How-to nest multiple submodules

[Sewtz]

I am working on a larger Framework in C++ which is divided into several namespaces like

namespace Framework::ModA{
   /* ModA stuff */
}

namespace Framework::ModB{
  /* ModB stuff */
}

Now I want to recreate such a structure in my python bindings. How can I achieve a structure like

import Framework.ModA
import Framework.ModB

[jiwaszki]

Hi @Sewtz , I assume you want pure pybind solution. Here it is:

#include <pybind11/pybind11.h>

namespace py = pybind11;

size_t free_function() {
      return 42;
}

namespace module_a {
      size_t func() {
            return 97;
      }
}

namespace module_b {
      size_t func() {
            return 20;
      }
}

PYBIND11_MODULE(mymodule, m)
{
      m.doc() = "This is top module - mymodule.";
      m.def("free_function", &free_function);

      auto m_a = m.def_submodule("module_a", "This is A.");
      m_a.def("func", &module_a::func);

      auto m_b = m.def_submodule("module_b", "This is B.");
      m_b.def("func", &module_b::func);
}

You can either go with this pure pybind code and register submodules according to names of your namespaces (you can chain them as well) or register modules and re-arrange them with init files.

So this is it, for example you can look up submodules in terminal using help:

Help on module mymodule:

NAME
    mymodule - This is top module - mymodule.

SUBMODULES
    module_a  <-- A is here
    module_b  <-- B is here

FUNCTIONS
    free_function(...) method of builtins.PyCapsule instance
        free_function() -> int

[Sewtz]

Thank you

That's what I needed.

[The9Cat]

@jiwaszki I hope you don't mind that I'm asking a question about your example. There is something that has puzzled me for a bit.

The line

auto m_a = m.def_submodule("module_a", "This is A.");

defines a docstring for the submodule. But running help as in the example above does not print the docstring, it just lists the module by name. And it's not printed in help(mymodule.module_a) either. What is this submodule docstring for?