diff --git a/include/raii/string_base.hpp b/include/raii/string_base.hpp
index 21b0279..66f9251 100644
--- a/include/raii/string_base.hpp
+++ b/include/raii/string_base.hpp
@@ -145,9 +145,7 @@ namespace raii{
 
 		string_intermediary& operator=(const string_intermediary& s){
 			string_intermediary tmp(s);
-			std::swap(m_data, tmp.m_data);
-			m_length = tmp.m_length;
-			return *this;
+			return (*this = std::move(tmp));
 		}
 		string_intermediary& operator=(string_intermediary&& s){
 			std::swap(m_data, s.m_data);
@@ -290,16 +288,15 @@ namespace raii{
 		Right m_r;
 
 	public:
-		template<class T, class U>
-		constexpr string_cat_expr(T&& l, U&& r):
+		constexpr string_cat_expr(Left l, Right r):
 			m_l(std::forward<Left>(l)),
 			m_r(std::forward<Right>(r)){}
 		constexpr string_cat_expr(const string_cat_expr& s):
-			m_l(s.m_l),
-			m_r(s.m_r){}
+			m_l(std::forward<Left>(s.m_l)),
+			m_r(std::forward<Right>(s.m_r)){}
 		constexpr string_cat_expr(string_cat_expr&& s):
-			m_l(s.m_l),
-			m_r(s.m_r){}
+			m_l(std::forward<Left>(s.m_l)),
+			m_r(std::forward<Right>(s.m_r)){}
 
 		constexpr size_t length(void)const{
 			return _llen() + _rlen();
@@ -360,18 +357,69 @@ bool operator!=(Str1&& left, Str2&& right){
 	return !(left == right);
 }
 
-template<class Right, typename std::enable_if<raii::detail::is_string<Right>::value,void>::type* = nullptr>
+template<class Right, typename std::enable_if<raii::detail::is_string<Right>::value && std::is_rvalue_reference<Right&&>::value,void>::type* = nullptr>
+constexpr auto operator+(const char* left, Right&& right){
+	return raii::string_cat_expr<const char*,typename std::remove_reference<Right>::type>(left, std::move(right));
+}
+template<class Right, typename std::enable_if<raii::detail::is_string<Right>::value && !std::is_rvalue_reference<Right&&>::value,void>::type* = nullptr>
 constexpr auto operator+(const char* left, Right&& right){
 	return raii::string_cat_expr<const char*,decltype(std::forward<Right>(right))>(left, std::forward<Right>(right));
 }
-template<class Left, typename std::enable_if<raii::detail::is_string<Left>::value,void>::type* = nullptr>
+
+template<class Left, typename std::enable_if<raii::detail::is_string<Left>::value && std::is_rvalue_reference<Left&&>::value,void>::type* = nullptr>
+constexpr auto operator+(Left&& left, const char* right){
+	return raii::string_cat_expr<typename std::remove_reference<Left>::type,const char*>(std::move(left), right);
+}
+template<class Left, typename std::enable_if<raii::detail::is_string<Left>::value && !std::is_rvalue_reference<Left&&>::value,void>::type* = nullptr>
 constexpr auto operator+(Left&& left, const char* right){
 	return raii::string_cat_expr<decltype(std::forward<Left>(left)),const char*>(std::forward<Left>(left), right);
 }
-template<class Left, class Right, typename std::enable_if<raii::detail::is_string<Left>::value&&raii::detail::is_string<Right>::value,void>::type* = nullptr>
+
+template<class Left,
+         class Right,
+         typename std::enable_if<
+         	raii::detail::is_string<Left>::value &&
+         	raii::detail::is_string<Right>::value &&
+         	std::is_rvalue_reference<Left&&>::value &&
+         	std::is_rvalue_reference<Right&&>::value,
+         void>::type* = nullptr>
+constexpr auto operator+(Left&& l, Right&& r){
+	return raii::string_cat_expr<typename std::remove_reference<Left>::type,typename std::remove_reference<Right>::type>(std::move(l), std::move(r));
+}
+template<class Left,
+         class Right,
+         typename std::enable_if<
+         	raii::detail::is_string<Left>::value &&
+         	raii::detail::is_string<Right>::value &&
+         	!std::is_rvalue_reference<Left&&>::value &&
+         	!std::is_rvalue_reference<Right&&>::value,
+         void>::type* = nullptr>
 constexpr auto operator+(Left&& l, Right&& r){
 	return raii::string_cat_expr<decltype(std::forward<Left>(l)),decltype(std::forward<Right>(r))>(std::forward<Left>(l), std::forward<Right>(r));
 }
+template<class Left,
+         class Right,
+         typename std::enable_if<
+         	raii::detail::is_string<Left>::value &&
+         	raii::detail::is_string<Right>::value &&
+         	std::is_rvalue_reference<Left&&>::value &&
+         	!std::is_rvalue_reference<Right&&>::value,
+         void>::type* = nullptr>
+constexpr auto operator+(Left&& l, Right&& r){
+	return raii::string_cat_expr<typename std::remove_reference<Left>::type,decltype(std::forward<Right>(r))>(std::move(l), std::forward<Right>(r));
+}
+template<class Left,
+         class Right,
+         typename std::enable_if<
+         	raii::detail::is_string<Left>::value &&
+         	raii::detail::is_string<Right>::value &&
+         	!std::is_rvalue_reference<Left&&>::value &&
+         	std::is_rvalue_reference<Right&&>::value,
+         void>::type* = nullptr>
+constexpr auto operator+(Left&& l, Right&& r){
+	return raii::string_cat_expr<decltype(std::forward<Left>(l)),typename std::remove_reference<Right>::type>(std::forward<Left>(l), std::move(r));
+}
+
 template<class Left, class Right, typename std::enable_if<raii::detail::is_string<Left>::value&&raii::detail::is_string<Right>::value,void>::type* = nullptr>
 decltype(auto) operator+=(Left& l, Right&& r){
 	return l = (l + std::forward<Right>(r));