swift-language

Core Swift language features and modern syntax patterns targeting Swift 5.9+ through Swift 6. Covers language constructs, type system features, Codable, string and collection APIs, and formatting. For concurrency (actors, async/await, Sendable), see the swift-concurrency skill. For SwiftUI views and state management, see swiftui-patterns.

Swift 5.9+ allows if and switch as expressions that return values. Use them to assign, return, or initialize directly.

Swift 6+ allows specifying the error type a function throws.

Apply modern Swift language patterns and idioms for non-concurrency, non-SwiftUI code. Covers if/switch expressions (Swift 5.9+), typed throws (Swift 6+), result builders, property wrappers, opaque and existential types (some vs any), guard patterns, Never type, Regex builders (Swift 5.7+), Codable best practices (CodingKeys, custom decoding, nested containers), modern collection APIs (count(where:), contains(where:), replacing()), FormatStyle (.formatted() on dates, numbers, measurements), and string interpolation patterns. Use when writing core Swift code involving generics, protocols, enums, closures, or modern language features. Source: dpearson2699/swift-ios-skills.