Base class in a submodule, derived class in some other submodule.

[andre-caldas]

I have a module A. It has two submodules: S and T.

To make things more complicated, each module is defined in a different cpp translation unit:

NB_MODULE(paracadis, m) {
  m.doc() = "ParaCADis python interface.";
  init_naming_scheme(m);
  init_geometric_primitives(m);
  init_document_tree(m);
}

Each method called above creates a submodule. Many classes in geometric_primitives derive from a class in naming_scheme. Because they are all "something with a name". :-)

Speaking in more abstract terms, in A.S I have a "base class":

  nb::class_<BaseClass>(S, "BaseClass");

In A.T, I have a class derived from BaseClass:

  // Does not seem to work.
  nb::class_<DerivedClass, BaseClass>(T, "DerivedClass");
  // Maybe, something like this... but where do I get `b` from?
  nb::class_<DerivedClass>(T, "DerivedClass", b);

What would be the correct way to setup bindings for DerivedClass?

[wjakob]

I think that should be supported. You can give a Python object to nb::class_ to use as base, and you can use nb::module_::import_("..").attr("..") to fetch that object. Please refer to the documentation, this case is explained there somewhere.

[andre-caldas]

Dear professor,

Thank you very much for your help and patience. :-)

I thought you would like the feedback... so here is the implemented solution:
https://github.com/andre-caldas/ParaCADis/blob/016f10e3d572dd7105bf30103fdc5aa02e356d9a/src/base/geometric_primitives/python_bindings/module.cpp#L46