Define Resource Subtyping

[esoterra]

If WASI is going to use Resource Subtyping, it should probably be rendered here first so that implementations can conform to an official definition/specification of how they work.

[lukewagner]

Yes, you're right. Technically, all existing resource/handle support in wit is ahead of the spec here; the plan was to add resources+handles right after the value types, but then async/streaming got priority boosted. This presentation covers a lot of the original design thinking about subtyping (particularly around dynamic casts), but it's pre-canonical-ABI and needs to be updated. But yes, we need to get some basic skeleton sketches of resources/handles/subtyping here ASAP.

[rektide]

but then async/streaming got priority boosted.

where can we look to find discussion or work on this matter? thanks luke.

[Liamolucko]

where can we look to find discussion or work on this matter?

The proposal for async is here: https://docs.google.com/presentation/d/1MNVOZ8hdofO3tI0szg_i-Yoy0N2QPU2C--LzVuoGSlE

[lukewagner]

Also, the third-and-final presentation of these slides will be in the next WASI meeting.