+]])[
+
+# Hijack the initial action to initialize the locations.
+]b4_bison_locations_if([m4_define([b4_initial_action],
+[yylloc.initialize ();]m4_ifdef([b4_initial_action], [
+m4_defn([b4_initial_action])]))])[
+
+# Hijack the post prologue to insert early definition of YYLLOC_DEFAULT
+# and declaration of yyerror.
+]m4_append([b4_post_prologue],
+[b4_syncline([@oline@], [@ofile@])[
+]b4_yylloc_default_define[
+#define YYRHSLOC(Rhs, K) ((Rhs)[K].yystate.yyloc)
+]b4_function_declare([yyerror],
+ [static void],b4_locations_if([
+ [[const ]b4_namespace_ref::b4_parser_class_name[::location_type *yylocationp],
+ [yylocationp]],])
+ b4_parse_param,
+ [[const char* msg], [msg]])])
+
+
+#undef yynerrs
+#undef yychar
+#undef yylval]b4_locations_if([
+#undef yylloc])
+
+m4_if(b4_prefix, [yy], [],
+[[/* Substitute the variable and function names. */
+#define yyparse ]b4_prefix[parse
+#define yylex ]b4_prefix[lex
+#define yyerror ]b4_prefix[error
+#define yydebug ]b4_prefix[debug
+]]b4_pure_if([], [[
+#define yylval ]b4_prefix[lval
+#define yychar ]b4_prefix[char
+#define yynerrs ]b4_prefix[nerrs]b4_locations_if([[
+#define yylloc ]b4_prefix[lloc]])]))
+
+# Hijack the epilogue to define implementations (yyerror, parser member
+# functions etc.).
+m4_append([b4_epilogue],
+[b4_syncline([@oline@], [@ofile@])[