@dynamicMemberLookup
struct Apply<Base: AnyObject> {
    private let build: () -> Base

    private init(_ build: @escaping () -> Base) {
        self.build = build
    }

    init(_ base: Base) {
        self.build = { base }
    }

    subscript<Value>(dynamicMember keyPath: ReferenceWritableKeyPath<Base, Value>) -> (Value) -> Apply<Base> {
        { [build = build] value in
            Apply {
                let object = build()
                object[keyPath: keyPath] = value
                return object
            }
        }
    }

    func apply() -> Base {
        build()
    }
}

protocol Applicatable {
    associatedtype Target: AnyObject
    func apply(_ closure: ((Apply<Target>) -> Apply<Target>)) -> Target
}

extension Applicatable where Self: AnyObject {
    func apply(_ closure: ((Apply<Self>) -> Apply<Self>)) -> Self {
        _ = closure(Apply(self)).apply()
        return self
    }
}

extension NSObject: Applicatable {}