✨ Add docstring automation to get help message to typer objects

[mateusoliveira43]

Hi everyone,

Thanks for this awesome library, hope I can help :)

I hope this PR closes #227 and #336

My idea was to let typer get help messages to commands/arguments automatically from the objects docstrings.

I considered 3 docstrings formats: Numpy, Google and reST (Sphinx) (I believe they are the most common, right?).

I heve written some tests, but they can be improved (I felt that were a lot of duplications), and more can be written (units tests and more test cases, like callbacks).

[mateusoliveira43]

I have updated the tests, to remove a bit of duplication.

But I noticed a problem: if a parameter documentation takes more then one line, only the first line is parsed. I did not had an idea to fix this yet 😬

[github-actions]

📝 Docs preview for commit 768644c at: https://639cea219c18df08fdc8417d--typertiangolo.netlify.app

[adam-moss]

@tiangolo is this something you'd consider adding? It would be exceedingly useful to incorporate this functionality directly into typer 😄

[pritam-dey3]

I am also waiting for this feature. It's a surprise to me that this is not already part of the library

[adam-moss]

I am also waiting for this feature. It's a surprise to me that this is not already part of the library

May be worth looking at https://cyclopts.readthedocs.io/en/latest/ as an alternative, switching isn't too onerous.

[svlandeg]

Hi, thanks for the PR and apologies for the delay in reviewing this!

I'll put this in draft, update with the latest from master, and then I'll review in more detail.

[svlandeg]

Note: pausing this for a bit longer to first review PRs #815 and #964.

From a first quick review though, I think we could consider using https://github.com/rr-/docstring_parser to implement the functionality proposed in this PR. I'll get back to this once the other PRs are done.