您应该如何为自定义类实现STL功能？

Question

I'm implementing a tuple-like class, call it MyTuple , and I would like it to have some STL features, namely tuple_element , tuple_size , and get .

1. Should I implement tuple_element and tuple_size specializations in namespace std ? If not then how should I implement them?
2. Since I'm not allowed to overload the STL get function, does that mean I must provide a separate get function in my own namespace, thereby forcing users to write using std::get; ?

Answer 1

Recall that there ain't no such thing as a partial specialization of function templates. So you can't partially specialize std::tuple_element et al for your class.

Normally, you would define free-standing functions that are logically part of your class' interface in the same namespace as the class itself. Then you can rely on argument-dependent lookup to find them. std::get would be found by that same mechanism - users of your library will not in fact be forced to write using std::get .