFIX[STYPE_IS_DECLARED 1
+#endif]b4_locations_if([[
+
+#if ! defined ]b4_api_PREFIX[LTYPE && ! defined ]b4_api_PREFIX[LTYPE_IS_DECLARED
+typedef struct ]b4_api_PREFIX[LTYPE
+{
+  int first_line;
+  int first_column;
+  int last_line;
+  int last_column;
+} ]b4_api_PREFIX[LTYPE;
+# define ]b4_api_PREFIX[LTYPE_IS_DECLARED 1
+# define ]b4_api_PREFIX[LTYPE_IS_TRIVIAL 1
+#endif]])
+
+b4_pure_if([], [[extern ]b4_api_PREFIX[STYPE ]b4_prefix[lval;
+]b4_locations_if([[extern ]b4_api_PREFIX[LTYPE ]b4_prefix[lloc;]])])[]dnl
+])
+
+# b4_YYDEBUG_define
+# ------------------
+m4_define([b4_YYDEBUG_define],
+[[/* Enabling traces.  */
+]m4_if(b4_api_prefix, [yy],
+[[#ifndef YYDEBUG
+# define YYDEBUG ]b4_parse_trace_if([1], [0])[
+#endif]],
+[[#ifndef ]b4_api_PREFIX[DEBUG
+# if defined YYDEBUG
+#if YYDEBUG
+#   define ]b4_api_PREFIX[DEBUG 1
+#  else
+#   define ]b4_api_PREFIX[DEBUG 0
+#  endif
+# else /* ! defined YYDEBUG */
+#  define ]b4_api_PREFIX[DEBUG ]b4_parse_trace_if([1], [0])[
+# endif /* ! defined ]b4_api_PREFIX[DEBUG */
+#endif  /* ! defined ]b4_api_PREFIX[DEBUG */]])[]dnl
+])
+
+# b4_declare_yydebug
+# ------------------
+m4_define([b4_declare_yydebug],
+[b4_YYDEBUG_define[
+#if ]b4_api_PREFIX[DEBUG
+extern int ]b4_prefix[debug;
+#endif][]dnl
+])
+
+# b4_yylloc_default_define
+# ------------------------
+# Define YYLLOC_DEFAULT.
+m4_define([b4_yylloc_default_define],
+[[/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].
+   If N is 0, then set CURRENT to the empty location which ends
+   the previous symbol: RHS[0] (always defined).  */
+
+#ifndef YYLLOC_DEFAULT
+# define YYLLOC_DEFAULT(Current, Rhs, N)                                \
+    do                                                                  \
+      if (YYID (N))                                                     \
+        {                                                               \
+          (Current).first_line   = YYRHSLOC (Rhs, 1).first_line;        \
+          (Current).first_column = YYRHSLOC (Rhs, 1).first_column;      \
+          (Current).last_line    = YYRHSLOC (Rhs, N).last_line;         \
+          (Current).last_column  = YYRHSLOC (Rhs, N).last_column;       \
+        }                                                               \
+      else                                                              \
+        {                                                               \
+          (Current).first_line   = (Current).last_line   =              \
+            YYRHSLOC (Rhs, 0).last_line;                                \
+          (Current).first_column = (Current).last_column =              \
+            YYRHSLOC (Rhs, 0).last_column;                              \
+        }                                                               \
+    while (YYID (0))
+#endif
+]])