X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/136a0f766b38072ec6ac6c386b230e04d4146151..5aaad6c43154f3e69c4e49616d29b1f95b012881:/data/bison.m4
diff --git a/data/bison.m4 b/data/bison.m4
index 87d113b6..37bc012f 100644
--- a/data/bison.m4
+++ b/data/bison.m4
@@ -1,41 +1,43 @@
-m4_divert(-1) -*- Autoconf -*-
+ -*- Autoconf -*-
# Language-independent 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 .
## ---------------- ##
## Identification. ##
## ---------------- ##
-# b4_copyright(TITLE, YEARS)
-# --------------------------
+# b4_copyright(TITLE, [YEARS])
+# ----------------------------
+# If YEARS are not defined, use b4_copyright_years.
m4_define([b4_copyright],
[b4_comment([A Bison parser, made by GNU Bison b4_version.])
b4_comment([$1
-m4_text_wrap([Copyright (C) $2 Free Software Foundation, Inc.], [ ])
+]m4_dquote(m4_text_wrap([Copyright (C)
+]m4_ifval([$2], [[$2]], [m4_defn([b4_copyright_years])])[
+Free Software Foundation, Inc.]))[
-This program is free software; you can redistribute it and/or modify
+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.
+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
@@ -43,9 +45,7 @@ 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 .])
b4_comment([As a special exception, you may create a larger work that contains
part or all of the Bison parser skeleton and distribute that work
@@ -61,11 +61,138 @@ This special exception was added by the Free Software Foundation in
version 2.2 of Bison.])])
+## ---------------- ##
+## Error handling. ##
+## ---------------- ##
+
+# The following error handling macros print error directives that should not
+# become arguments of other macro invocations since they would likely then be
+# mangled. Thus, they print to stdout directly.
+
+# b4_cat(TEXT)
+# ------------
+# Write TEXT to stdout. Precede the final newline with an @ so that it's
+# escaped. For example:
+#
+# b4_cat([[@complain(invalid input@)]])
+m4_define([b4_cat],
+[m4_syscmd([cat <<'_m4eof'
+]m4_bpatsubst(m4_dquote($1), [_m4eof], [_m4@`eof])[@
+_m4eof
+])dnl
+m4_if(m4_sysval, [0], [], [m4_fatal([$0: cannot write to stdout])])])
+
+# b4_error(KIND, FORMAT, [ARG1], [ARG2], ...)
+# -------------------------------------------
+# Write @KIND(FORMAT@,ARG1@,ARG2@,...@) to stdout.
+#
+# For example:
+#
+# b4_error([[warn]], [[invalid value for '%s': %s]], [[foo]], [[3]])
+m4_define([b4_error],
+[b4_cat([[@]$1[(]$2[]]dnl
+[m4_if([$#], [2], [],
+ [m4_foreach([b4_arg],
+ m4_dquote(m4_shift(m4_shift($@))),
+ [[@,]b4_arg])])[@)]])])
+
+# b4_error_at(KIND, START, END, FORMAT, [ARG1], [ARG2], ...)
+# ----------------------------------------------------------
+# Write @KIND_at(START@,END@,FORMAT@,ARG1@,ARG2@,...@) to stdout.
+#
+# For example:
+#
+# b4_error_at([[complain]], [[input.y:2.3]], [[input.y:5.4]],
+# [[invalid %s]], [[foo]])
+m4_define([b4_error_at],
+[b4_cat([[@]$1[_at(]$2[@,]$3[@,]$4[]]dnl
+[m4_if([$#], [4], [],
+ [m4_foreach([b4_arg],
+ m4_dquote(m4_shift(m4_shift(m4_shift(m4_shift($@))))),
+ [[@,]b4_arg])])[@)]])])
+
+# b4_warn(FORMAT, [ARG1], [ARG2], ...)
+# ------------------------------------
+# Write @warn(FORMAT@,ARG1@,ARG2@,...@) to stdout.
+#
+# For example:
+#
+# b4_warn([[invalid value for '%s': %s]], [[foo]], [[3]])
+#
+# As a simple test suite, this:
+#
+# m4_divert(-1)
+# m4_define([asdf], [ASDF])
+# m4_define([fsa], [FSA])
+# m4_define([fdsa], [FDSA])
+# b4_warn([[[asdf), asdf]]], [[[fsa), fsa]]], [[[fdsa), fdsa]]])
+# b4_warn([[asdf), asdf]], [[fsa), fsa]], [[fdsa), fdsa]])
+# b4_warn()
+# b4_warn(1)
+# b4_warn(1, 2)
+#
+# Should produce this without newlines:
+#
+# @warn([asdf), asdf]@,[fsa), fsa]@,[fdsa), fdsa]@)
+# @warn(asdf), asdf@,fsa), fsa@,fdsa), fdsa@)
+# @warn(@)
+# @warn(1@)
+# @warn(1@,2@)
+m4_define([b4_warn],
+[b4_error([[warn]], $@)])
+
+# b4_warn_at(START, END, FORMAT, [ARG1], [ARG2], ...)
+# ---------------------------------------------------
+# Write @warn(START@,END@,FORMAT@,ARG1@,ARG2@,...@) to stdout.
+#
+# For example:
+#
+# b4_warn_at([[input.y:2.3]], [[input.y:5.4]], [[invalid %s]], [[foo]])
+m4_define([b4_warn_at],
+[b4_error_at([[warn]], $@)])
+
+# b4_complain(FORMAT, [ARG1], [ARG2], ...)
+# ----------------------------------------
+# Write @complain(FORMAT@,ARG1@,ARG2@,...@) to stdout.
+#
+# See b4_warn example.
+m4_define([b4_complain],
+[b4_error([[complain]], $@)])
+
+# b4_complain_at(START, END, FORMAT, [ARG1], [ARG2], ...)
+# -------------------------------------------------------
+# Write @complain(START@,END@,FORMAT@,ARG1@,ARG2@,...@) to stdout.
+#
+# See b4_warn_at example.
+m4_define([b4_complain_at],
+[b4_error_at([[complain]], $@)])
+
+# b4_fatal(FORMAT, [ARG1], [ARG2], ...)
+# -------------------------------------
+# Write @fatal(FORMAT@,ARG1@,ARG2@,...@) to stdout and exit.
+#
+# See b4_warn example.
+m4_define([b4_fatal],
+[b4_error([[fatal]], $@)dnl
+m4_exit(1)])
+
+# b4_fatal_at(START, END, FORMAT, [ARG1], [ARG2], ...)
+# ----------------------------------------------------
+# Write @fatal(START@,END@,FORMAT@,ARG1@,ARG2@,...@) to stdout and exit.
+#
+# See b4_warn_at example.
+m4_define([b4_fatal_at],
+[b4_error_at([[fatal]], $@)dnl
+m4_exit(1)])
+
+
## ---------------- ##
## Default values. ##
## ---------------- ##
# m4_define_default([b4_lex_param], []) dnl breaks other skeletons
+m4_define_default([b4_pre_prologue], [])
+m4_define_default([b4_post_prologue], [])
m4_define_default([b4_epilogue], [])
m4_define_default([b4_parse_param], [])
@@ -85,6 +212,87 @@ m4_define([b4_ints_in],
[m4_eval([$3 <= $1 && $1 <= $4 && $3 <= $2 && $2 <= $4])])
+# b4_subtract(LHS, RHS)
+# ---------------------
+# Evaluate LHS - RHS if they are integer literals, otherwise expand
+# to (LHS) - (RHS).
+m4_define([b4_subtract],
+[m4_bmatch([$1$2], [^[0123456789]*$],
+ [m4_eval([$1 - $2])],
+ [($1) - ($2)])])
+
+# b4_args(ARG1, ...)
+# _b4_args(ARG1, ...)
+# -------------------
+# Join with comma, skipping empty arguments.
+# b4_args calls itself recursively until it sees the first non-empty
+# argument, then calls _b4_args which prepends each non-empty argument
+# with a comma.
+m4_define([b4_args],
+[m4_if([$#$1],
+ [1], [],
+ [m4_ifval([$1],
+ [$1[]_$0(m4_shift($@))],
+ [$0(m4_shift($@))])])])
+
+# _b4_args(ARGS1, ...)
+# --------------------
+m4_define([_b4_args],
+[m4_if([$#$1],
+ [1], [],
+ [m4_ifval([$1], [, $1])[]$0(m4_shift($@))])])
+
+
+
+
+# b4_integral_parser_tables_map(MACRO)
+# -------------------------------------
+# Map MACRO on all the integral tables. MACRO is expected to have
+# the signature MACRO(TABLE-NAME, CONTENT, COMMENT).
+m4_define([b4_integral_parser_tables_map],
+[$1([pact], [b4_pact],
+ [[YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
+STATE-NUM.]])
+
+$1([defact], [b4_defact],
+ [[YYDEFACT[S] -- default reduction number in state S. Performed when
+YYTABLE does not specify something else to do. Zero means the default
+is an error.]])
+
+$1([pgoto], [b4_pgoto], [[YYPGOTO[NTERM-NUM].]])
+
+$1([defgoto], [b4_defgoto], [[YYDEFGOTO[NTERM-NUM].]])
+
+$1([table], [b4_table],
+ [[YYTABLE[YYPACT[STATE-NUM]]. What to do in state STATE-NUM. If
+positive, shift that token. If negative, reduce the rule which
+number is the opposite. If YYTABLE_NINF, syntax error.]])
+
+$1([check], [b4_check])
+
+$1([stos], [b4_stos],
+ [[STOS_[STATE-NUM] -- The (internal number of the) accessing
+symbol of state STATE-NUM.]])
+
+$1([r1], [b4_r1],
+ [[YYR1[YYN] -- Symbol number of symbol that rule YYN derives.]])
+
+$1([r2], [b4_r2],
+ [[YYR2[YYN] -- Number of symbols composing right hand side of rule YYN.]])
+])
+
+
+# b4_parser_tables_declare
+# b4_parser_tables_define
+# ------------------------
+# Define/declare the (deterministic) parser tables.
+m4_define([b4_parser_tables_declare],
+[b4_integral_parser_tables_map([b4_integral_parser_table_declare])])
+
+m4_define([b4_parser_tables_define],
+[b4_integral_parser_tables_map([b4_integral_parser_table_define])])
+
+
## ------------------ ##
## Decoding options. ##
@@ -96,8 +304,8 @@ m4_define([b4_ints_in],
m4_define([b4_flag_if],
[m4_case(b4_$1_flag,
[0], [$3],
- [1], [$2],
- [m4_fatal([invalid $1 value: ]$1)])])
+ [1], [$2],
+ [m4_fatal([invalid $1 value: ]$1)])])
# b4_define_flag_if(FLAG)
@@ -122,19 +330,121 @@ m4_define([b4_$3_if],
# 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([glr]) # Whether a GLR parser is requested.
-b4_define_flag_if([locations]) # Whether locations are tracked.
-b4_define_flag_if([nondeterministic]) # Whether conflicts should be handled.
-b4_define_flag_if([pure]) # Whether the interface is pure.
-b4_define_flag_if([push]) # Whether push parsing is supported.
-b4_define_flag_if([yacc]) # Whether POSIX Yacc is emulated.
+b4_define_flag_if([defines]) # Whether headers are requested.
+b4_define_flag_if([glr]) # Whether a GLR parser is requested.
+b4_define_flag_if([nondeterministic]) # Whether conflicts should be handled.
+b4_define_flag_if([yacc]) # Whether POSIX Yacc is emulated.
+
+
+## --------- ##
+## Symbols. ##
+## --------- ##
+
+# b4_symbol_(NUM, FIELD)
+# ----------------------
+# Recover a FIELD about symbol #NUM. Thanks to m4_indir, fails if
+# undefined.
+m4_define([b4_symbol_],
+[m4_indir([b4_symbol($1, $2)])])
+
+
+# b4_symbol(NUM, FIELD)
+# ---------------------
+# Recover a FIELD about symbol #NUM. Thanks to m4_indir, fails if
+# undefined. If FIELD = id, prepend the prefix.
+m4_define([b4_symbol],
+[m4_case([$2],
+ [id], [m4_do([b4_percent_define_get([api.tokens.prefix])],
+ [b4_symbol_([$1], [id])])],
+ [b4_symbol_($@)])])
+
+
+# b4_symbol_if(NUM, FIELD, IF-TRUE, IF-FALSE)
+# -------------------------------------------
+# If FIELD about symbol #NUM is 1 expand IF-TRUE, if is 0, expand IF-FALSE.
+# Otherwise an error.
+m4_define([b4_symbol_if],
+[m4_case(b4_symbol([$1], [$2]),
+ [1], [$3],
+ [0], [$4],
+ [m4_fatal([$0: field $2 of $1 is not a Boolean:] b4_symbol([$1], [$2]))])])
+
+
+# b4_symbol_action_location(SYMBOL-NUM, KIND)
+# -------------------------------------------
+# Report the location of the KIND action as FILE:LINE.
+m4_define([b4_symbol_action_location],
+[b4_symbol([$1], [$2_file]):b4_syncline([b4_symbol([$1], [$2_line])])])
+
+
+# b4_symbol_action(SYMBOL-NUM, KIND)
+# ----------------------------------
+# Run the action KIND (destructor or printer) for SYMBOL-NUM.
+# Same as in C, but using references instead of pointers.
+m4_define([b4_symbol_action],
+[b4_symbol_if([$1], [has_$2],
+[m4_pushdef([b4_dollar_dollar],
+ [b4_symbol_value([(*yyvaluep)],
+ b4_symbol_if([$1], [has_type],
+ [b4_symbol([$1], [type])]))])dnl
+m4_pushdef([b4_at_dollar], [(*yylocationp)])dnl
+ b4_symbol_case_([$1])
+b4_syncline([b4_symbol([$1], [$2_line])], ["b4_symbol([$1], [$2_file])"])
+ b4_symbol([$1], [$2])
+b4_syncline([@oline@], [@ofile@])
+ break;
+
+m4_popdef([b4_at_dollar])dnl
+m4_popdef([b4_dollar_dollar])dnl
+])])
+
+
+# b4_symbol_destructor(SYMBOL-NUM)
+# b4_symbol_printer(SYMBOL-NUM)
+# --------------------------------
+m4_define([b4_symbol_destructor], [b4_symbol_action([$1], [destructor])])
+m4_define([b4_symbol_printer], [b4_symbol_action([$1], [printer])])
+
+
+# b4_symbol_case_(SYMBOL-NUM)
+# ---------------------------
+# Issue a "case NUM" for SYMBOL-NUM.
+m4_define([b4_symbol_case_],
+[ case b4_symbol([$1], [number]): // b4_symbol([$1], [tag])
+])
+
+
+# b4_symbol_foreach(MACRO)
+# ------------------------
+# Invoke MACRO(SYMBOL-NUM) for each SYMBOL-NUM.
+m4_define([b4_symbol_foreach],
+ [m4_map([$1], m4_defn([b4_symbol_numbers]))])
-## ------------------------- ##
-## Assigning token numbers. ##
-## ------------------------- ##
+## ------- ##
+## Types. ##
+## ------- ##
+
+# b4_type_action_(NUMS)
+# ---------------------
+# Run actions for the symbol NUMS that all have the same type-name.
+# Skip NUMS that have no type-name.
+m4_define([b4_type_action_],
+[b4_symbol_if([$1], [has_type],
+[m4_map([b4_symbol_case_], [$@])[]dnl
+ b4_dollar_dollar([b4_symbol([$1], [number])],
+ [b4_symbol([$1], [tag])],
+ [b4_symbol([$1], [type])]);
+ break;
+
+])])
+
+# b4_type_foreach(MACRO)
+# ----------------------
+# Invoke MACRO(SYMBOL-NUMS) for each set of SYMBOL-NUMS for each type set.
+m4_define([b4_type_foreach],
+ [m4_map([$1], m4_defn([b4_type_names]))])
+
## ----------- ##
@@ -152,8 +462,8 @@ m4_define([b4_basename],
# b4_syncline(LINE, FILE)
# -----------------------
m4_define([b4_syncline],
-[b4_flag_if([synclines], [
-b4_sync_end([__line__], [b4_basename(m4_quote(__file__))])
+[b4_flag_if([synclines],
+[b4_sync_end([__line__], [b4_basename(m4_quote(__file__))])
b4_sync_start([$1], [$2])])])
m4_define([b4_sync_end], [b4_comment([Line $1 of $2])])
@@ -179,8 +489,6 @@ m4_define([b4_define_user_code],
# b4_user_initial_action
# b4_user_post_prologue
# b4_user_pre_prologue
-# b4_user_provides
-# b4_user_requires
# b4_user_stype
# ----------------------
# Macros that issue user code, ending with synclines.
@@ -188,8 +496,325 @@ b4_define_user_code([actions])
b4_define_user_code([initial_action])
b4_define_user_code([post_prologue])
b4_define_user_code([pre_prologue])
-b4_define_user_code([provides])
-b4_define_user_code([requires])
b4_define_user_code([stype])
+# b4_check_user_names(WHAT, USER-LIST, BISON-NAMESPACE)
+# -----------------------------------------------------
+# Complain if any name of type WHAT is used by the user (as recorded in
+# USER-LIST) but is not used by Bison (as recorded by macros in the
+# namespace BISON-NAMESPACE).
+#
+# USER-LIST must expand to a list specifying all user occurrences of all names
+# of type WHAT. Each item in the list must be a triplet specifying one
+# occurrence: name, start boundary, and end boundary. Empty string names are
+# fine. An empty list is fine.
+#
+# For example, to define b4_foo_user_names to be used for USER-LIST with three
+# name occurrences and with correct quoting:
+#
+# m4_define([b4_foo_user_names],
+# [[[[[[bar]], [[parser.y:1.7]], [[parser.y:1.16]]]],
+# [[[[bar]], [[parser.y:5.7]], [[parser.y:5.16]]]],
+# [[[[baz]], [[parser.y:8.7]], [[parser.y:8.16]]]]]])
+#
+# The macro BISON-NAMESPACE(bar) must be defined iff the name bar of type WHAT
+# is used by Bison (in the front-end or in the skeleton). Empty string names
+# are fine, but it would be ugly for Bison to actually use one.
+#
+# For example, to use b4_foo_bison_names for BISON-NAMESPACE and define that
+# the names bar and baz are used by Bison:
+#
+# m4_define([b4_foo_bison_names(bar)])
+# m4_define([b4_foo_bison_names(baz)])
+#
+# To invoke b4_check_user_names with TYPE foo, with USER-LIST
+# b4_foo_user_names, with BISON-NAMESPACE b4_foo_bison_names, and with correct
+# quoting:
+#
+# b4_check_user_names([[foo]], [b4_foo_user_names],
+# [[b4_foo_bison_names]])
+m4_define([b4_check_user_names],
+[m4_foreach([b4_occurrence], $2,
+[m4_pushdef([b4_occurrence], b4_occurrence)dnl
+m4_pushdef([b4_user_name], m4_car(b4_occurrence))dnl
+m4_pushdef([b4_start], m4_car(m4_shift(b4_occurrence)))dnl
+m4_pushdef([b4_end], m4_shift(m4_shift(b4_occurrence)))dnl
+m4_ifndef($3[(]m4_quote(b4_user_name)[)],
+ [b4_complain_at([b4_start], [b4_end],
+ [[%s '%s' is not used]],
+ [$1], [b4_user_name])])[]dnl
+m4_popdef([b4_occurrence])dnl
+m4_popdef([b4_user_name])dnl
+m4_popdef([b4_start])dnl
+m4_popdef([b4_end])dnl
+])])
+
+
+
+## --------------------- ##
+## b4_percent_define_*. ##
+## --------------------- ##
+
+
+# b4_percent_define_use(VARIABLE)
+# -------------------------------
+# Declare that VARIABLE was used.
+m4_define([b4_percent_define_use],
+[m4_define([b4_percent_define_bison_variables(]$1[)])dnl
+])
+
+# b4_percent_define_get(VARIABLE, [DEFAULT])
+# ------------------------------------------
+# Mimic muscle_percent_define_get in ../src/muscle-tab.h. That is, if
+# the %define variable VARIABLE is defined, emit its value. Contrary
+# to its C counterpart, return DEFAULT otherwise. Also, record
+# Bison's usage of VARIABLE by defining
+# b4_percent_define_bison_variables(VARIABLE).
+#
+# For example:
+#
+# b4_percent_define_get([[foo]])
+m4_define([b4_percent_define_get],
+[b4_percent_define_use([$1])dnl
+m4_ifdef([b4_percent_define(]$1[)],
+ [m4_indir([b4_percent_define(]$1[)])],
+ [$2])])
+
+# b4_percent_define_get_loc(VARIABLE)
+# -----------------------------------
+# Mimic muscle_percent_define_get_loc in ../src/muscle-tab.h exactly. That is,
+# if the %define variable VARIABLE is undefined, complain fatally since that's
+# a Bison or skeleton error. Otherwise, return its definition location in a
+# form approriate for the first two arguments of b4_warn_at, b4_complain_at, or
+# b4_fatal_at. Don't record this as a Bison usage of VARIABLE as there's no
+# reason to suspect that the user-supplied value has yet influenced the output.
+#
+# For example:
+#
+# b4_complain_at(b4_percent_define_get_loc([[foo]]), [[invalid foo]])
+m4_define([b4_percent_define_get_loc],
+[m4_ifdef([b4_percent_define_loc(]$1[)],
+ [m4_pushdef([b4_loc], m4_indir([b4_percent_define_loc(]$1[)]))dnl
+b4_loc[]dnl
+m4_popdef([b4_loc])],
+ [b4_fatal([[b4_percent_define_get_loc: undefined %%define variable '%s']], [$1])])])
+
+# b4_percent_define_get_syncline(VARIABLE)
+# ----------------------------------------
+# Mimic muscle_percent_define_get_syncline in ../src/muscle-tab.h exactly.
+# That is, if the %define variable VARIABLE is undefined, complain fatally
+# since that's a Bison or skeleton error. Otherwise, return its definition
+# location as a b4_syncline invocation. Don't record this as a Bison usage of
+# VARIABLE as there's no reason to suspect that the user-supplied value has yet
+# influenced the output.
+#
+# For example:
+#
+# b4_percent_define_get_syncline([[foo]])
+m4_define([b4_percent_define_get_syncline],
+[m4_ifdef([b4_percent_define_syncline(]$1[)],
+ [m4_indir([b4_percent_define_syncline(]$1[)])],
+ [b4_fatal([[b4_percent_define_get_syncline: undefined %%define variable '%s']], [$1])])])
+
+# b4_percent_define_ifdef(VARIABLE, IF-TRUE, [IF-FALSE])
+# ------------------------------------------------------
+# Mimic muscle_percent_define_ifdef in ../src/muscle-tab.h exactly. That is,
+# if the %define variable VARIABLE is defined, expand IF-TRUE, else expand
+# IF-FALSE. Also, record Bison's usage of VARIABLE by defining
+# b4_percent_define_bison_variables(VARIABLE).
+#
+# For example:
+#
+# b4_percent_define_ifdef([[foo]], [[it's defined]], [[it's undefined]])
+m4_define([b4_percent_define_ifdef],
+[m4_ifdef([b4_percent_define(]$1[)],
+ [b4_percent_define_use([$1])$2],
+ [$3])])
+
+
+## --------- ##
+## Options. ##
+## --------- ##
+
+
+# b4_percent_define_flag_if(VARIABLE, IF-TRUE, [IF-FALSE])
+# --------------------------------------------------------
+# Mimic muscle_percent_define_flag_if in ../src/muscle-tab.h exactly. That is,
+# if the %define variable VARIABLE is defined to "" or "true", expand IF-TRUE.
+# If it is defined to "false", expand IF-FALSE. Complain if it is undefined
+# (a Bison or skeleton error since the default value should have been set
+# already) or defined to any other value (possibly a user error). Also, record
+# Bison's usage of VARIABLE by defining
+# b4_percent_define_bison_variables(VARIABLE).
+#
+# For example:
+#
+# b4_percent_define_flag_if([[foo]], [[it's true]], [[it's false]])
+m4_define([b4_percent_define_flag_if],
+[b4_percent_define_ifdef([$1],
+ [m4_case(b4_percent_define_get([$1]),
+ [], [$2], [true], [$2], [false], [$3],
+ [m4_expand_once([b4_complain_at(b4_percent_define_get_loc([$1]),
+ [[invalid value for %%define Boolean variable '%s']],
+ [$1])],
+ [[b4_percent_define_flag_if($1)]])])],
+ [b4_fatal([[b4_percent_define_flag_if: undefined %%define variable '%s']], [$1])])])
+
+
+# b4_percent_define_default(VARIABLE, DEFAULT)
+# --------------------------------------------
+# Mimic muscle_percent_define_default in ../src/muscle-tab.h exactly. That is,
+# if the %define variable VARIABLE is undefined, set its value to DEFAULT.
+# Don't record this as a Bison usage of VARIABLE as there's no reason to
+# suspect that the value has yet influenced the output.
+#
+# For example:
+#
+# b4_percent_define_default([[foo]], [[default value]])
+m4_define([b4_percent_define_default],
+[m4_ifndef([b4_percent_define(]$1[)],
+ [m4_define([b4_percent_define(]$1[)], [$2])dnl
+ m4_define([b4_percent_define_loc(]$1[)],
+ [[[[:-1.-1]],
+ [[:-1.-1]]]])dnl
+ m4_define([b4_percent_define_syncline(]$1[)], [[]])])])
+
+
+# b4_percent_define_if_define(VARIABLE)
+# -------------------------------------
+# Define b4_VARIABLE_if that executes its $1 or $2 depending whether
+# VARIABLE was %defined. The characters `.' and `-' in VARIABLE are mapped
+# to `_'.
+m4_define([b4_percent_define_if_define_],
+[m4_define(m4_bpatsubst([b4_$1_if], [[-.]], [_]),
+ [b4_percent_define_flag_if([$1], [$2], [$3])])])
+m4_define([b4_percent_define_if_define],
+[b4_percent_define_default([[$1]], [[false]])
+b4_percent_define_if_define_([$1], $[1], $[2])])
+
+
+# b4_percent_define_check_values(VALUES)
+# --------------------------------------
+# Mimic muscle_percent_define_check_values in ../src/muscle-tab.h exactly
+# except that the VALUES structure is more appropriate for M4. That is, VALUES
+# is a list of sublists of strings. For each sublist, the first string is the
+# name of a %define variable, and all remaining strings in that sublist are the
+# valid values for that variable. Complain if such a variable is undefined (a
+# Bison error since the default value should have been set already) or defined
+# to any other value (possibly a user error). Don't record this as a Bison
+# usage of the variable as there's no reason to suspect that the value has yet
+# influenced the output.
+#
+# For example:
+#
+# b4_percent_define_check_values([[[[foo]], [[foo-value1]], [[foo-value2]]]],
+# [[[[bar]], [[bar-value1]]]])
+m4_define([b4_percent_define_check_values],
+[m4_foreach([b4_sublist], m4_quote($@),
+ [_b4_percent_define_check_values(b4_sublist)])])
+
+m4_define([_b4_percent_define_check_values],
+[m4_ifdef([b4_percent_define(]$1[)],
+ [m4_pushdef([b4_good_value], [0])dnl
+ m4_if($#, 1, [],
+ [m4_foreach([b4_value], m4_dquote(m4_shift($@)),
+ [m4_if(m4_indir([b4_percent_define(]$1[)]), b4_value,
+ [m4_define([b4_good_value], [1])])])])dnl
+ m4_if(b4_good_value, [0],
+ [b4_complain_at(b4_percent_define_get_loc([$1]),
+ [[invalid value for %%define variable '%s': '%s']],
+ [$1],
+ m4_dquote(m4_indir([b4_percent_define(]$1[)])))
+ m4_foreach([b4_value], m4_dquote(m4_shift($@)),
+ [b4_complain_at(b4_percent_define_get_loc([$1]),
+ [[accepted value: '%s']],
+ m4_dquote(b4_value))])])dnl
+ m4_popdef([b4_good_value])],
+ [b4_fatal([[b4_percent_define_check_values: undefined %%define variable '%s']], [$1])])])
+
+# b4_percent_code_get([QUALIFIER])
+# --------------------------------
+# If any %code blocks for QUALIFIER are defined, emit them beginning with a
+# comment and ending with synclines and a newline. If QUALIFIER is not
+# specified or empty, do this for the unqualified %code blocks. Also, record
+# Bison's usage of QUALIFIER (if specified) by defining
+# b4_percent_code_bison_qualifiers(QUALIFIER).
+#
+# For example, to emit any unqualified %code blocks followed by any %code
+# blocks for the qualifier foo:
+#
+# b4_percent_code_get
+# b4_percent_code_get([[foo]])
+m4_define([b4_percent_code_get],
+[m4_pushdef([b4_macro_name], [[b4_percent_code(]$1[)]])dnl
+m4_ifval([$1], [m4_define([b4_percent_code_bison_qualifiers(]$1[)])])dnl
+m4_ifdef(b4_macro_name,
+[b4_comment([m4_if([$#], [0], [[Unqualified %code]],
+ [["%code ]$1["]])[ blocks.]])
+b4_user_code([m4_indir(b4_macro_name)])
+])dnl
+m4_popdef([b4_macro_name])])
+
+# b4_percent_code_ifdef(QUALIFIER, IF-TRUE, [IF-FALSE])
+# -----------------------------------------------------
+# If any %code blocks for QUALIFIER (or unqualified %code blocks if
+# QUALIFIER is empty) are defined, expand IF-TRUE, else expand IF-FALSE.
+# Also, record Bison's usage of QUALIFIER (if specified) by defining
+# b4_percent_code_bison_qualifiers(QUALIFIER).
+m4_define([b4_percent_code_ifdef],
+[m4_ifdef([b4_percent_code(]$1[)],
+ [m4_ifval([$1], [m4_define([b4_percent_code_bison_qualifiers(]$1[)])])$2],
+ [$3])])
+
+
+## ------------------ ##
+## Common variables. ##
+## ------------------ ##
+
+# Default values for %define.
+# ---------------------------
+# If the api.tokens.prefix, it is empty.
+m4_percent_define_default([[api.tokens.prefix]], [[]])
+
+# b4_parse_assert_if([IF-ASSERTIONS-ARE-USED], [IF-NOT])
+# b4_parse_trace_if([IF-DEBUG-TRACES-ARE-ENABLED], [IF-NOT])
+# b4_lex_symbol_if([IF-YYLEX-RETURNS-A-COMPLETE-SYMBOL], [IF-NOT])
+# b4_variant_if([IF-VARIANT-ARE-USED], [IF-NOT])
+# ----------------------------------------------
+b4_percent_define_if_define([lex_symbol])
+b4_percent_define_if_define([locations]) # Whether locations are tracked.
+b4_percent_define_if_define([parse.assert])
+b4_percent_define_if_define([parse.trace])
+b4_percent_define_if_define([variant])
+
+
+# b4_error_verbose_if([IF-ERRORS-ARE-VERBOSE], [IF-NOT])
+# ------------------------------------------------------
+# Map %define parse.error "(simple|verbose)" to b4_error_verbose_if and
+# b4_error_verbose_flag.
+b4_percent_define_default([[parse.error]], [[simple]])
+b4_percent_define_check_values([[[[parse.error]],
+ [[simple]], [[verbose]]]])
+m4_define([b4_error_verbose_flag],
+ [m4_case(b4_percent_define_get([[parse.error]]),
+ [simple], [[0]],
+ [verbose], [[1]])])
+b4_define_flag_if([error_verbose])
+
+
+## ----------------------------------------------------------- ##
+## After processing the skeletons, check that all the user's ##
+## %define variables and %code qualifiers were used by Bison. ##
+## ----------------------------------------------------------- ##
+
+m4_define([b4_check_user_names_wrap],
+[m4_ifdef([b4_percent_]$1[_user_]$2[s],
+ [b4_check_user_names([[%]$1 $2],
+ [b4_percent_]$1[_user_]$2[s],
+ [[b4_percent_]$1[_bison_]$2[s]])])])
+
+m4_wrap_lifo([
+b4_check_user_names_wrap([[define]], [[variable]])
+b4_check_user_names_wrap([[code]], [[qualifier]])
+])