swift-patterns

Guard let and if let are Swift's safe unwrapping patterns that check for nil before accessing a value. Guard let exits early if nil is found, while if let binds the unwrapped value conditionally, preventing crashes and enforcing explicit nil handling.

Protocols define contracts for types, and generics allow functions and structures to work with any conforming type while maintaining type safety. Together they enable reusable, scalable abstractions without sacrificing compile-time type checking.

Capture lists in closures let you specify how variables are captured—typically using [weak self] to prevent strong reference cycles. This is essential in callbacks and completion handlers where closures persist beyond their defining scope.

Optional chaining allows you to call methods and access properties on optionals that may be nil. The operation returns an optional result; if the optional is nil, the call is skipped entirely, providing safe navigation without explicit unwrapping.

Guard let exits early if nil and requires a return or throw; if let binds conditionally within a block. Nil coalescing (??) provides a default non-optional value if the optional is nil, each suited to different control-flow needs.

Yes, optionals, guard let, closures, protocols, and generics are core Swift language features that work identically across iOS, macOS, and other Apple platforms, ensuring consistency across multi-platform development.