What is the `some` keyword in Swift(UI)?

Question

The new SwiftUI tutorial has the following code:

struct ContentView: View {
    var body: some View {
        Text(         


        

Answer 1

The some keyword from Swift 5.1 (swift-evolution proposal) is used in conjunction with a Protocol as a return type.

Xcode 11 release notes present it like that:

Functions can now hide their concrete return type by declaring what protocols it conforms to, instead of specifying the exact return type:

func makeACollection() -> some Collection {
    return [1, 2, 3]
}

Code that calls the function can use the interface of the protocol, but doesn’t have visibility into the underlying type. (SE-0244, 40538331)

In the example above, you don't need to tell that you're going to return an Array. That allows you to even return a generic type that just conforms to Collection.

---

Note also this possible error that you may face:

'some' return types are only available in iOS 13.0.0 or newer

It means that you're supposed to use availability to avoid some on iOS 12 and before:

@available(iOS 13.0, *)
func makeACollection() -> some Collection {
    ...
}