Python: Generate function stubs from C module

Question

I made a Python module in C/C++ with Python C API. I use setuptools.Extension in my setup.py.

It creates one .py file which loads a python module from some compiled .pyd file:

def __bootstrap__():
    global __bootstrap__, __loader__, __file__
    import sys, pkg_resources, imp
    __file__ = pkg_resources.resource_filename(__name__, 'zroya.cp36-win32.pyd')
    __loader__ = None; del __bootstrap__, __loader__
    imp.load_dynamic(__name__,__file__)
__bootstrap__()

But it does not generate python stubs for IDE autocomplete feature. I would like all exported functions and classes to be visible from .py file:

def myfunction_stub(*args, **kwargs):
    """
    ... function docstring
    """
    pass

Is it possible? Or do I have to create some python "preprocessor" which loads data from .pyd file and generate stubs with docstrings?

Source code is available on github.

Answer 1

Unfortunately, mypy's stubgen does not (yet) include docstrings and signatures. However, it is relatively easy to automatically generate your own stub's using the Python native inspect package. For example, I use something along the lines of:

import my_package
import inspect

with open('my_package.pyi', 'w') as f:
    for name, obj in inspect.getmembers(nf):
        if inspect.isclass(obj):
            f.write('\n')
            f.write(f'class {name}:\n')

            for func_name, func in inspect.getmembers(obj):
                if not func_name.startswith('__'):
                    try:
                        f.write(f'    def {func_name} {inspect.signature(func)}:\n')
                    except:
                        f.write(f'    def {func_name} (self, *args, **kwargs):\n')
                    f.write(f"      '''{func.__doc__}'''")
                    f.write('\n    ...\n')

So essentially, first install your package and afterwards you can run this script to create a .pyi. You can change it easily to your liking! Note that you must correctly define docstrings in your C/C++ code: https://stackoverflow.com/a/41245451/4576519