gistfile1.txt

#include <iostream>

struct Point
{
public:
    double x,y,z;
};

// A mixin to add an 'A' value to a point
template<class Base>
class A : public Base
{
public:
    template <typename T_RHS>
    A& operator=( const T_RHS& rhs )
    {
        Base::operator=(rhs);
    }

    double a;
};

int main()
{
  Point point;

  A<Point> aPoint = point;

  return 0;
}