X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/592d0b1eb5a6e8041df3d1461dc9fca60e3e0a54..1c72905811fa75e0715eb5ec1066dfcae520d070:/data/bison.m4

diff --git a/data/bison.m4 b/data/bison.m4
index cc6a2b90..384f875a 100644
--- a/data/bison.m4
+++ b/data/bison.m4
@@ -1,41 +1,43 @@
                                                             -*- Autoconf -*-
 
 # Language-independent M4 Macros for Bison.
-# Copyright (C) 2002, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+# Copyright (C) 2002, 2004, 2005, 2006, 2007, 2008, 2009
+# 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 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/>.
 
 
 ## ---------------- ##
 ## 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 <http://www.gnu.org/licenses/>.])
 
 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
@@ -65,50 +65,76 @@ 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 diversion 0.
+# Write @KIND(FORMAT@,ARG1@,ARG2@,...@) to stdout.
+#
+# For example:
+#
+#   b4_error([[warn]], [[invalid value for `%s': %s]], [[foo]], [[3]])
 m4_define([b4_error],
-[m4_divert_push(0)[@]$1[(]$2[]m4_if([$#], [2], [],
-[m4_foreach([b4_arg],
-            m4_dquote(m4_shift(m4_shift($@))),
-            [[@,]b4_arg])])[@)]m4_divert_pop(0)])
+[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(START@,END@,FORMAT@,ARG1@,ARG2@,...@) to diversion 0.
+# 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],
-[m4_divert_push(0)[@]$1[_at(]$2[@,]$3[@,]$4[]m4_if([$#], [4], [],
-[m4_foreach([b4_arg],
-            m4_dquote(m4_shift(m4_shift(m4_shift(m4_shift($@))))),
-            [[@,]b4_arg])])[@)]m4_divert_pop(0)])
+[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 diversion 0.
+# 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]]])
-#   m4_divert(0)
 #   b4_warn([[asdf), asdf]], [[fsa), fsa]], [[fdsa), fdsa]])
-#   m4_divert(0)
-#   b4_warn([asdf), asdf], [fsa), fsa], [fdsa), fdsa])
-#   m4_divert(0)
 #   b4_warn()
-#   m4_divert(0)
 #   b4_warn(1)
-#   m4_divert(0)
 #   b4_warn(1, 2)
 #
-# Should produce this:
+# Should produce this without newlines:
 #
 #   @warn([asdf), asdf]@,[fsa), fsa]@,[fdsa), fdsa]@)
 #   @warn(asdf), asdf@,fsa), fsa@,fdsa), fdsa@)
-#   @warn(ASDF), ASDF@,FSA), FSA@,FDSA), FDSA@)
 #   @warn(@)
 #   @warn(1@)
 #   @warn(1@,2@)
@@ -117,37 +143,47 @@ m4_define([b4_warn],
 
 # b4_warn_at(START, END, FORMAT, [ARG1], [ARG2], ...)
 # ---------------------------------------------------
-# Write @warn(START@,END@,FORMAT@,ARG1@,ARG2@,...@) to diversion 0.
+# 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 diversion 0.
+# Write @complain(FORMAT@,ARG1@,ARG2@,...@) to stdout.
 #
-# See the test suite for b4_warn above.
+# 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 diversion 0.
+# 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 diversion 0.
+# Write @fatal(FORMAT@,ARG1@,ARG2@,...@) to stdout and exit.
 #
-# See the test suite for b4_warn above.
+# See b4_warn example.
 m4_define([b4_fatal],
-[b4_error([[fatal]], $@)])
+[b4_error([[fatal]], $@)dnl
+m4_exit(1)])
 
 # b4_fatal_at(START, END, FORMAT, [ARG1], [ARG2], ...)
 # ----------------------------------------------------
-# Write @fatal(START@,END@,FORMAT@,ARG1@,ARG2@,...@) to diversion 0.
+# 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]], $@)])
+[b4_error_at([[fatal]], $@)dnl
+m4_exit(1)])
 
 
 ## ---------------- ##
@@ -176,6 +212,88 @@ 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 rule to reduce with in state S 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 zero, do what YYDEFACT says.
+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.  ##
@@ -214,23 +332,120 @@ m4_define([b4_$3_if],
 # -----------------------------
 # 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([pull])	        # Whether pull parsing is requested.
-b4_define_flag_if([pure])	        # Whether the interface is pure.
-b4_define_flag_if([push])	        # Whether push parsing is requested.
-b4_define_flag_if([use_push_for_pull])  # Whether push parsing should be used
-                                        # in place of pull parsing (where
-                                        # available) for the sake of the test
-                                        # suite.
 b4_define_flag_if([yacc])	        # Whether POSIX Yacc is emulated.
 
 
-## ------------------------- ##
-## Assigning token numbers.  ##
-## ------------------------- ##
+## --------- ##
+## 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([token.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]))])
+
+
+## ------- ##
+## 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]))])
+
 
 
 ## ----------- ##
@@ -248,8 +463,8 @@ 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])])
@@ -285,11 +500,11 @@ b4_define_user_code([pre_prologue])
 b4_define_user_code([stype])
 
 
-# b4_check_user_names(WHAT, USER-LIST, SKELETON-NAMESPACE)
+# b4_check_user_names(WHAT, USER-LIST, BISON-NAMESPACE)
 # --------------------------------------------------------
 # Warn if any name of type WHAT is used by the user (as recorded in USER-LIST)
-# but is not used by the skeleton (as recorded by macros in the namespace
-# SKELETON-NAMESPACE).
+# but is not used by Bison (as recorded by macros in the namespace
+# BISON-NAMESPACE).
 #
 # USER-LIST must expand to a list specifying all grammar occurrences of all
 # names of type WHAT.   Each item in the list must be a triplet specifying one
@@ -304,22 +519,22 @@ b4_define_user_code([stype])
 #               [[[[bar]], [[parser.y:5.7]], [[parser.y:5.16]]]],
 #               [[[[baz]], [[parser.y:8.7]], [[parser.y:8.16]]]]]])
 #
-# The macro SKELETON-NAMESPACE(bar) must be defined iff the name bar of type
-# WHAT is used in the skeleton.  Empty string names are fine, but it would be
-# ugly for a Bison skeleton to actually use one.
+# 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_skeleton_names for SKELETON-NAMESPACE and define
-# that the names bar and baz are used in the skeleton:
+# 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_skeleton_names(bar)])
-#   m4_define([b4_foo_skeleton_names(baz)])
+#   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 SKELETON-NAMESPACE b4_foo_skeleton_names, and with
-# correct quoting:
+# 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_skeleton_names]])
+#                       [[b4_foo_bison_names]])
 m4_define([b4_check_user_names],
 [m4_foreach([b4_occurrence], $2,
 [m4_pushdef([b4_occurrence], b4_occurrence)dnl
@@ -338,59 +553,188 @@ m4_popdef([b4_end])dnl
 
 # b4_percent_define_get(VARIABLE)
 # -------------------------------
-# If the %define variable VARIABLE is defined, emit its value.  Also, record
-# the skeleton's usage of VARIABLE by defining
-# b4_percent_define_skeleton_variables(VARIABLE).
+# Mimic muscle_percent_define_get in ../src/muscle_tab.h exactly.  That is, if
+# the %define variable VARIABLE is defined, emit its value.  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],
-[m4_define([b4_percent_define_skeleton_variables(]$1[)])dnl
+[m4_define([b4_percent_define_bison_variables(]$1[)])dnl
 m4_ifdef([b4_percent_define(]$1[)], [m4_indir([b4_percent_define(]$1[)])])])
 
+# 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([[undefined %%define variable `%s' passed to b4_percent_define_get_loc]], [$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([[undefined %%define variable `%s' passed to b4_percent_define_get_syncline]], [$1])])])
+
 # b4_percent_define_ifdef(VARIABLE, IF-TRUE, [IF-FALSE])
 # ------------------------------------------------------
-# If the %define variable VARIABLE is defined, expand IF-TRUE, else expand
-# IF-FALSE.  Also, record the skeleton's usage of VARIABLE by defining
-# b4_percent_define_skeleton_variables(VARIABLE).
+# 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[)],
-	  [m4_define([b4_percent_define_skeleton_variables(]$1[)])$2],
+	  [m4_define([b4_percent_define_bison_variables(]$1[)])$2],
 	  [$3])])
 
+
+## --------- ##
+## Options.  ##
+## --------- ##
+
+
 # b4_percent_define_flag_if(VARIABLE, IF-TRUE, [IF-FALSE])
 # --------------------------------------------------------
-# If the %define variable VARIABLE is defined to anything but "0" or "false",
-# expand IF-TRUE. If it is defined to "0" or "false", expand IF-FALSE.  If
-# it is undefined, raise an error (this macro should be preceded by
-# b4_percent_define_default).  Also, record the skeleton's usage of VARIABLE by
-# defining b4_percent_define_skeleton_variables(VARIABLE).
+# 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]),
-			          [0], [$3], [false], [$3],
-				  [$2])],
-		         [m4_fatal([invalid %define variable passed to b4_percent_define_flag_if: ]$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([[undefined %%define variable `%s' passed to b4_percent_define_flag_if]], [$1])])])
+
 
 # b4_percent_define_default(VARIABLE, DEFAULT)
 # --------------------------------------------
-# If the %define variable VARIABLE is undefined, set its value to 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])])])
+           [m4_define([b4_percent_define(]$1[)], [$2])dnl
+            m4_define([b4_percent_define_loc(]$1[)],
+                      [[[[<skeleton default value>:-1.-1]],
+                        [[<skeleton default value>:-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], $[2])])
+
+
+# b4_parse_assert_if([IF-ASSERTIONS-ARE-USED], [IF-NOT])
+# b4_parse_trace_if([IF-DEBUG-TRACES-ARE-ENABLED], [IF-NOT])
+# b4_error_verbose_if([IF-ERRORS-ARE-VERBOSE], [IF-NOT])
+# b4_lex_symbol_if([IF-YYLEX-RETURNS-A-COMPLETE-SYMBOL], [IF-NOT])
+# b4_variant_if([IF-VARIANT-ARE-USED], [IF-NOT])
+# ----------------------------------------------
+b4_percent_define_if_define([error_verbose])
+b4_percent_define_if_define([lex_symbol])
+b4_percent_define_if_define([locations])     # Whether locations are tracked.
+b4_percent_define_if_define([parse.assert])
+b4_percent_define_if_define([parse.trace])
+b4_percent_define_if_define([variant])
+
+
+
+# b4_percent_define_check_values(VALUES)
+# --------------------------------------
+# Mimic muscle_percent_define_check_values in ../src/muscle_tab.h exactly
+# except that the VALUES structure is more appropriate for M4.  That is, VALUES
+# is a list of sublists of strings.  For each sublist, the first string is the
+# name of a %define variable, and all remaining strings in that sublist are the
+# valid values for that variable.  Complain if such a variable is undefined (a
+# Bison error since the default value should have been set already) or defined
+# to any other value (possibly a user error).  Don't record this as a Bison
+# usage of the variable as there's no reason to suspect that the value has yet
+# influenced the output.
+#
+# For example:
+#
+#   b4_percent_define_check_values([[[[foo]], [[foo-value1]], [[foo-value2]]]],
+#                                  [[[[bar]], [[bar-value1]]]])
+m4_define([b4_percent_define_check_values],
+[m4_foreach([b4_sublist], m4_quote($@),
+            [_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[)])))])dnl
+   m4_popdef([b4_good_value])],
+  [b4_fatal([[undefined %%define variable `%s' passed to b4_percent_define_check_values]], [$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
-# the skeleton's usage of QUALIFIER (if specified) by defining
-# b4_percent_code_skeleton_qualifiers(QUALIFIER).
+# 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:
@@ -399,10 +743,10 @@ m4_define([b4_percent_define_default],
 #   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_skeleton_qualifiers(]$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.]])
+                   [["%code ]$1["]])[ blocks.]])
 b4_user_code([m4_indir(b4_macro_name)])
 ])dnl
 m4_popdef([b4_macro_name])])
@@ -411,26 +755,33 @@ m4_popdef([b4_macro_name])])
 # -----------------------------------------------------
 # 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 the skeleton's usage of QUALIFIER (if specified) by defining
-# b4_percent_code_skeleton_qualifiers(QUALIFIER).
+# 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_skeleton_qualifiers(]$1[)])])$2],
+          [m4_ifval([$1], [m4_define([b4_percent_code_bison_qualifiers(]$1[)])])$2],
 	  [$3])])
 
 
-## --------------------------------------------------------- ##
-## After processing the skeletons, check that all the user's ##
-## %define variables and %code qualifiers were used.         ##
-## --------------------------------------------------------- ##
+# Default values for %define.
+# ---------------------------
+# If the %token.prefix, it is empty.
+m4_percent_define_default([[token.prefix]], [[]])
+
+
+
+## ----------------------------------------------------------- ##
+## 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[_skeleton_]$2[s]])])])
+                               [[b4_percent_]$1[_bison_]$2[s]])])])
 
-m4_wrap([
+m4_wrap_lifo([
 b4_check_user_names_wrap([[define]], [[variable]])
 b4_check_user_names_wrap([[code]], [[qualifier]])
 ])