+[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([[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])
+# ------------------------------------------------------
+# 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_bison_variables(]$1[)])$2],
+ [$3])])
+
+# 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([[undefined %%define variable `%s' passed to b4_percent_define_flag_if]], [$1])])])