docopt http://docopt.org/ 

bill israel @epochblue 

a typical example 

$ python boo-argparse.py -h usage: boo-argparse.py [-h] [--sum] N [N ...] Process some integers. positional arguments: N an integer for the accumulator optional arguments: -h, --help show this help message and exit --sum sum the integers (default: find the max) 

# boo-argparse.py import argparse parser = argparse.ArgumentParser(description='Process some integers.') parser.add_argument('integers', metavar='N', type=int, nargs='+', help='an integer for the accumulator') parser.add_argument('--sum', dest='accumulate', action='store_const', const=sum, default=max, help='sum the integers (default: find the max)') args = parser.parse_args() print args.accumulate(args.integers) 

argument parsing usage ARGPARSE 

usage statements 

Naval Fate. Usage: naval_fate ship new ... naval_fate ship move [--speed=] naval_fate ship shoot naval_fate mine (set|remove) [--moored|--drifting] naval_fate -h | --help naval_fate --version Options: -h --help Show this screen. --version Show version. --speed= Speed in knots [default: 10]. --moored Moored (anchored) mine. --drifting Drifting mine. 

usage argument parsing DOCOPT 

$ python yay-docopt.py -h usage: yay-docopt.py [--sum] N [N ...] Process some integers. Arguments: N an integer for the accumulator Options: -h, --help show this help message and exit --version show version information --sum sum the integers 

# yay-docopt.py import argparse parser = argparse.ArgumentParser(description='Process some integers.') parser.add_argument('integers', metavar='N', type=int, nargs='+', help='an integer for the accumulator') parser.add_argument('--sum', dest='accumulate', action='store_const', const=sum, default=max, help='sum the integers (default: find the max)') args = parser.parse_args() print args.accumulate(args.integers) 

example: boom 

requirements simple key/value store four commands no command = get 

boom - a simple CLI key-value store Usage: boom boom get boom add [-f|--force] [] boom delete [-f|--force] boom find Commands: add Adds with value get Displays the value of delete Deletes and its value find Find keys matching Options: -h, --help Print this message --version Print version information -f, --force Don't confirm the action 

BOOM.PY """ boom - a simple CLI key-value store Usage: boom boom get boom add [-f|--force] [] boom delete [-f|--force] boom find Commands: add Adds with value get Displays the value of delete Deletes and its value find Find keys matching Options: -h, --help Print this message --version Print version information -f, --force Don't confirm the action """ 

BOOM.PY """ boom - a simple CLI key-value store Usage: boom boom get boom add [-f|--force] [] boom delete [-f|--force] boom find Commands: add Adds with value get Displays the value of delete Deletes and its value find Find keys matching Options: -h, --help Print this message --version Print version information -f, --force Don't confirm the action """ from docopt import docopt 

""" boom - a simple CLI key-value store Usage: boom boom get boom add [-f|--force] [] boom delete [-f|--force] boom find Commands: add Adds with value get Displays the value of delete Deletes and its value find Find keys matching Options: -h, --help Print this message --version Print version information -f, --force Don't confirm the action """ from docopt import docopt if __name__ == '__main__': arguments = docopt(__doc__, version='boom.py 1.0') print(arguments) BOOM.PY 

python boom.py add -f abc Usage: boom boom get boom add [-f|--force] [] boom delete [-f|--force] boom find {'--force': True, '': None, '': 'abc', '': None, 'add': True, 'delete': False, 'find': False, 'get': False} $> 

python boom.py add abc xyz Usage: boom boom get boom add [-f|--force] [] boom delete [-f|--force] boom find {'--force': False, '': 'xyz', '': 'abc', '': None, 'add': True, 'delete': False, 'find': False, 'get': False} $> 

python boom.py get abc xyz Usage: boom boom get boom add [-f|--force] [] boom delete [-f|--force] boom find $> 

BOOM.PY """ boom - a simple CLI key-value store Usage: boom boom get boom add [-f|--force] [] boom delete [-f|--force] boom find Commands: add Adds with value get Displays the value of delete Deletes and its value find Find keys matching Options: -h, --help Print this message --version Print version information -f, --force Don't confirm the action """ from docopt import docopt if __name__ == '__main__': arguments = docopt(__doc__, version='boom.py 1.0') print(arguments) 

¯\_(ツ)_/¯ 

benefits 

small dependency easy to read/write doubles as documentation follows a convention 

(fine print) 

what can’t it do? no validation/type safety no secondary parsing spotty error messages 

but it’s still better than argparse 

docopt @epochblue thank you.