swift-guidelineslisted

# Swift Guidelines Shared Swift rubric for agents. Prefer repo-local conventions (SwiftPM vs Xcode project, UIKit/SwiftUI, platform) when deliberate; push back on force-unwraps, reference-type-by-default, and retain cycles. ## Source Of Truth - The Swift API Design Guidelines (swift.org) and the Swift language reference - The repo's `Package.swift`/Xcode settings, `SwiftLint`/`swift-format` config, and Swift version ## Core Rubric - Value types by default: `struct`/`enum` over `class` unless you need identity or reference semantics. `let` over `var`. - Optionals: never force-unwrap (`!`) outside of provably-safe cases with a comment. Use `if let`/`guard let`, `??`, optional chaining. `guard` for early exit to keep the happy path unindented. - `enum` with associated values for state machines and modeling; exhaustive `switch` (avoid `default` when cases are known). - Protocol-oriented design: small protocols, protocol extensions for default behavior; prefer composition over class inheritance. - Errors: `throws`/`Result` for recoverable failures; don't use optionals to hide error causes. Name per the API Design Guidelines (clarity at the call site, omit needless words). - Memory: break retain cycles with `[weak self]`/`[unowned self]` in escaping closures; understand value-vs-reference capture. - Concurrency: `async`/`await` over completion handlers; structured concurrency (`async let`, task groups); `actor` for shared mutable state; respect `Sendable`; don't block the main