libdispatch in Swift 3, an evolutionary step

Are you following any of the lists.swift.org mailing lists? You can subscribe for emails to follow the open source development of Swift. I’m on the swift-evolution-announce list, and it ends up with a couple emails a day. To me, that’s a reasonable volume. The thing I like about that list is that it’s a broadcast of the approved or rejected changes, no discussion. While it would probably be interesting, I don’t have the bandwidth to be reading through in-depth discussions about how Swift should evolve. Simply catching the end result of the discussion and decision is good enough for me now. When the email arrives, I usually just do a quick glance at the subject to see if it’s something I’m interested in, and recently, oh boy, was there one that caught my eye, it’s related to libdispatch in Swift 3.

Modernize libdispatch for Swift 3 naming conventions

Proposal SE-0088 was accepted to modernize libdispatch in Swift 3 naming conventions. libdispatch, aka Grand Central Dispatch is a modern and easy way to add multithreading to your applications. If you want to learn about it, here’s a great tutorial on Ray Wenderlich’s site (the tutorial is in Objective-C).

For whatever reason, I have such a hard time memorizing any of the C APIs that we use when building our apps. For me, most commonly this is libdispatch. I must have written this code hundreds of times:

Old Way

dispatch_async(dispatch_get_main_queue(),{
    // do something UI-ish on the main thread, like dismiss a view controller
})

but for some reason, I’m never confident in being able to write it based on memory. I almost always have to either lean on code completion, or even go look up a different place I wrote it to copy and paste. And this just scratches the surface of Grand Central Dispatch.

Now, this will all change with Swift 3, as there will be a modernized API available for libdispatch in Swift 3. So that old C code I wrote above will be written as:

New Way

let queue = DispatchQueue.main
queue.asynchronously {
    // do something UI-ish on the main thread, like dismiss a view controller
}

That makes me so happy. Hopefully this modernization of libdispatch in Swift 3 gives you a gist of the cool developments that are happening on the Swift mailing lists and you might even go sign up for them yourself. Let me know, what cool things did you discover?

Happy cleaning.