Docopt - Command-line interface description language

When we want a user-friendly command-line interface

What we want are:

• useful help and usage messages
• easy to parse the arguments

Docopt helps you:

• define interface for your command-line app
• automatically generate parser for it

Seems other libs in python can handle this also, like: argparse, optparse, getopt, click.

But after I used all of those libs, I find docopt is the easiest way to handle this, and what your see is what your get.

Demo(naval_fate.py)

"""Naval Fate.

Usage:
  naval_fate.py ship new <name>...
  naval_fate.py ship <name> move <x> <y> [--speed=<kn>]
  naval_fate.py ship shoot <x> <y>
  naval_fate.py mine (set|remove) <x> <y> [--moored|--drifting]
  naval_fate.py -h | --help
  naval_fate.py --version

Options:
  -h --help     Show this screen.
  --version     Show version.
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine.

"""
from docopt import docopt


if __name__ == '__main__':
    arguments = docopt(__doc__, version='Naval Fate 2.0')
    print(arguments)

When you want to get help and usage messages

python naval_fate.py –help

Naval Fate.
	
Usage:
  naval_fate.py ship new <name>...
  naval_fate.py ship <name> move <x> <y> [--speed=<kn>]
  naval_fate.py ship shoot <x> <y>
  naval_fate.py mine (set|remove) <x> <y> [--moored|--drifting]
  naval_fate.py -h | --help
  naval_fate.py --version

Options:
  -h --help     Show this screen.
  --version     Show version.
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine.

And when we type: python naval_fate.py ship new ‘Going Merry’

The parsed arguments are:

{'--drifting': False,
 '--help': False,
 '--moored': False,
 '--speed': '10',
 '--version': False,
 '<name>': ['Going Merry'],
 '<x>': None,
 '<y>': None,
 'mine': False,
 'move': False,
 'new': True,
 'remove': False,
 'set': False,
 'ship': True,
 'shoot': False}

Write less code than others, and get all what we want, this is Docopt

Visit Homepage to get all the documents.

Read Github to know the amazing code.

Try Demo Source Code in your terminal.