pass tokens by reference in DataFactory

alib2data/src/factory/DataFactory.hpp

@@ -72,7 +72,7 @@ public:
 	 * @return parsed String
 	 */
 	template<class T>
-	static T fromTokens(std::list<sax::Token> tokens) {
+	static T fromTokens(std::list<sax::Token>& tokens) {
 		if(tokens.size() == 0) throw exception::AlibException("Empty tokens list");
 		if(alib::api<exception::AlibException>::first(tokens)) throw alib::api<exception::AlibException>::parse(tokens);