Bindings for copy constructors for classes with Python call-back structure

[lyskov]

Hi Wenzel, I noticed that attempt to bind copy constructors for classes that binded though Python call-back structure (like example12) gives a compilation error. However changing constructor argument type from original class to type-of-call-back structure fixes the error. Is this expect behavior? If so, then perhaps it is a good idea to mention this in docs?

Here is code for modified init_ex12 from PyBind11 example12 to demonstrate this issue. Uncommenting the line .def(py::init<Example12 const &>()) (and commenting out .def(py::init<PyExample12 const &>())) will lead to a compilation error. (rest of example12 code is unchanged)

void init_ex12(py::module &m) {
    /* Important: use the wrapper type as a template
       argument to class_<>, but use the original name
       to denote the type */
    py::class_<PyExample12>(m, "Example12")
        /* Declare that 'PyExample12' is really an alias for the original type 'Example12' */
        .alias<Example12>()
        .def(py::init<int>())

        //.def(py::init<Example12 const &>()) // give compilation error
        .def(py::init<PyExample12 const &>()) // works fine


        /* Reference original class in function definitions */
        .def("run", &Example12::run)
        .def("run_bool", &Example12::run_bool)
        .def("pure_virtual", &Example12::pure_virtual);

    m.def("runExample12", &runExample12);
    m.def("runExample12Bool", &runExample12Bool);
    m.def("runExample12Virtual", &runExample12Virtual);
}

Thanks,

[wjakob]

Yep, it should be PyExample12. I'll commit the copy constructor to the example.