add all same type trait

alib2std/src/extensions/type_traits.hpp

@@ -104,6 +104,20 @@ namespace std {
 		typedef typename match_cv_ref_rec < Ref, typename decay < Type >::type >::type type;
 	};
+// ----------------------------------------------------------------------------------------------------
+
+	template < typename ... T >
+	struct all_same : std::false_type { };
+
+	template < >
+	struct all_same < > : std::true_type { };
+
+	template < typename T >
+	struct all_same < T > : std::true_type { };
+
+	template < typename T, typename ... Ts >
+	struct all_same < T, T, Ts ... > : all_same < T, Ts ... > { };
+
 } /* namespace std */
 #endif /* __TYPE_TRAITS_HPP_ */