That’s right. I was about to say something similar about the Of. Actually Type<T> would be the correct name for the static/concrete metatype.
We already have this notation but not in a generic way T.Type If we add of only in our mind to Type<T>, we’ll get “Type of a type T” which is shortly referred as a “metatype of T”. (Array<Element> - Array of Element type) Since Subtype<T> in reality is some *existential metatype* and the whole talk about existential types now tend to have the Any prefix, lets follow that trend here too. Type<T> - (static/concrete/exact) metatype. AnyType<T> - existential metatype. It might be even easier to memorise this name than Subtype. The example from the proposal rewritten: // Types: protocol Foo {} protocol Boo : Foo {} class A : Foo {} class B : A, Boo {} struct S : Foo {} // Metatypes: let a1: Type<A> = A.self //=> Okay let p1: Type<Foo> = Foo.self //=> Okay let p2: Type<Boo> = C.self //=> Error -- `C` is not the same as `Foo` let any_1: AnyType<Any> = A.self //=> Okay let any_2: AnyType<Any> = Foo.self //=> Okay let a_1: AnyType<A> = A.self //=> Okay let p_1: AnyType<Foo> = A.self //=> Okay let p_2: AnyType<Foo> = Foo.self //=> Error -- `Type<Foo>` is not a subtype of `AnyType<Foo>` // Generic functions: func dynamic<T>(type: AnyType<Any>, `is` _: Type<T>) -> Bool { return type is AnyType<T> } func dynamic<T>(type: AnyType<Any>, `as` _: Type<T>) -> AnyType<T>? { return type as? AnyType<T> } let s1: Type<S> = S.self dynamic(type: s1, is: Foo.self) //=> true dynamic(type: s1, as: Foo.self) //=> an `Optional<AnyType<Foo>>` The type(of:) function could now stay, because now we’d only need to change the return type. func type<T>(of instance: T) -> AnyType<T> Isn’t this a good compromise? -- Adrian Zubarev Sent with Airmail Am 2. Oktober 2016 um 09:01:45, Pyry Jahkola via swift-evolution (swift-evolution@swift.org) schrieb: OTOH, we don't have ArrayOf<Element> or DictionaryOfKeyAndValue<Key, Value>, while we still pronounce them that way. I don't think prepositions belong in the name of types but in exceptional cases, and this doesn't sound exceptional enough to me.
_______________________________________________ swift-evolution mailing list swift-evolution@swift.org https://lists.swift.org/mailman/listinfo/swift-evolution