Opaque Type: что это, some и any в Swift

func makeInt() -> some Equatable {
    return 42
}

func makeString() -> some Equatable {
    return "Hello"
}

// Compiler knows makeInt returns Int
// makeInt() == makeString() — ❌ error, different types

// Generic: caller chooses type
func identity<T>(_ value: T) -> T { value }
let x: Int = identity(42)

// Opaque: function hides type
func makeSomeEquatable() -> some Equatable { 42 }
let y = makeSomeEquatable()

func areEqual(_ a: some Equatable, _ b: some Equatable) -> Bool {
    // a and b — potentially different types, == won't work directly
    return isEqual(a, b)
}

func isEqual<T: Equatable>(_ a: T, _ b: T) -> Bool {
    return a == b
}

protocol Drawable {
    func draw()
}

// some: static type is known
func makeDrawable() -> some Drawable {
    return Circle() // Single return type
}

// any: dynamic, can store different types
var shapes: [any Drawable] = [Circle(), Square()]
shapes.append(Triangle())

func makeReversedCollection<T>(
    of array: [T]
) -> some Collection {
    return array.reversed()
}

let result = makeReversedCollection(of: [1, 2, 3])
// result — ReversedCollection>, hidden from caller
for item in result {
    print(item)
}

struct ContentView: View {
    var body: some View {
        VStack {
            Text("Hello")
                .font(.title)
            Button("Tap me") {
                print("Tapped")
            }
        }
        .padding()
    }
}