Construct CLI from a signature

parsing_signature.py

import argparse
import signature

def make_cli(func: callable):
    parser = argparse.ArgumentParser()
    sig = inspect.signature(func)
    empty = inspect._empty

    for param in sig.parameters.values():
        annot = param.annotation
        options = {}
        
        if annot is empty:
            ptype = str
        elif isinstance(annot, tuple):
            ptype, help_msg = annot
            if help_msg is not empty:
                options['help'] = help_msg
        else:
            ptype = annot
        options['type'] = ptype
        if param.default is empty:
            options['required'] = True
        else:
            options['default'] = param.default
            if annot is empty:
                options['type'] = type(options['default'])

        name = param.name.replace('_', '-')
        parser.add_argument(f'--{name}', **options)

    func(**vars(parser.parse_args()))