arger 2.2.1

Create argparser automatically from function signatures

Overview

A lightweight wrapper around argparse to help build CLIs from functions.

Setup

:gear: Installation

Install it directly into an activated virtual environment:

$ pip install arger

:books: Usage

• create a python file called test.py

from arger import Arger


def main(param1: int, param2: str, kw1=None, kw2=False):
    """Example function with types documented in the docstring.

    Args:
        param1: The first parameter.
        param2: The second parameter.
        kw1: this is optional parameter.
        kw2: this is boolean. setting flag sets True.
    """
    print(locals())


arger = Arger(
    main,
    prog="pytest",  # for testing purpose. otherwise not required
)

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

• Here Arger is just a subclass of ArgumentParser. It will not conceal you from using other argparse libraries.

• run this normally with

$ python test.py -h
usage: pytest [-h] [-k KW1] [-w] param1 param2

Example function with types documented in the docstring.

positional arguments:
  param1             The first parameter.
  param2             The second parameter.

optional arguments:
  -h, --help         show this help message and exit
  -k KW1, --kw1 KW1  this is optional parameter. (default: None)
  -w, --kw2          this is boolean. setting flag sets True. (default: False)

$ python test.py 100 param2
{'param1': 100, 'param2': 'param2', 'kw1': None, 'kw2': False}

• Checkout examples folder and documentation to see more of arger in action. It supports any level of sub-commands.

Features

• Uses docstring to parse help comment for arguments. Supports
  • google
  • numpy
  • rst
• Flags will be generated from parameter-name.
  1. e.g. def main(param: ...) -> -p, --param
  2. If needed you could declare it inside docstring like :param arg1: -a --arg this is the document.
• one can use Argument class to pass any values to the parser.add_argument function
• The decorated functions can be composed to form nested sub-commands of any level.
• Most of the Standard types supported. Please see examples for more supported types with examples.
• No external dependency other than stdlib.

NOTE

• *args supported but no **kwargs support yet.
• all optional arguments that start with underscore is not passed to Parser. They are considered private to the function implementation. Some parameter names with special meaning
  • _namespace_ -> to get the output from the ArgumentParser.parse_args()
  • _arger_ -> to get the parser instance

Argparser enhancements

• web-ui : https://github.com/nirizr/argparseweb
• extra actions : https://github.com/kadimisetty/action-hero
• automatic shell completions using argcomplete