Updated swizzle implementation, assert and static_assert draft

glm/core/type_vec4.hpp

@@ -36,6 +36,7 @@ namespace glm
 		struct tvec4
 		{
 			enum ctor{null};
+			enum {_size = 4};
 			typedef T value_type;
 			typedef std::size_t size_type;
 			static size_type value_size();

glm/gtc/swizzle.hpp

@@ -26,9 +26,9 @@ namespace glm
 	//! GLM_GTC_swizzle extension
 	namespace swizzle{
 
-		template <typename T>
+		template <typename T, template <typename> class vecType>
 		T swizzle(	
-			detail::tvec4<T> const & v,
+			vecType<T> const & v,
 			comp x);
 
 		template <typename T>
@@ -46,6 +46,21 @@ namespace glm
 			detail::tvec4<T> const & v,
 			comp x, comp y, comp z, comp w);
 
+		template <typename T>
+		T& swizzle(
+			detail::tvec4<T> & v,
+			comp x);
+
+		template <typename T>
+		detail::tref2<T> swizzle(
+			detail::tvec4<T> & v,
+			comp x, comp y);
+
+		template <typename T>
+		detail::tref3<T> swizzle(
+			detail::tvec4<T> & v,
+			comp x, comp y, comp z);
+
 		template <typename T>
 		detail::tref4<T> swizzle(
 			detail::tvec4<T> & v,

glm/gtc/swizzle.inl

@@ -2,13 +2,14 @@ namespace glm{
 namespace gtc{
 namespace swizzle
 {
-	template <typename T>
+	template <typename T, template <typename> class vecType>
 	inline T swizzle
 	(	
-		detail::tvec4<T> const & v,
+		vecType<T> const & v,
 		comp x
 	)
 	{
+		assert(int(x) < int(typename vecType<T>::_size));
 		return v[x];
 	}