+void ProgramParser::preprocess_version()
+{
+ expect("version");
+ string token = parse_token();
+ unsigned version = lexical_cast<unsigned>(token);
+ cur_stage->required_version = Version(version/100, version%100);
+
+ token = parse_token();
+ if(!token.empty())
+ throw runtime_error(format_syntax_error("end of line"));
+}
+