whats generics

Generics in Swift allow you to write flexible and reusable code by enabling you to define functions, types, and protocols that can work with any type. Here are some key points about generics from the WWDC sessions:

1. Basic Concept:

   • Generics enable you to write functions and types that can operate on any type, specified as a placeholder. For example, a generic function might look like this:

     func execute<T>(item: T) {
         // Function body
     }
     

     Here, T is a placeholder for any type.

2. Constraints:

   • You can add constraints to generics to specify that the placeholder type must conform to certain protocols. For example, you might require that a type conforms to the Hashable protocol:

     func uniqued<T: Hashable>(items: [T]) -> [T] {
         // Function body
     }
     

     This ensures that the function can only be called with types that conform to Hashable.

3. Noncopyable Generics:

   • Swift 6 introduces noncopyable generics, which allow you to define generics that do not require the types to be copyable. This is useful for types that manage resources and should not be copied.
   • For example, you can define a generic function that works with noncopyable types by using the ~copyable constraint:

     func execute<T: ~copyable>(item: T) {
         // Function body
     }
     

     This broadens the types permitted by the function to include noncopyable types.

4. Embedded Swift:

   • Generics are fully supported in Embedded Swift, allowing you to write efficient and reusable code even in constrained environments. The compiler can specialize generic functions to avoid runtime overhead.

For more detailed information, you can refer to the following sessions:

• Consume noncopyable types in Swift
• A Swift Tour: Explore Swift’s features and design
• Go small with Embedded Swift

These sessions provide a comprehensive overview of generics, their constraints, and their applications in different contexts.