[C++-sig] pyste: current cvs/1_30_00 difference in treatment of overloaded members

[Nicodemus]

Paul Rudin wrote:

>Hi,
>
>I've noticed a difference between the c++ generated by the current cvs and the 1_30_00 released version.
>Here's an illustration:
>

Thanks for the report Rubin! I found the problem, but now a doubt came 
up about how to properly export protected (and even private) methods.

Suppose:

class A
{
public:
    const char* get_name() { return name(); }

protected:
    virtual const char* name() { return "foo"; }
};
 


Here's the wrapper generated by pyste now:


struct A_Wrapper: A
{
    A_Wrapper(PyObject* self_, const A & p0):
        A(p0), self(self_) {}

    A_Wrapper(PyObject* self_):
        A(), self(self_) {}

    const char * name() {
        return call_method< const char * >(self, "name");
    }

    PyObject* self;
};


BOOST_PYTHON_MODULE(test)
{
    class_< A, A_Wrapper >("A", init<  >())
        .def(init< const A & >())
        .def("get_name", &A::get_name)
    ;

}


Now from Python:

 >>> from test import *
 >>> a = A()
 >>> a.get_name()
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
AttributeError: 'A' object has no attribute 'name'
 >>>

Sure: get_name is called in C++, which calls the *overriden* "name" in 
A_Wrapper, but the Python object doesn't have this function. Even 
thought the protected method "name" has a default implementation, this 
is not passed to Boost.Python at all. It couldn't be declared like any 
public virtual function in the class_ definition (hence passsing also 
its default implementation), because A::name is protected and can't be 
accessed by outside code. So how to export default implementations of 
protected virtual methods?