> On Aug 31, 2017, at 3:31 PM, Marc Schlichte <[email protected]>
> wrote:
>
>
>> Am 01.09.2017 um 00:04 schrieb Nathan Gray via swift-evolution
>> <[email protected]>:
>>
>> 1. Fixing "queue confusion" *must* be part of this proposal. The key bit of
>> "magic" offered by async/await over continuation passing is that you're
>> working in a single scope. A single scope should execute on a single queue
>> unless the programmer explicitly requests otherwise. Queue hopping is a
>> surprising problem in a single scope, and one that there's currently no
>> adequate solution for.
>>
>> Also consider error handling. In this code it's really hard to reason about
>> what queue the catch block will execute on! And what about the defer block?
>>
>> ```
>> startSpinner()
>> defer { stopSpinner() }
>> do {
>> try await doSomeWorkOnSomeQ()
>> try await doSomeMoreWorkOnSomeOtherQ()
>> } catch {
>> // Where am I?
>> }
>> ```
>>
>> Please, please, PLEASE don't force us to litter our business logic with gobs
>> of explicit queue-hopping code!
>>
>
> In my understanding, this is the advantage of using Actors, as calling
> `await` on actor functions is guaranteed to continue on the queue of the
> calling actor.
>
> Only if you call „legacy“ non-actor async functions, you have to take care of
> queue hopping by yourself - as you do today.
It's true that actors would require a solution to the queue confusion problem,
but not every program will want to use actors. My position is that the syntax
of async/await demands a solution with or without actors. If we're ripping open
the walls anyway let's fix the plumbing!
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