X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/a5d80ba505eac59de1c935dae86c757d9913e2b0..96029914a688997caef26edb87aa4c2131299fed:/data/c.m4?ds=sidebyside

diff --git a/data/c.m4 b/data/c.m4
index 2ef88b15..8bd96b85 100644
--- a/data/c.m4
+++ b/data/c.m4
@@ -1,106 +1,115 @@
-m4_divert(-1)                                               -*- Autoconf -*-
+                                                            -*- Autoconf -*-
 
 # C M4 Macros for Bison.
-# Copyright (C) 2002, 2004, 2005, 2006 Free Software Foundation, Inc.
 
-# This program is free software; you can redistribute it and/or modify
+# 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
-# the Free Software Foundation; either version 2 of the License, or
+# the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
-
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
-
+#
 # You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-# 02110-1301  USA
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+m4_include(b4_pkgdatadir/[c-like.m4])
 
-## ---------------- ##
-## Identification.  ##
-## ---------------- ##
+# 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_copyright(TITLE, YEARS)
-# --------------------------
-m4_define([b4_copyright],
-[/* A Bison parser, made by GNU Bison b4_version.  */
 
-/* $1
-
-m4_text_wrap([Copyright (C) $2 Free Software Foundation, Inc.], [   ])
+# b4_cpp_guard(FILE)
+# ------------------
+# A valid C macro name to use as a CPP header guard for FILE.
+m4_define([b4_cpp_guard],
+[[YY_]b4_tocpp(m4_defn([b4_prefix])/[$1])[_INCLUDED]])
 
-   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
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
 
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
+# b4_cpp_guard_open(FILE)
+# b4_cpp_guard_close(FILE)
+# ------------------------
+# If FILE does not expand to nothing, open/close CPP inclusion guards for FILE.
+m4_define([b4_cpp_guard_open],
+[m4_ifval(m4_quote($1),
+[#ifndef b4_cpp_guard([$1])
+# define b4_cpp_guard([$1])])])
 
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 51 Franklin Street, Fifth Floor,
-   Boston, MA 02110-1301, USA.  */
+m4_define([b4_cpp_guard_close],
+[m4_ifval(m4_quote($1),
+[#endif b4_comment([!b4_cpp_guard([$1])])])])
 
-/* As a special exception, you may create a larger work that contains
-   part or all of the Bison parser skeleton and distribute that work
-   under terms of your choice, so long as that work isn't itself a
-   parser generator using the skeleton or a modified version thereof
-   as a parser skeleton.  Alternatively, if you modify or redistribute
-   the parser skeleton itself, you may (at your option) remove this
-   special exception, which will cause the skeleton and the resulting
-   Bison output files to be licensed under the GNU General Public
-   License without this special exception.
 
-   This special exception was added by the Free Software Foundation in
-   version 2.2 of Bison.  */])
+## ---------------- ##
+## Identification.  ##
+## ---------------- ##
 
+# b4_comment(TEXT)
+# ----------------
+m4_define([b4_comment], [/* m4_bpatsubst([$1], [
+], [
+   ])  */])
 
 # 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.
 m4_define([b4_identification],
-[/* Identify Bison output.  */
-[#]define YYBISON 1
+[[/* Identify Bison output.  */
+#define YYBISON 1
 
 /* Bison version.  */
-[#]define YYBISON_VERSION "b4_version"
+#define YYBISON_VERSION "]b4_version["
 
 /* Skeleton name.  */
-[#]define YYSKELETON_NAME b4_skeleton
+#define YYSKELETON_NAME ]b4_skeleton[]m4_ifdef([b4_pure_flag], [[
 
 /* Pure parsers.  */
-[#]define YYPURE b4_pure_flag
+#define YYPURE ]b4_pure_flag])[]m4_ifdef([b4_push_flag], [[
 
-/* Using locations.  */
-[#]define YYLSP_NEEDED b4_locations_flag
-])
+/* Push parsers.  */
+#define YYPUSH ]b4_push_flag])[]m4_ifdef([b4_pull_flag], [[
 
+/* Pull parsers.  */
+#define YYPULL ]b4_pull_flag])[
+]])
 
 
 ## ---------------- ##
 ## Default values.  ##
 ## ---------------- ##
 
-m4_define_default([b4_epilogue], [])
+# 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)])
 
-# If the %union is not named, its name is YYSTYPE.
-m4_define_default([b4_union_name], [YYSTYPE])
 
-# The initial column and line.
-m4_define_default([b4_location_initial_column], [1])
-m4_define_default([b4_location_initial_line],   [1])
+# 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.
+m4_define_default([b4_union_name], [b4_api_PREFIX[]STYPE])
 
 
 ## ------------------------ ##
 ## Pure/impure interfaces.  ##
 ## ------------------------ ##
 
-
 # b4_user_args
 # ------------
 m4_define([b4_user_args],
@@ -111,9 +120,8 @@ m4_define([b4_user_args],
 # --------------
 # If defined, b4_parse_param arrives double quoted, but below we prefer
 # it to be single quoted.
-m4_define_default([b4_parse_param])
 m4_define([b4_parse_param],
-b4_parse_param))
+b4_parse_param)
 
 
 # b4_parse_param_for(DECL, FORMAL, BODY)
@@ -122,7 +130,7 @@ b4_parse_param))
 # the formal name to FORMAL, and evaluating the BODY.
 m4_define([b4_parse_param_for],
 [m4_foreach([$1_$2], m4_defn([b4_parse_param]),
-[m4_pushdef([$1], m4_fst($1_$2))dnl
+[m4_pushdef([$1], m4_unquote(m4_car($1_$2)))dnl
 m4_pushdef([$2], m4_shift($1_$2))dnl
 $3[]dnl
 m4_popdef([$2])dnl
@@ -137,18 +145,11 @@ m4_define([b4_parse_param_use],
 ])dnl
 ])
 
+
 ## ------------ ##
 ## Data Types.  ##
 ## ------------ ##
 
-
-# b4_ints_in(INT1, INT2, LOW, HIGH)
-# ---------------------------------
-# Return 1 iff both INT1 and INT2 are in [LOW, HIGH], 0 otherwise.
-m4_define([b4_ints_in],
-[m4_eval([$3 <= $1 && $1 <= $4 && $3 <= $2 && $2 <= $4])])
-
-
 # b4_int_type(MIN, MAX)
 # ---------------------
 # Return the smallest int type able to handle numbers ranging from
@@ -173,47 +174,43 @@ m4_define([b4_int_type_for],
 [b4_int_type($1_min, $1_max)])
 
 
-## ------------------ ##
-## Decoding options.  ##
-## ------------------ ##
+# 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)))])])
 
-# b4_flag_if(FLAG, IF-TRUE, IF-FALSE)
-# -----------------------------------
-# Run IF-TRUE if b4_FLAG_flag is 1, IF-FALSE if FLAG is 0, otherwise fail.
-m4_define([b4_flag_if],
-[m4_case(b4_$1_flag,
-         [0], [$3],
-	 [1], [$2],
-	 [m4_fatal([invalid $1 value: ]$1)])])
 
+## ---------##
+## Values.  ##
+## ---------##
 
-# b4_define_flag_if(FLAG)
-# -----------------------
-# Define "b4_FLAG_if(IF-TRUE, IF-FALSE)" that depends on the
-# value of the Boolean FLAG.
-m4_define([b4_define_flag_if],
-[_b4_define_flag_if($[1], $[2], [$1])])
-
-# _b4_define_flag_if($1, $2, FLAG)
-# --------------------------------
-# This macro works around the impossibility to define macros
-# inside macros, because issuing `[$1]' is not possible in M4 :(.
-# This sucks hard, GNU M4 should really provide M5 like $$1.
-m4_define([_b4_define_flag_if],
-[m4_if([$1$2], $[1]$[2], [],
-       [m4_fatal([$0: Invalid arguments: $@])])dnl
-m4_define([b4_$3_if],
-          [b4_flag_if([$3], [$1], [$2])])])
-
-
-# b4_FLAG_if(IF-TRUE, IF-FALSE)
-# -----------------------------
-# Expand IF-TRUE, if FLAG is true, IF-FALSE otherwise.
-b4_define_flag_if([defines])        # Whether headers are requested.
-b4_define_flag_if([error_verbose])  # Whether error are verbose.
-b4_define_flag_if([locations])      # Whether locations are tracked.
-b4_define_flag_if([pure])           # Whether the interface is pure.
-b4_define_flag_if([yacc])           # Whether POSIX Yacc is emulated.
+
+# 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])
 
 
 
@@ -233,7 +230,7 @@ m4_define([b4_token_define],
 # -------------------------------------------------------
 # Output the definition of the tokens (if there are) as #defines.
 m4_define([b4_token_defines],
-[m4_if([$@], [[]], [],
+[m4_if([$#$1], [1], [],
 [/* Tokens.  */
 m4_map([b4_token_define], [$@])])
 ])
@@ -250,19 +247,19 @@ m4_define([b4_token_enum],
 # -----------------------------------------------------
 # Output the definition of the tokens (if there are) as enums.
 m4_define([b4_token_enums],
-[m4_if([$@], [[]], [],
-[/* Tokens.  */
-#ifndef YYTOKENTYPE
-# define YYTOKENTYPE
+[m4_if([$#$1], [1], [],
+[[/* Tokens.  */
+#ifndef ]b4_api_PREFIX[TOKENTYPE
+# define ]b4_api_PREFIX[TOKENTYPE
    /* Put the tokens into the symbol table, so that GDB and other debuggers
       know about them.  */
-   enum yytokentype {
-m4_map_sep([     b4_token_enum], [,
+   enum ]b4_api_prefix[tokentype {
+]m4_map_sep([     b4_token_enum], [,
 ],
-	   [$@])
+	   [$@])[
    };
 #endif
-])])
+]])])
 
 
 # b4_token_enums_defines(LIST-OF-PAIRS-TOKEN-NAME-TOKEN-NUMBER)
@@ -302,8 +299,8 @@ m4_define([b4_c_function_def],
 b4_c_ansi_function_def($@)
 #else
 $2
-$1 (b4_c_knr_formal_names(m4_shiftn(2, $@)))
-b4_c_knr_formal_decls(m4_shiftn(2, $@))
+$1 (b4_c_knr_formal_names(m4_shift2($@)))
+b4_c_knr_formal_decls(m4_shift2($@))
 #endif[]dnl
 ])
 
@@ -313,7 +310,7 @@ b4_c_knr_formal_decls(m4_shiftn(2, $@))
 # Declare the function NAME in ANSI.
 m4_define([b4_c_ansi_function_def],
 [$2
-$1 (b4_c_ansi_formals(m4_shiftn(2, $@)))[]dnl
+$1 (b4_c_ansi_formals(m4_shift2($@)))[]dnl
 ])
 
 
@@ -321,9 +318,8 @@ $1 (b4_c_ansi_formals(m4_shiftn(2, $@)))[]dnl
 # --------------------------------------
 # Output the arguments ANSI-C definition.
 m4_define([b4_c_ansi_formals],
-[m4_case([$@],
-	 [],   [void],
-	 [[]], [void],
+[m4_if([$#], [0], [void],
+       [$#$1], [1], [void],
 	       [m4_map_sep([b4_c_ansi_formal], [, ], [$@])])])
 
 m4_define([b4_c_ansi_formal],
@@ -375,7 +371,7 @@ $2 $1 ();
 # ----------------------------------------------------------------
 # Declare the function NAME.
 m4_define([b4_c_ansi_function_decl],
-[$2 $1 (b4_c_ansi_formals(m4_shiftn(2, $@)));[]dnl
+[$2 $1 (b4_c_ansi_formals(m4_shift2($@)));[]dnl
 ])
 
 
@@ -390,7 +386,7 @@ m4_define([b4_c_ansi_function_decl],
 # -----------------------------------------------------------
 # Call the function NAME with arguments NAME1, NAME2 etc.
 m4_define([b4_c_function_call],
-[$1 (b4_c_args(m4_shiftn(2, $@)))[]dnl
+[$1 (b4_c_args(m4_shift2($@)))[]dnl
 ])
 
 
@@ -408,71 +404,38 @@ m4_define([b4_c_arg],
 ## Synclines.  ##
 ## ----------- ##
 
-# b4_basename(NAME)
-# -----------------
-# Similar to POSIX basename; the differences don't matter here.
-# Beware that NAME is not evaluated.
-m4_define([b4_basename],
-[m4_bpatsubst([$1], [^.*/\([^/]+\)/*$], [\1])])
-
-
-# b4_syncline(LINE, FILE)
-# -----------------------
-m4_define([b4_syncline],
-[b4_flag_if([synclines],
-[/* Line __line__ of b4_basename(m4_quote(__file__)).  */
-[#]line $1 $2])])
-
-
-# b4_user_code(USER-CODE)
+# b4_sync_start(LINE, FILE)
 # -----------------------
-# Emit code from the user, ending it with synclines.
-m4_define([b4_user_code],
-[$1
-b4_syncline([@oline@], [@ofile@])])
-
-
-# b4_define_user_code(MACRO)
-# --------------------------
-# From b4_MACRO, build b4_user_MACRO that includes the synclines.
-m4_define([b4_define_user_code],
-[m4_define([b4_user_$1],
-[b4_user_code([b4_$1])])])
-
-
-# b4_user_actions
-# b4_user_initial_action
-# b4_user_post_prologue
-# b4_user_start_header
-# b4_user_stype
-# ----------------------
-# Macros that issue user code, ending with synclines.
-b4_define_user_code([actions])
-b4_define_user_code([initial_action])
-b4_define_user_code([post_prologue])
-b4_define_user_code([start_header])
-b4_define_user_code([stype])
+m4_define([b4_sync_start], [[#]line $1 $2])
 
 
 ## -------------- ##
 ## User actions.  ##
 ## -------------- ##
 
+# b4_case(LABEL, STATEMENTS)
+# --------------------------
+m4_define([b4_case],
+[  case $1:
+$2
+    break;])
+
 # b4_symbol_actions(FILENAME, LINENO,
 #                   SYMBOL-TAG, SYMBOL-NUM,
 #                   SYMBOL-ACTION, SYMBOL-TYPENAME)
 # -------------------------------------------------
+# Issue the code for a symbol action (e.g., %printer).
+#
+# Define b4_dollar_dollar([TYPE-NAME]), and b4_at_dollar, which are
+# invoked where $<TYPE-NAME>$ and @$ were specified by the user.
 m4_define([b4_symbol_actions],
-[m4_pushdef([b4_dollar_dollar],
-   [m4_ifval([$6], [(yyvaluep->$6)], [(*yyvaluep)])])dnl
-m4_pushdef([b4_at_dollar], [(*yylocationp)])dnl
+[b4_dollar_pushdef([(*yyvaluep)], [$6], [(*yylocationp)])dnl
       case $4: /* $3 */
 b4_syncline([$2], [$1])
 	$5;
 b4_syncline([@oline@], [@ofile@])
 	break;
-m4_popdef([b4_at_dollar])dnl
-m4_popdef([b4_dollar_dollar])dnl
+b4_dollar_popdef[]dnl
 ])
 
 
@@ -534,6 +497,8 @@ m4_define_default([b4_yy_symbol_print_generate],
 b4_locations_if([, [[YYLTYPE const * const yylocationp], [yylocationp]]])[]dnl
 m4_ifset([b4_parse_param], [, b4_parse_param]))[
 {
+  FILE *yyo = yyoutput;
+  YYUSE (yyo);
   if (!yyvaluep)
     return;
 ]b4_locations_if([  YYUSE (yylocationp);
@@ -579,3 +544,145 @@ b4_locations_if([, yylocationp])[]b4_user_args[);
   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 ]b4_api_PREFIX[STYPE /* obsolescent; will be withdrawn */
+# 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 ]b4_api_PREFIX[LTYPE /* obsolescent; will be withdrawn */
+# 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_debug_flag[
+#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_debug_flag[
+# endif /* ! defined YYDEBUG */
+#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
+]])
+
+# b4_yy_location_print_define
+# ---------------------------
+# Define YY_LOCATION_PRINT.
+m4_define([b4_yy_location_print_define],
+[b4_locations_if([[
+/* YY_LOCATION_PRINT -- Print the location on the stream.
+   This macro was not mandated originally: define only if we know
+   we won't break user code: when these are the locations we know.  */
+
+#ifndef YY_LOCATION_PRINT
+# if defined ]b4_api_PREFIX[LTYPE_IS_TRIVIAL && ]b4_api_PREFIX[LTYPE_IS_TRIVIAL
+#  define YY_LOCATION_PRINT(File, Loc)                                   \
+  do {                                                                   \
+    fprintf (File, "%d.%d", (Loc).first_line, (Loc).first_column);       \
+    if ((Loc).first_line < (Loc).last_line)                              \
+      fprintf (File, "-%d.%d", (Loc).last_line,  (Loc).last_column - 1); \
+    else if ((Loc).first_column < (Loc).last_column - 1)                 \
+      fprintf (File, "-%d", (Loc).last_column - 1);                      \
+  } while (0)
+# else
+#  define YY_LOCATION_PRINT(File, Loc) ((void) 0)
+# endif
+#endif]],
+[[/* This macro is provided for backward compatibility. */
+#ifndef YY_LOCATION_PRINT
+# define YY_LOCATION_PRINT(File, Loc) ((void) 0)
+#endif]])
+])
+
+# b4_yyloc_default
+# ----------------
+# Expand to a possible default value for yylloc.
+m4_define([b4_yyloc_default],
+[[
+# if defined ]b4_api_PREFIX[LTYPE_IS_TRIVIAL && ]b4_api_PREFIX[LTYPE_IS_TRIVIAL
+  = { ]m4_join([, ],
+               m4_defn([b4_location_initial_line]),
+               m4_defn([b4_location_initial_column]),
+               m4_defn([b4_location_initial_line]),
+               m4_defn([b4_location_initial_column]))[ }
+# endif
+]])