[C++-sig] Instantiating a Python class from C++?

[Pierre Barbier de Reuille]

I will suppose you have access to the module namespace containing the 
derived class. I'll call this "module_namespace". So, you can retrieve 
the class using Boost.Python very simply :

boost::python::object cls = module_namespace["DerivedClass"]

And now, you can create the object with :

boost::python::object obj = cls();

And to get a pointer to the underlying C++ object :

MyClass* cpp_obj = extract<MyClass*>(obj);

It should work ...

Pierre

Peter a écrit :
> Another question, and I really hope this doesn't get emailed four
> idnetical times like my last question.  My sincere apologies in advance
> if it does.
> 
> I have a C++ class with a virtual function that I want overridden in
> Python.  I expose it to Python in the normal way:
> 
>   class_<MyClass>("CPP_Class", no_init)
>     .def("vfunc", &MyClass::func);  
> 
> And in Python the user derives from this class overrides the virtual
> method, e.g.:
> 
>   class DerivedClass(CPP_Class):
>       def vfunc(self):
>           #do stuff in Python
> 
> I want to create an instance of "DerivedClass" from C++ and assign it to
> the base class ptr and then call the overridden Python function via the
> virtual fn defined in the C++ base class.  So my question is; how do I,
> from C++, create this instance of DerivedClass (assuming I know that the
> user called it DerivedClass)?
> 
> Thank you very much for any help,
> Peter
> 
> 
> 
> 
> 
> 
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-- 
Pierre Barbier de Reuille

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