SE-0343 upgrades Swift’s support for top-level code – think main.swift in a macOS Command Line Tool project – so that it supports concurrency out of the box. This is one of those changes that might seem trivial on the surface, but took a lot of work to make happen.
In practice, it means you can write code like this directly into your main.swift files:
import Foundation
let url = URL(string: "https://hws.dev/readings.json")!
let (data, _) = try await URLSession.shared.data(from: url)
let readings = try JSONDecoder().decode([Double].self, from: data)
print("Found \(readings.count) temperature readings")Previously, we had to create a new @main struct that had an asynchronous main() method, so this new, simpler approach is a big improvement.
SAVE 50% All our books and bundles are half price for Black Friday, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.
Other changes in Swift 5.7…
- if let shorthand for unwrapping optionals
- Multi-statement closure type inference
- Clock, Instant, and Duration
- Regular expressions
- Type inference from default expressions
- Opaque parameter declarations
- Structural opaque result types
- Unlock existentials for all protocols
- Lightweight same-type requirements for primary associated types
- Constrained existential types
- Distributed actor isolation
- buildPartialBlock for result builders
- Implicitly opened existentials
- Unavailable from async attribute
Download all Swift 5.7 changes as a playground Link to Swift 5.7 changes
