[C++-sig] python override of C++ virtual mem fun not exactly working yet

[DRandallTaylor]

Hello again.  n00b here.
Simple problem, but hard for me, cause I'm n00b.

My Python class derives from a C++ class and overrides a virtual mem fun that 
has an implementation.  In the derived Python class, I need "self" to be 
treated polymorphically with respect to the C++ base class.  The boost::python 
Tutorial gives a sample but the derivation shown of BaseWrap is private, not 
public derivation:  "struct BaseWrap : Base, wrapper<Base>".  I know this is a 
simple problem... but having trouble with it...

My error msg tells me that my 2nd arg is a InboxListener not a Callback.


  File "test.py", line 9, in __init__
    self.inbox = sess.CreateInbox(self)
ArgumentError: Python argument types in
    Session.CreateInbox(Session, InboxListener)
did not match C++ signature:
    CreateInbox(class Session {lvalue}, class Callback {lvalue})


My C++ stuff:


class CallbackWrap : public Callback, python::wrapper<Callback>
{  public:
    void OnData() // iff public derivation used, then this is virtual; else 
non-virtual
    {
        if (python::override the_override = this->get_override("OnData"))
            the_override();
        else  Callback::OnData();
    }
    void default_OnData() { this->Callback::OnData(); }    
};


python::class_ < CallbackWrap, boost::noncopyable > ("Callback")
.def("OnData", &Callback::OnData, &CallbackWrap::default_OnData);


python::class_<Session>("Session")
.def("CreateInbox", &Session::CreateInbox, python::return_value_policy< 
python::return_by_value >());


And my Python stuff:


class InboxListener(Callback):
	def __init__(self, session):
		self.inbox = session.CreateInbox(self)
	def OnData():
		print "OnData called"
		return


Seems like "self" passed to  session.CreateInbox should be treated as a 
Callback type, since I've used public derivatation.  Can you help me spot the 
error of my ways?  And I thank you!

DRandallTaylor