Converts functions into simple commands.

f2cmd.py

'''
Converts functions into simple commands.
Turns function arguments into command line arguments, and docstrings into helpstrings.
Essentially an argparse shortcutter.

e.g.

@f2cmd.cmd(arg1={"type": int})
def my_main_function(arg1, arg2):
    pass

if __name__ == "__main__":
    my_main_function.run()

'''
import argparse
import functools
import inspect

def cmd(_overrides=None, **kwargs):
    overrides = _overrides or {}
    overrides.update(kwargs)

    class Command(object):
        '''
        Command is intended to be used as a decorator or wrapper for the
        main function.
        '''
        def __init__(self, f):
            self.f = f
            code = f.func_code
            defaults = f.func_defaults
            nargs = code.co_argcount
            argnames = code.co_varnames[:nargs]
            if defaults:
                defaults = zip(argnames[-len(defaults):], defaults)
                argnames = argnames[:-len(defaults)]
            self.parser = argparse.ArgumentParser(f.__doc__)
            for name in argnames:
                parser.add_argument(
                    name, **overrides.get(name, {}))
            for name, default in defaults:
                parser.add_argument(
                    name, default=default, **overrides.get(name, {}))

        def run(self):
            return self.f(**self.parser.parse_args().__dict__)

        def __call__(self, *args, **kwargs):
            return self.f(*args, **kwargs)

    return Command