[swift-evolution] Question about async await

[Adam Kemp]

Pierre responded to the rest of your comments, but I wanted to briefly touch on this:

> On Sep 26, 2017, at 11:22 AM, Jean-Daniel via swift-evolution <swift-evolution at swift.org> wrote:
> 
> In C#, the model is far simple as there is not concept of a single dispatch queue that can execute work on any thread. 


I don’t think this is true in general. The purpose of the SynchronizationContext abstraction is that it allows for different kinds of threading models, and I think the GCD model could work as well. It may be true that in a typical C# application using, say, WPF you don’t have that situation. In most C# frameworks you basically have the UI thread’s context and then you have the generic “thread pool” context. But the way that SynchronizationContext works should allow for you to create a GCD-like system. The way it would work is that when you enter a queue then you would push a SynchronizationContext for that queue, and when you exit the queue you would pop it (restore the previous context). The SynchronizationContext for the queue would implement the Post and Send methods to dispatch_async and dispatch_sync, respectively.

Again, it may be true that a typical C# application doesn’t need this, but I don’t think there’s anything blocking a GCD-like implementation on C# using their system. It’s pretty flexible. I believe a similar system could work for Swift.