Index: src/Common/utility.h
===================================================================
--- src/Common/utility.h	(revision d30790faa8c3aa02f02c5d71926705f7e2dc2f94)
+++ src/Common/utility.h	(revision 0555f4bcb3f9d01c36c8df66c8417c065804176b)
@@ -144,7 +144,18 @@
 
 template < typename T >
-std::string toString ( T value ) {
+void toString_single ( std::ostream & os, const T & value ) {
+	os << value;
+}
+
+template < typename T, typename... Params >
+void toString_single ( std::ostream & os, const T & value, const Params & ... params ) {
+	os << value;
+	toString_single( os, params ... );
+}
+
+template < typename ... Params >
+std::string toString ( const Params & ... params ) {
 	std::ostringstream os;
-	os << value; // << std::ends;
+	toString_single( os, params... );
 	return os.str();
 }
@@ -218,4 +229,21 @@
 }
 
+template< typename T >
+void warn_single( const T & arg ) {
+	std::cerr << arg << std::endl;
+}
+
+template< typename T, typename... Params >
+void warn_single(const T & arg, const Params & ... params ) {
+	std::cerr << arg;
+	warn_single( params... );
+}
+
+template< typename... Params >
+void warn( const Params & ... params ) {
+	std::cerr << "Warning: ";
+	warn_single( params... );
+}
+
 #endif // _UTILITY_H