+
+m4_pushdef([b4_copyright_years],
+ [2002, 2003, 2004, 2005, 2006, 2007, 2008])
+
+# How the semantic value is extracted when using variants.
+b4_variant_if([
+ # b4_symbol_value(VAL, [TYPE])
+ # ----------------------------
+ m4_define([b4_symbol_value],
+ [m4_ifval([$2],
+ [$1.as<$2>()],
+ [$1])])
+]) # b4_variant_if
+
+
+# b4_symbol_actions(FILENAME, LINENO,
+# SYMBOL-TAG, SYMBOL-NUM,
+# SYMBOL-ACTION, SYMBOL-TYPENAME)
+# -------------------------------------------------
+# Same as in C, but using references instead of pointers.
+m4_define([b4_symbol_actions],
+[m4_pushdef([b4_dollar_dollar],
+ [b4_symbol_value([yyvalue], [$6])])dnl
+m4_pushdef([b4_at_dollar], [yylocation])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_symbol_action_(SYMBOL-TAG, SYMBOL-NUM, SYMBOL-TYPENAME)
+# ----------------------------------------------------------
+# Invoke b4_dollar_dollar(SYMBOL_TYPENAME) for each symbol.
+m4_define([b4_symbol_action_],
+[m4_ifval($3,
+[ case $2: // $1
+ b4_dollar_dollar($@);
+ break;
+])])
+
+
+# b4_symbol_variant(YYTYPE, YYVAL, ACTION)
+# ----------------------------------------
+# Run some ACTION ("build", or "destroy") on YYVAL of symbol type
+# YYTYPE.
+m4_define([b4_symbol_variant],
+[m4_pushdef([b4_dollar_dollar],
+ [$2.$3<$][3>()])dnl
+ switch ($1)
+ {
+m4_map([b4_symbol_action_], m4_defn([b4_type_names]))
+ default:
+ break;
+ }
+m4_popdef([b4_dollar_dollar])dnl
+])
+
+
+# _b4_char_sizeof_counter
+# -----------------------
+# A counter used by _b4_char_sizeof_dummy to create fresh symbols.
+m4_define([_b4_char_sizeof_counter],
+[0])
+
+# _b4_char_sizeof_dummy
+# ---------------------
+# At each call return a new C++ identifier.
+m4_define([_b4_char_sizeof_dummy],
+[m4_define([_b4_char_sizeof_counter], m4_incr(_b4_char_sizeof_counter))dnl
+dummy[]_b4_char_sizeof_counter])
+
+
+# b4_char_sizeof(SYMBOL-TAG, SYMBOL-NUM, SYMBOL-TYPENAME)
+# -------------------------------------------------------
+# To be mapped on the list of type names to produce:
+#
+# char dummy1[sizeof(type_name_1)];
+# char dummy2[sizeof(type_name_2)];
+#
+# for defined type names.
+# $3 is doubly-quoted, do not quote it again.
+m4_define([b4_char_sizeof],
+[m4_ifval($3,
+[
+ char _b4_char_sizeof_dummy@{sizeof($3)@}; // $1])dnl
+])
+
+
+m4_define([b4_parser_class_name],
+ [b4_percent_define_get([[parser_class_name]])])
+
+# The header is mandatory.
+b4_defines_if([],
+ [b4_fatal([b4_skeleton[: using %%defines is mandatory]])])
+