argser

argser

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Arguments parsing without boilerplate.

Features:

• arguments and type hints in IDE
• easy nested sub-commands
• sane defaults for arguments' params (ie if default of arg is 3 then type should be int, or when annotation/type/default is bool then generate 2 arguments: for true value --arg and for false --no-arg, ...)
• 𝕡𝕣𝕖𝕥𝕥𝕪 𝕡𝕣𝕚𝕟𝕥𝕚𝕟𝕘
• support for argparse actions
• common options/arguments reusability
• auto shortcuts generation: --verbose -> -v, --foo_bar -> --fb
• auto completion in shell (tnx to argcomplete)

Installation

pip install argser
pip install argser[tabulate]  # for fancy tables support
pip install argser[argcomplete]  # for shell auto completion
pip install argser[all]

Notes for examples

If second parameter of parse_args is string (as in almost all examples) then it will be parsed, otherwise arguments to parse will be taken from command line.

Simple example

from argser import parse_args

class Args:
    a = 'a'
    foo = 1
    bar: bool
    bar_baz = 42, "bar_baz help"

args = parse_args(Args, show=True)

argparse alternative

from argparse import ArgumentParser

parser = ArgumentParser()
parser.add_argument('-a', type=str, default='a', help="str, default: 'a'")
parser.add_argument('--foo', '-f', dest='foo', type=int, default=1, help="int, default: 1")
parser.add_argument('--bar', '-b', dest='bar', action='store_true', help="bool, default: None")
parser.add_argument('--no-bar', '--no-b', dest='bar', action='store_false')
parser.set_defaults(bar=None)
parser.add_argument('--bar-baz', dest='bar_baz', default=42, help="int, default: 42. bar_baz help")

args = parser.parse_args()
print(args)

❯ python playground.py -a "aaa bbb" -f 100500 --no-b
>>> Args(bar=False, a='aaa bbb', foo=100500, bar_baz=42)

❯ python playground.py -h
usage: playground.py [-h] [--bar] [--no-bar] [-a A] [--foo F] [--bar-baz B]

optional arguments:
    -h, --help           show this help message and exit
    --bar, -b            bool, default: None
    --no-bar, --no-b
    -a A                 str, default: 'a'
    --foo F, -f F        int, default: 1
    --bar-baz B, --bb B  int, default: 42. bar_baz help

Get arguments from function

import argser

def foo(a, b: int, c=1.2):
    return [a, b, c]

assert argser.call(foo, '1 2 -c 3.4') == ['1', 2, 3.4]

Sub-commands

from argser import parse_args, sub_command

class Args:
    a: bool
    b = []
    c = 5

    class SubArgs:
        d = 1
        e = '2'
    sub = sub_command(SubArgs, help='help message for sub-command')

args = parse_args(Args, '-a -b a b -c 10', parser_help='help message for root parser')
assert args.a is True
assert args.b == ['a', 'b']
assert args.c == 10
assert args.sub is None

args = parse_args(Args, '--no-a -c 10 sub -d 5 -e "foo bar"')
assert args.a is False
assert args.sub.d == 5
assert args.sub.e == 'foo bar'

❯ python playground.py -h
usage: playground.py [-h] [-a] [--no-a] [-b [B [B ...]]] [-c C] {sub} ...

positional arguments:
    {sub}

optional arguments:
    -h, --help      show this help message and exit
    -a              bool, default: None
    --no-a
    -b [B [B ...]]  List[str], default: []
    -c C            int, default: 5

❯ python playground.py sub1 -h
usage: playground.py sub [-h] [-d D] [-e E]

help message for sub-command

optional arguments:
    -h, --help  show this help message and exit
    -d D        int, default: 1
    -e E        str, default: '2'

Can be deep nested:

from argser import parse_args, sub_command

class Args:
    a = 1
    class Sub1:
        b = 1
        class Sub2:
            c = 1
            class Sub3:
                d = 1
            sub3 = sub_command(Sub3)
        sub2 = sub_command(Sub2)
    sub1 = sub_command(Sub1)

args = parse_args(Args, '-a 1 sub1 -b 2 sub2 -c 3 sub3 -d 4')

Sub-commands from functions

import argser
subs = argser.SubCommands()

@subs.add
def foo():
    return 'foo'

@subs.add(description="foo bar")  # with additional arguments for sub-parser
def bar(a, b=1):
    return [a, b]

assert subs.parse('foo') == 'foo'
assert subs.parse('bar 1 -b 2') == ['1', 2]