[WIP] tapify with subparsers

[kddubey]

Fix #101

Not ready for a full review yet, but I'd appreciate feedback on the overall approach

I'll do all of the # TODO: s and add tests soon

I'll also study fire.Fire's interface and behavior a bit more to understand what ppl want out of this type of feature

[kddubey]

Demo

# demo_subparsers.py
from typing import List, Optional

from tap import tapify_with_subparsers


class Class:
    def __init__(self, arg_int: int, arg_bool: bool = True, arg_list: Optional[List[int]] = None):
        """
        :param arg_int: some integer
        :param arg_list: some list of integers
        """
        self.arg_int = arg_int
        self.arg_bool = arg_bool
        self.arg_list = arg_list

    def my_method(self, x: int) -> int:
        """Summary of my method

        :param x: an integer
        :return: another integer
        """
        return self.arg_int + x

    def my_other_method(self) -> Optional[List[int]]:
        """Summary of my other method

        :return: hmmm
        """
        return self.arg_list if self.arg_bool else None

    def __repr__(self) -> str:
        return f"{self.arg_int=} {self.arg_bool=} {self.arg_list=}"


if __name__ == "__main__":
    print(tapify_with_subparsers(Class))

Running—

python demo_subparsers.py -h

—outputs:

usage: demo_subparsers.py --arg_int ARG_INT [--arg_bool] [--arg_list [ARG_LIST ...]] [-h] {my_method,my_other_method} ...

positional arguments:
  {my_method,my_other_method}
                        sub-command help
    my_method           my_method help
    my_other_method     my_other_method help

options:
  --arg_int ARG_INT     (int, required) some integer
  --arg_bool            (bool, default=True)
  --arg_list [ARG_LIST ...]
                        (Optional[List[int]], default=None) some list of integers
  -h, --help            show this help message and exit

Running—

python demo_subparsers.py my_method -h

—outputs:

usage: demo_subparsers.py my_method --x X [-h]

my_method description

options:
  --x X       (int, required)
  -h, --help  show this help message and exit

Running—

python demo_subparsers.py --arg_int 2 my_method --x 110

—outputs:

112

Running—

python demo_subparsers.py --arg_list 1 2 3 --arg_int 2 my_other_method

—outputs:

[1, 2, 3]

[kddubey]

The name-collision issue is weird. Play w/ this argparse script:

# demo_names.py
import argparse

parser = argparse.ArgumentParser()
parser.add_argument("--verbose", default=0, type=int)

subparsers = parser.add_subparsers(dest="parser_name")

parser_lan = subparsers.add_parser("car")
parser_lan.add_argument("--boo")
parser_lan.add_argument("--verbose")  # collides w/ name in the main parser

parser_serial = subparsers.add_parser("bus")
parser_serial.add_argument("--fun")

print(parser.parse_args())

For example, running—

python demo_names.py --verbose 1 car --boo booval

outputs:

Namespace(verbose=None, parser_name='car', boo='booval')

Seems unexpected.

Not sure how to handle it: be consistent w/ argparse behavior, or attempt to fix it by separating the namespaces for the main parser and subparsers as in, e.g., here. Or (what I think I'll go with for now) raise an error

[martinjm97]

TODO: think about how to set

I think that the docstring for that method should work well

[martinjm97]

Hi @kddubey,

This PR looks awesome so far. Thank you!!

Or (what I think I'll go with for now) raise an error

I'm a fan of the approach where Tap raises an error for name collisions and then adds a flag that applies a solution similar to the one in the stackoverflow that you linked. I think that second part can be a separate issue and implementation. For this PR, I think that raising an error is good.

Kyle and I will discuss more soon.

Thanks again,
Jesse

[martinjm97]

Maybe add a decorator to mark methods as subparsers then this can all be integrated into the existing tapify implementation.

--JK

[kddubey]

Neat. That sounds like a better interface