dsargparse is a wrapper of argparse library which prepares helps and descriptions from docstrings. It also sets up functions to be run for each sub command, and provides a helper function which parses args and run a selected command.
Using this library, you don't need to write same texts in docstrings, help, and description.
Use pip to install from PyPi.
$ pip install -U dsargparse
Suppose to make a following trivial greeting command consists of two subcommands supplied as functions shown below.
"""Sample command of dsargparse package.
This text will be used as description of this command.
"""
def greeting(title, name): # pylint: disable=unused-argument
"""Print a greeting message.
This command print "Good morning, <title> <name>.".
Args:
title: title of the person.
name: name of the person.
"""
print("Good morning, {title} {name}.".format(**locals()))
return 0
def goodbye(name): # pylint: disable=unused-argument
"""Print a goodbye message.
This command print "Goodbye, <name>.".
Args:
name: name of the person say goodbye to.
"""
print("Goodbye, {name}".format(**locals()))
return 0The dsargparse reduces codes you need from the before
# Before dsargparse
import sys
import textwrap
import argparse
def main():
""" The main function.
"""
parser = argparse.ArgumentParser(
description=textwrap.dedent("""\
Sample command of argparse package.
This text will be used as description of this command.
"""))
subparsers = parser.add_subparsers()
greeting_cmd = subparsers.add_parser(
"greeting",
help="Print a greeting message.",
description=textwrap.dedent("""\
Print a greeting message.
This command print "Good morning, <title> <name>".
"""))
greeting_cmd.add_argument(
"title", help="title of the person say greetings to")
greeting_cmd.add_argument(
"name", help="name of the person say greetings to.")
greeting_cmd.set_defaults(cmd=greeting)
goodbye_cmd = subparsers.add_parser(
"goodbye",
help="Print a goodbye message.",
description=textwrap.dedent("""\
Print a goodbye message.
This command print "Goodbye, <name>".
"""))
goodbye_cmd.add_argument(
"name", help="name of the person say goodbye to.")
goodbye_cmd.set_defaults(cmd=goodbye)
args = parser.parse_args()
return args.cmd(**args)
if __name__ == "__main__":
sys.exit(main())to the after
# After dsargparse
import sys
import dsargparse
def main():
""" The main function.
"""
parser = dsargparse.ArgumentParser(main=main)
subparsers = parser.add_subparsers()
greeting_cmd = subparsers.add_parser(greeting)
greeting_cmd.add_argument("title")
greeting_cmd.add_argument("name")
goodbye_cmd = subparsers.add_parser(goodbye)
goodbye_cmd.add_argument("name")
return parser.parse_and_run()
if __name__ == "__main__":
sys.exit(main())dsargparse is a simple wrapper of the original argparse. To use it, install
this package and just adding ds to your import command i.e. from
import argparse to import dsargparse. In addition to all API argparse has,
dsargparse updates three functions; constructor of ArgumentParser object,
ArgumentParser.add_argument, and add_parser method of the action class made
by ArgumentParser.add_subparsers(), and give one new method
ArgumentParser.parse_and_run.
In addition to the keyword arguments argparse.ArgumentParser takes,
this constructor has keyword argument main which takes the main function.
If you give the main function, you don't need to set description, and
formatter_class also will be set automatically.
This method adds a new argument to the current parser. The function is
same as argparse.ArgumentParser.add_argument. But, this method
tries to determine help messages for the adding argument from some
docstrings.
If the new arguments belong to some subcommand, the docstring
of a function implements behavior of the subcommand has Args: section,
and defines same name variable, this function sets such
definition to the help message.
After constructing subparsers by subparsers = parser.add_subparsers(),
you may call subparsers.add_parser to add a new subcommand.
The add_parser has a new positional argument func which takes a function
to be called in order to run the subcommand. The func will be used
to determine the name, help, and description of this subcommand. The
function func will also be set as a default value of cmd attribute.
The add_parser also has as same keyword arguments as add_parser of argparse
library.
This method parses arguments and run the selected command. It returns a value
which the selected command returns. This function takes as same arguments as
ArgumentParser.parse_args.
See more detail of original argparse.
This software is released under the MIT License, see LICENSE.