arguments 15

Argument parser based on docopt

Argument parser based on docopt

install

pip install arguments

usage

Docopt is used for parsing the docstring (doc), arguments bundles the schema parser and returns a OptionParser like object with normalized attributes

For example

# coding=utf-8
"""
arguments test

Usage:
  tests.py [options] <posarg1> <posarg2>

Options:
  -h --help                     Show this screen.
  -o --option=<option1>         An option.
  --opt2=<option2>              An option [default: hello].
  -p --parameter=<parameter>    Folder to check the git repos out [default: 77].
  -v --verbose                  Folder from where to run the command [default: .].
"""

from arguments import Arguments

def main():
    """
    main
    """
    arg = Arguments()
    print(arg)


if __name__ == "__main__":
    main()

gives

$ python main.py pval1 pval2
<arguments.Arguments object at 0x1022e0eb8>
options :
    opt2 : hello
    option : None
    parameter : 77
    help : False
    verbose : False
positional :
    posarg1 : pval1
    posarg2 : pval2

or

$ python main.py -h
arguments test

Usage:
  tests.py [options] <posarg1> <posarg2>

Options:
  -h --help                     Show this screen.
  -o --option=<option1>         An option.
  --opt2=<option2>              An option [default: hello].
  -p --parameter=<parameter>    Folder to check the git repos out [default: 77].
  -v --verbose                  Folder from where to run the command [default: .].

$

Using schema

Assume you are using docopt with the following usage-pattern:

my_program.py [--count=N] <path> <files>

and you would like to validate that <files> are readable, and that <path> exists, and that --count is either integer from 0 to 5, or None.

this is how you validate it using schema:

>>> from arguments import *

>>> s = Schema({'<files>': [Use(open)],
...             '<path>': os.path.exists,
...             '--count': Or(None, And(Use(int), lambda n: 0 < n < 5))})

>>> args = Arguments(validateschema=s)

>>> args.files
[<open file 'LICENSE-MIT', mode 'r' at 0x...>, <open file 'setup.py', mode 'r' at 0x...>]

>>> args.path
'../'

>>> args.count
3

As you can see, it validated data successfully, opened files and converted '3' to int.