[Pitch #2] Structured Concurrency

[Lantua]

Jumped from the quoted thread.

@Douglas_Gregor

@Lantua

Should we also include TaskAPIs (cancellation, task local) in UnsafeContinuation ?

extension UnsafeContinuation {

var currentTask: Task.Handle { ... }
}

I don't think we want to provide a separate API to access the task handle from here; if we allow you to get a task handle for the current task, you can capture that in the closure instead. If we don't allow you to get a task handle for the current task, we shouldn't have this API either.

As is, Task APIs, e.g. Task.isCancelled requires the caller to be an async function, but Continuation is used only on non-async function.

AFAICT, to allow the Task -related usage in continuation block, we need to either

• Make Task API works on any non-async function, or
• Provide Task.Handle to the continuation block,
• Copy all Task functionality onto UnsafeContinuation , turn them into non-async version (since we now know which Task it is referring to).