Swift — Require classes implementing protocol to be subclasses of a certain class

Question

I\'m creating several NSView classes, all of which support a special operation, which we\'ll call transmogrify. At first glance, this seems like t

Answer 1

check this solution here... Swift - class method which must be overridden by subclass

This solution allows to inherit from a class and also to have the protocol's compile time check. :)

Answer 2

There is a workaround by using associated types to enforce the subclass:

protocol TransmogrifiableView {
    associatedtype View: NSView = Self
    func transmogrify()
}

class MyView: NSView, TransmogrifiableView { ... } // compiles
class MyOtherClass: TransmogrifiableView { ... } // doesn't compile