argser 0.0.1

argparse without boilerplate

argser

argparse without boilerplate

simple example

from argser import ArgsParser

class Args(ArgsParser):
    a = 'a'
    foo = 1
    bar = True


args = Args().parse()
print(repr(args.a), args.foo, args.bar)

python playground.py -a "aaa bbb" -f 100500 --no-b
>> 'aaa bbb' 100500 False

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

optional arguments:
  -h, --help            show this help message and exit
  -a [A]                str, default: 'a'.
  --foo [FOO], -f [FOO]
                        int, default: 1.
  --no-bar, --no-b      bool, default: True.

complex example

from argser import ArgsParser, Command, Argument, PosArgument

class Args(ArgsParser):
    a: bool  # default None, will generate 2 args - --a and --no-a
    b = []  # nargs==*, List[str]
    c = 5
    d = Argument(default=3, aliases=('dd', 'ddd'), help="foo", keep_default_help=False)  # for complex arguments
    # arguments after `Commands` will belong to separate subparser named after command
    another = Command()
    e = ['str']  # nargs==+
    f: int = None
    g: str = PosArgument()  # positional argument

    class SubCommand(ArgsParser):
        k = 1
        l = 2

    another2 = SubCommand()


args = Args().parse().print()

❯ python playground.py -h

usage: playground.py [-h] [-a] [--no-a] [-b [B [B ...]]] [-c [C]] [-d D]
                     {another2,another} ...

positional arguments:
  {another2,another}
    another

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.
  -d D, --dd D, --ddd D
                        foo

❯ python playground.py another -h

usage: playground.py another [-h] [-e [E]] [-f [F]] g

positional arguments:
  g             str, default: None.

optional arguments:
  -h, --help    show this help message and exit
  -e E [E ...]  List[str], default: ['str'].
  -f [F]        int, default: None.

❯ python playground.py another2 -h

usage: playground.py another2 [-h] [-k [K]] [-l [L]]

optional arguments:
  -h, --help  show this help message and exit
  -k [K]      int, default: 1.
  -l [L]      int, default: 2.

more

for more usage examples check out tests.py file

notes

1. annotations are not static fields

class Args(ArgsParse):
    com = Command()
    a: str

assert hasattr(Args, 'a') is False

Annotation "fields" don't appear in cls.__dict__ at all. That's why we can't track their order in class definition which means that we can't use them with Command. You need to explicitly specify default value to convert simple annotation into field with annotation.

If you don't have sub-commands and don't have default values for arguments then it's okay to use them.

class Args(ArgsParse):
    com = Command()
    a: str = None  # now `a` is part of `com` subparser

2. explicitly specify type for arguments defined with Argument class to help your IDE

class Args(ArgsParse):
    a: int = Argument(default=3)

argser will know about type of a without annotation (it can be determined by default value), but if you want your IDE to know that args.a is int and not Argument then you need explicit annotation.