Argument Clinic

Ah. I'd like to have an argument, please.

The standard way of writing a command line tool in Python is rather repetitive. You construct an ArgumentParser object with a doc string add documented parameters with their type, call parse on it and then call your main(...) with exactly the same parameters and if you are a good citizen, you document the call stuff again.

def main(input_file : str, *, scale : float = 125, fps : int = 30):
    """Create a movie based that has droste aspects."""
    pass

if __name__ == '__main__':
    parser = argparse.ArgumentParser('Create a movie based that has droste aspects.')
    parser.add_argument('input_file', type=str)
    parser.add_argument('--scale', type=float, default=125)
    parser.add_argument('--fps', type=float, default=30)

    args = parser.parse_args()

    main(args.input, scale=args.scale, fps=args.fps)

With argument-clinic you can do the same with just:

@argument.entrypoint
def main(input_file : str, *, scale : float = 125, fps : int = 30):
    """Create a movie based that has droste aspects."""
    pass

if __name__ == '__main__':
    main()

Installation

pip install argument-clinic

More details

As shown above, the basic usage is to use the @argument.entrypoint for your main and have all command line arguments to your script be arguments of your main(..) entry point. When you call main the values for each argument will be supplied automatically.

Separate positional arguments and keyword arguments in your main with a * (which is good practice anyway). Anything after the star becomes a flag that requires a value.

The doc string of your main will automatically become the help for your script. If you document the parameters to your main in your doc string, these comments will be added to the right parameters (any type specification will be ignored though)

The best thing: it doesn't cost you 5 pounds for 5 more minutes.