help doesnt show the default for optionals

[euri10]

from dataclasses import dataclass
import cappa
from typing_extensions import Annotated


@dataclass
class Example:
    single_option: Annotated[int, cappa.Arg(short=True, help="A number")] = 42


args: Example = cappa.parse(Example, backend=cappa.backend)
print(args)

will produce this help:

❯ python ex.py --help
Usage: example [-s SINGLE_OPTION] [-h] [--completion COMPLETION]
                                                                                                                         
  Options                                                                                                                
    [-s SINGLE_OPTION]         A number                                                           
                                                                                                                         
  Help                                                                                                                   
    [-h, --help]               Show this message and exit.                                                      
    [--completion COMPLETION]  Use `--completion generate` to print shell-specific completion source. Valid options:
                               generate, complete.

however I find it would be definitely clearer from a user's perspective to have somehting like:

❯ python ex.py --help
Usage: example [-s SINGLE_OPTION] [-h] [--completion COMPLETION]
                                                                                                                         
  Options                                                                                                                
    [-s SINGLE_OPTION]         Default: 42 . A number                                                           
                                                                                                                         
  Help                                                                                                                   
    [-h, --help]               Show this message and exit.                                                      
    [--completion COMPLETION]  Use `--completion generate` to print shell-specific completion source. Valid options:
                               generate, complete.

wdyt ?

[DanCardin]

Yea, I think I perhaps had this originally then decided formatting-wise, it was hard to predict the formatting/casing of the users' help text such that it always looks consistent.

I could certainly add a default_help=True (or something like that) option to Arg, or I could supply default as a help text formatter like help="Default: {default}. A number", allowing the user to essentially decide their own default formatting. I assume the goal here is mostly to avoid duplicating the actual value, and less about saving the help text characters?

[euri10]

I like both options except in both cases I'd have to add it for each and every Arg.

Imho showing the default should be the default ( ) and you could have a Arg option not to show it if you dont like the formatting, kind of the opposite, but honestly just a way to show it would be awesome

[DanCardin]

well once it's a per-arg option at all, there could be a cappa.parse/invoke-level global option also.

Perhaps... cappa.invoke(help_options=HelpOptions(arg_format="{help} (Default: {default})")) or something to that effect. I very much like the idea of format strings for helping to control this, but because of the spaces, i doesn't lend itself ideally to help being potentially an empty string.

[DanCardin]

#126, lmk how you think that looks, before i commit to merging 😛. Although, i also did update the default to including...the default value, so for practical purposes, the details i guess might not matter to you :P