WIP: type hints for tab completion

[ChristopherDavisUCI]

This is an attempt to have tab completion for the property setters by using type hints, as in this comment. I've never worked with type hints before, so I don't know if there is any issue with this approach.

@joelostblom and @mattijn could you please take a look and let me know your impressions?

[mattijn]

Hi @ChristopherDavisUCI, seems you've made great progress!

I tried the following in jupyterlab:

import altair as alt

alt.X().axis(None).title(None)

I was only able to tab-complete the first encoding channel option, here axis(), and not for the following chained encoding channel options, here title(). Can you confirm if this also happens on your side?

[joelostblom]

@ChristopherDavisUCI Great! It might take some time for me before looking closer at this, sorry about that.

@mattijn What you describe sounds like it could be related to this issue in jupyterlab jupyterlab/jupyterlab#12570

[ChristopherDavisUCI]

@mattijn @joelostblom Thanks for checking it out! @mattijn yes I can confirm that doesn't work on either Jupyter notebook or Jupyter lab for me. I wasn't careful about specifying the return type of these methods, so maybe that will help.

[mattijn]

Each encoding channel option should return the encoding channel class in which it is defined, isn't it? Is this possible with these generic protocol class objects?

[ChristopherDavisUCI]

Closing in favor of #2770 which addresses the issues raised above.