C++ variadic template template argument that matches any kind of parameters

Question

I was wondering if it\'s possible to write a template function that can take any other arbitrary template as a parameter and properly match the template name (i.e. not just the

Answer 1

You must have a metafunction that rebinds the type of container. Because you cannot just replace first template parameter:

vector > input;
vector > just_replaced;
vector > properly_rebound;

So, just write such a metafunction for known set of containers.

template class rebinder;

// example for vectors with standard allocator
template class rebinder< std::vector, T > {
public:
  typedef std::vector type;
};
// example for lists with arbitrary allocator
template class rebinder< std::list, T > {
  typedef typename A::template rebind::other AT; // rebind the allocator
public:
  typedef std::list type; // rebind the list
};
// example for arrays
template class rebinder< std::array, T > {
public:
  typedef std::array type;
};

Rules of rebinding may vary for different containers.

Also you might require a metafunction that extracts value type from arbitrary container, not only std-conformant (typedef *unspecified* value_type)

template class get_value_type {
public:
  typedef typename Container::value_type type; // common implementation
};
template class get_value_type< YourTrickyContainer > {
  ......
public:
  typedef YZ type;
};