"Using" declaration with scope only on current class?

Question

Is there a possibility to have a using directive whose scope is limited to a single class?

Note, that what I want to "use" is not contained in the parent of the current class.

For simplicity, assume the following exmple:

#include<vector>

class foo
{
using std::vector; //Error, a class-qualified name is required
}

Another interesting thing to know is, if the using directives are included, if a header is included:

MyClassFoo.h:
#include<vector>

using std::vector; //OK
class foo
{

}

And in

NewHeader.h
#include "MyClassFoo.h"
...

how can I prevent "using std::vector" to be visible here?

Sobersided

Is there a possibility to create a templated type alias for "std::vector<T>" that is then called "vector"? That way it'd do the same as what I want the using std::vector to do inside the class – Sobersided

Yes, using declarations can be templated when creating type aliases, and it's okay to call that type alias vector since it's in another scope from std::vector. – Admixture

I think it's worth pointing out that this isn't a using directive, it's a using declaration. Using directives introduce namespaces. – Crinoline

thanks, and I changed the "directive" to "declaration" – Sobersided

Close to what you want using a wrapper namespace. – Clements

Answer 1

Since you tagged c++11:

#include<vector>

class foo
{
  template<typename T>
  using vector = std::vector<T>;
};

Kodok

Also, template<class T, class... Args> using vector = std::vector<T, Args...>; if you ever have any inclination of using the optional allocator. – Swatch

This looks, good, but unfortunately it gives me "unrecognizable template declaration/definition"?! – Sobersided

@Sobersided You need to compile with -std=c++11 with a recent enough compiler – Kodok

Since I'm compiling with C++11, it's a problem of VS2012 -> link to supported VS C++11 features – Sobersided

@Sobersided Yep seems it was introduced in VS2013: msdn.microsoft.com/en-us/library/vstudio/dn467695.aspx, sad =/ – Kodok

Answer 2

As for your first requirement, you can use a namespace so that the scope of using namespace is limited to a single class.

#include<vector>

namespace FooClasses
{
    using namespace std; //The scope of this statement will NOT go outside this namespace.

    class foo
    {
      vector<int> vecIntVector; 
    };

}// namespace FooClasses

For your second case, do make use of #define and #undef wisely.

Insanity