+
+template<typename T>
+struct RemoveConstReference
+{ typedef typename RemoveConst<typename RemoveReference<T>::Type>::Type Type; };
+
+
+template<bool c, typename R>
+struct EnableIf;
+
+template<typename R>
+struct EnableIf<true, R>
+{ typedef R Yes; };
+
+template<typename R>
+struct EnableIf<false, R>
+{ typedef R No; };
+
+
+/**
+Common fragments used in SFINAE-based decider constructs.
+*/
+struct Sfinae
+{
+ struct Yes { char c[2]; };
+ struct No { char c; };
+
+ template<typename T>
+ static No f(...);
+
+ template<typename C, typename T>
+ struct Evaluate
+ {
+ enum { value = (sizeof(C::template f<T>(0))==sizeof(Yes)) };
+ };
+};
+