[boost] returning actual class type to python

From: Eric van Riet Paap (eric_at_[hidden])
Date: 2002-04-04 06:48:39

In C++ I have a class Node, Derived1 and Derived2, where I would like Node
to return a pointer to the actual derived instance.
I now have to cumbersome construct where the C++ return a pointer to a Node
and the Python code calls another function of
the Node class to get the correct derived class. Like so...

//Node.h
class Node
{
 static Node*   Self    (void)      { return (Node*)gpCNode; } //use
Node.As...() or Global_.Instance() to convert it to the correct
class-type!!!
 Camera   *    AsCamera   (void)      { return (Camera   *)this; }
//class-type convertion
 Mesh     *    AsMesh    (void)      { return (Mesh     *)this; }
//class-type convertion
 Light    *    AsLight    (void)      { return (Light    *)this; }
//class-type convertion
};

//Global_.py
def Instance(node):
         return eval('node.As'+node.SuperClassName()+'()')

What I would like to do is let the Node.Self() function return the corrent
type but I'm not actacly sure how to proceed.
I can think of two ways. The first one would be to return a PyObject and
building that in the Self function, which is something
I have never toyed with. The second one would be to use a virtual function
where all derived classes return the actual type,
but I'm not sure the actual type pointer will be return to python in this
case, which is something I will try to find out now.

Is my above text understandable and does anyone have tips or an example
perhaps?

kind regards,
Eric van Riet Paap
Utrecht, The Netherlands