SE-0300: Continuations for interfacing async tasks with synchronous code

[benrimmington]

@Ben_Cohen

Why is it better to use Result to cut back the API surface from 2 methods to one? Why is using Result with Never better than a throwing and non-throwing variant?

By having fewer API variants, I find them easier to learn and use. I was also trying to limit top-level Unsafe* and withUnsafe* APIs, for better auto-completion of the existing pointer APIs.

@Ben_Cohen

I’d very much discourage people pushing Result as an alternative to throwing …

I now understand your concern, but that wasn't my intention. My earlier example uses try result.get() immediately.

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@benrimmington

Are the with*Continuation methods misnamed? The continuation is allowed to escape the given closure, unlike other with* methods in the standard library.

Could this be improved by adding a static suspend method to each continuation type?

try await UnsafeThrowingContinuation.suspend { continuation in
  /* ... */
  continuation.resume(returning: value)
}