allow to compare tuple of two elements and pair

alib2std/src/extensions/container/tuple.hpp

@@ -237,6 +237,16 @@ struct tuple_element < I, ext::tuple < Types... > > {
 	typedef typename std::tuple_element < I, std::tuple < Types ... > >::type type;
 };
+template < class T1, class T2, class T3, class T4 >
+inline constexpr bool operator < ( const std::pair < T1, T2 > & first, const std::tuple < T3, T4 > & second ) {
+	return std::tie ( first.first, first.second ) < second;
+}
+
+template < class T1, class T2, class T3, class T4 >
+inline constexpr bool operator < ( const std::tuple < T1, T2 > & first, const std::pair < T3, T4 > & second ) {
+	return first < std::tie ( second.first, second.second ) ;
+}
+
 } /* namespace ext */
 #endif /* __TUPLE_HPP_ */