The year is 2025. You’re writing tests for networking code in your Swift app. You could hit the live API, but then your tests are slow, flaky, and fail whenever that third-party service has a bad day. You could stub URLSession, but then you’re maintaining two implementations of your networking layer...

A few years ago, Twitter user @38mo1, a chemistry teacher from Japan, posted a Halloween × Boolean logic meme that I liked enough to save to ~/Downloads. And ever since, I’ve had a yearly reminder every October 1st to open the image and get a seasonal chuckle 🎃 More recently, I wanted to teach my ki...

Ahh, @isolated(any). It’s an attribute of contradictions. You might see it a lot, but it’s ok to ignore it. You don’t need to use it, but I think it should be used more. It must always take an argument, but that argument cannot vary. Confusing? Definitely. But we’ll get to it all. To understand why ...

You know what’s wrong with people? They’re too sure of themselves. Better to be wrong and own it than be right with caveats. Hard to build a personal brand out of nuance these days. People are attracted to confidence — however misplaced. But can you blame them? (People, that is) Working in software,...

Language Server Protocol (LSP) revolutionized how programming languages integrate with developer tools. Model Context Protocol (MCP) aims to do the same for a new generation of AI tools. But before we lay our scene of two protocols (both alike in dignity), let’s take a moment to motivate the problem...

“Only Apple can do this” Variously attributed to Tim Cook Apple introduced Apple Intelligence at WWDC 2024. After waiting almost a year for Apple to, in Craig Federighi’s words, “get it right”, its promise of “AI for the rest of us” feels just as distant as ever. Can we take a moment to appreciate t...

.env files. If you’ve worked on a web application, you’ve probably seen one. While they certainly get the job done, .env files have shortcomings that can create friction in development workflows. We’ve touched on .env files in past articles about xcconfig files and secret management on iOS. But this...

Chris Lattner often describes LLVM as a process of lowering. You start at the highest level of abstraction, source code written in a programming language like Swift or Objective-C. That code is parsed into an abstract syntax tree, (AST), which is progressively transformed into lower-level, intermedi...

Like everything else in 2020, this year’s WWDC had to be a little different if it was going to happen at all. When Apple first announced that the conference would be fully remote, nobody knew what that would look like, exactly. What parts of the dubdub experience would be kept in this new format? Wh...

In October 2018, Apple announced on the Swift.org forums that it was starting work to adopt the Language Server Protocol (LSP) for Swift and C languages. At Apple we are making it a priority to support high-quality tooling for all Swift developers, including those working on non-Apple platforms. We ...