Support overriding behavior hint in argument helptext

[brentyi]

cc #159

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.70%. Comparing base (072dd5f) to head (52bb3a2).
Report is 2 commits behind head on main.

Additional details and impacted files

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  Coverage   99.70%   99.70%           
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  Files          24       24           
  Lines        2035     2040    +5     
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+ Hits         2029     2034    +5     
  Misses          6        6           

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[stevapple]

Looks good. I wonder if it's possible to achieve:

• Explicitly passing in None or a special value to omit the behavioral description;
• Using some placeholder for the default value string so that users can keep the description in sync if it includes the default value.

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A cent on implementation of the two feature requests:

• The latter is easy to achieve by substring replacement, although we need to figure out what the ideal placeholder is.
• The former is a bit tricky because Python doesn't have something like JavaScript's undefined, so we might need a dict or a new placeholder type for such case... I think a judgement for '' should work.

[brentyi]

Great!

Using some placeholder for the default value string so that users can keep the description in sync if it includes the default value.

Do you have concrete/example use cases for this? The maintenance burden here is small so I could entertain this if it's useful enough, but I'm not a fan of the substring replacement from an API perspective. One other option is help_behavior_hint: str | Callable[[str], str] | None, where the lambda function is internally called with the default string representation.

[stevapple]

One other option is help_behavior_hint: str | Callable[[str], str] | None, where the lambda function is internally called with the default string representation.

I also like this idea! It looks very neat and familiar.

Do you have concrete/example use cases for this?

This would help if the user is passing in a default value with a dict, so that the initial Args may not know what the default value is. It’s also risking forgetting to update the hint text after the default value changed.