In Part 1 I wrote what this mini-series would be all about. Given the default array filtering is a performance bottleneck for my fictional app, I’m going to explore if I can write code that performs better in my specific use case. In this part, I’m going to rewrite my initial filtering function and use the new async/await Swift concurrency syntax. An async filter function Since TaskGroup still has a performance issue in the current version of Swift, I’ll use a simplified code that uses only top tasks (e. …

This will be yet another exploratory series on my blog — this time around, I want to write a little about optimizing performance in Swift code. This is, of course, an endless topic so what I’m going to do is, similarly to previous posts, focus on a problem and then track my way through working on it. Also, since this might turn into a somewhat longer read, I thought I’d split it into several short parts; so if you are in fact interested to read through you don’t have to put in all the time at once. …

For my talk at iOS Conf SG 2022 I wanted to showcase some Swift concurrency use-cases that don’t fall into the common scenarios. Revisiting the slides some weeks later, I think it’d be fun to cover my TaskGroup example in more detail. In this post I’ll show how to use TaskGroup to design a complete (but fictional) user login-sequence. What is TaskGroup good for? Most examples floating around show using a TaskGroup to add a number of identical tasks to a group and execute them concurrently. …

This post is not my usual format but there is a moral at the end, so hang around if you have a little time to waste. The setup I’m working on a longer blog post about the process of optimizing some concurrency Swift code. At a point I used John Sundell’s CollectionConcurrencyKit to compare the performance of different approaches. After I had my numbers, I peaked into his code to double check what exactly am I measuring. …

For the ones who missed it last November, I’ve been playing with a Swift IDE prototype which allows you to easily develop Swift scripts for the mac. I shared a video showcase demoing how the tight integration of the IDE with the toolchain allows you to write scripts, capture inputs and outputs, and all that in a neat SwiftUI interface: More than anything else I worked on this to explore and demonstrate how easily I can build powerful Swift tools. …

Edit: The post previsouly said yielding accessors were available only in nightly toolchains, but _read and _modify are also available in release Swift builds; they’re just _ prefixed to signify they are work-in-progress. It seems that Swift 5.6 is shaping up to a great iteration of the language and will bring a round improvements to performance-critical Swift code. I was reading through a pitch by Joe Groff on some improvements to ARC and ownership the other day when I noticed that he mentions that accessor coroutines are available in Swift trunk. …

In Swift Async Sequence extensions (part 1) I covered simple ways to create an async sequence using a custom factory method and binding a sequence to a UI control via a custom assign method. This covered the “beginning” and “end” of the data stream (so to say) but what about processing or converting the data along the way? If you draw a parallel to Combine code — how would you build custom “operators” for your async sequence? …

I’ve been trying out various ways to extend and build upon the currently available Concurrency APIs introduced in Swift 5.5 I believe the Concurrency APIs are intentionally somewhat minimal so that developers would intentionally fall back on Combine for complex tasks. Maybe I’m right or wrong but I can see how a lot of people will want to extend the Concurrency APIs to suit better their current tasks. In this post I’ll code a couple of extensions that show how to easily build your own concurrent power-ups. …

In this post I describe the technical setup of a small language experiment I developed to aid myself working on custom Xcode instruments. The need for a more flexible coding inside Xcode Last month, I prototyped a Swift IDE and became very interested in enhancing the experience of building with Swift. (Since Apple doesn’t hire remotely, I wonder what other companies are working in that area?) A little later, I came back to updating my custom Xcode Instrument called Timelane to support debugging new code based on the new Swift modern concurrency APIs: …

I’m incredibly happy to share that today the new raywenderlich.com book “Modern Concurrency in Swift”, that I’ve been working on, is available at swiftconcurrencybook.com! Together with editors Sandra Grauschopf, Felipe Laso-Marsetti, Richard Turton, and Shai Mishali, we’ve been working very hard to get a book out as soon as possible on the newly released in 2021 Swift Concurrency: The book is written in the classic raywenderlich.com style that mixes key pieces of theory with step-by-step instructions, guiding the readers through working on practical, real-life projects. …