Concrete and "Soft" Types in Swift

Mon, 01 Apr 2024 00:00:00 +0000

In our last article, we learned about how the generics system is deeply integrated into Swift at practically every level. This can give us magical features that help like Type Inference which makes our code easier to read and right, but it can also lead frustrating and confusing compile-time errors. Furthermore, most modern Swift libraries are filled with generic code, especially in Apple first-party frameworks such as SwiftUI, Combine, and the recently announced SwiftData. I hope that I’ve made a strong case that generics in Swift are simply too important to ignore. So without further ado, let’s dive into generics, albeit with a slightly different approach than you might expect.

Explicit and Implicit Types in Swift

Sat, 16 Mar 2024 00:00:00 +0000

Generics are one of the most powerful features in Swift, yet they can often feel overwhelming, even for seasoned Swift developers. In this series we’ll learn how to make generics simple, useful, and even fun!

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But to start off, we’ll look somewhere you probably won’t expect: declaring variables.

let strings = ["John", "Paul", "George", "Ringo"]
let oneLongString = strings.joined(separator: ", ")

This seemingly simple piece of code has some hidden functionality. Consider for a second, what type is strings. That’s easy. It’s an Array. But that answer is only half correct. Notice, how does strings know about the joined method? How does it know how to join the elements? What if that was an array of numbers?. Here, most Swift developers would say that the answer is Type Inference. And while that answer is technically correct, it’s still missing part of the story.

Swift Generics Demystified on Daniel Lyons

Concrete and "Soft" Types in Swift

Explicit and Implicit Types in Swift

Back to Basics