Diversity

https://swift.org/diversity/

Swift Packages

• Use Swift Package Index to search swift packages
• Swift Package collections in Xcode

Swift Package Collections

• anyone can publish them

Apple Swift Packages

Swift Collections

https://github.com/apple/swift-collections

• Deque
• Ordered Set
• Ordered Dictionary

Swift Algorithms

https://github.com/apple/swift-algorithms

Swift System

https://github.com/apple/swift-system

• idiomatic, low-level interfaces to system calls
• strong types, error handling, memory safety
• Linux and Windows support

Swift Numerics

https://github.com/apple/swift-numerics

• Float16 support on Apple silicon Macs

Swift ArgumentParser

https://github.com/apple/swift-argument-parser

• Fish shell completion scripts
• Joined short options (-Ddebug)
• Improved error messages

Update Swift on server

• Static linking on Linux
• Improved JSON performance
• Enhanced AWS Lambda runtime

Developer experience

Swift DocC

Will be open sourced this year(2021).

Build Improvements

• faster builds when changing imported modules
• faster startup time before launching compiles
• fewer recompilations after changing an extension body

Memory Management

• Add Xcode settings: Optimize Object Lifetimes

Ergonomic improvements

Enum Codable synthesis

enum Command: Codable {
    case load(key: String)
    case store(key: String, value: Int)
}

Flexible static member lookup

protocol Coffee { ... }
struct RegularCoffee: Coffee { }
struct Cappuccino: Coffee { }
extension Coffee where Self == Cappucino {
    static var cappucino: Cappucino { Cappucino() }
}

func brew<CoffeeType: Coffee>(_ coffee: CoffeeType) { ... }

brew(.cappucino.large)

Property wrappers on parameters

@propertyWrapper
struct NonEmpty<Value: Collection> {
    init(wrappedValue: Value) {
        precondition(!wrappedValue.isEmpty)
        self.wrappedValue = wrappedValue
    }

    var wrappedValue: Value {
        willSet { precondition(!newValue.isEmpty) }
    }
}

func logIn(@NonEmpty _ username: String) {
    print("Logging in: \(username)")
}

Actors

actor Statistics {
    private var counter: Int = 0
    func increment() {
        counter += 1
    }
    func publish() async {
        await sendResults(counter)
    }
}

var statistics = Statistics()
await statistics.increment()

Reference

• https://developer.apple.com/wwdc21/10192
• https://swift.org/diversity/
• https://swift.org/blog/package-collections