boost::python Export Custom Exception

Question

I am currently writing a C++ extension for Python using Boost.Python. A function in this extension may generate an exception containing information about the error (beyond

Answer 1

Thanks to variadic templates and generalized lambda capture, we can collapse Jack Edmond's answer into something much more manageable and hide all of the cruft from the user:

template 
py::class_ exception_(Args&&... args) {
    py::class_ cls(std::forward(args)...);
    py::register_exception_translator([ptr=cls.ptr()](E const& e){
        PyErr_SetObject(ptr, py::object(e).ptr());
    });
    return cls;
}

To expose MyCPPException as an exception, you just need to change py::class_ in the bindings to exception_:

exception_("MyCPPException", py::init())
    .add_property("message", &MyCPPException::getMessage)
    .add_property("extra_data", &MyCPPException::getExtraData)
;

And now we're back to the niceties of Boost.Python: don't need to name the class_ instance, don't need this extra PyObject*, and don't need an extra function somewhere.