Swift Language Patterns

Apply modern Swift 6.4 syntax and idioms (Swift 6.4 / Xcode 27 additions: references/swift-6-4.md) without altering behavior or evaluation order. Route concurrency to swift-concurrency, deep serialization to swift-codable, formatting to swift-formatstyle, naming to swift-api-design-guidelines, and SwiftUI state to swiftui-patterns.

Contents

• Expressions & Control Flow
• Typed Throws (Swift 6+)
• Opaque vs Existential Types
• Result Builders & Property Wrappers
• Modern Collections & Regex
• Common Mistakes
• Review Checklist
• References

Expressions & Control Flow

Use value-producing if and switch expressions for direct assignment, initialization, and single-expression returns: