Swift AnyObject - 将协议(protocol)数组向下转换为 [AnyObject]

Question

如何将协议(protocol)实例数组向下转换为 AnyObject？我在下面的代码示例中尝试了一些更合理的想法。

protocol Nameable : class {
    var name: String { get }
}

class Person: Nameable {
    var name: String

    init(name: String)
    {
        self.name = name
    }
}

class Example {

    func setArray(array: [AnyObject]?, forKey: String)
    {
        print("hello world")
    }
}

var personOne = Person(name: "Evan")
var personTwo = Person(name: "Brian")

var array: [ Nameable ] = [ personOne, personTwo ]

var anotherArray = array.map({ $0 as AnyObject })    // OMG gross!
var yetAnotherArray = array as [ AnyObject ]         // Nope.
var evenYetAnotherArray = array as? [ AnyObject ]    // Nope.
var omgThisIsAnArray = Array<AnyObject>(array)       // Ha ha, srsly. Nope.

var myExample = Example()
myExample.setArray(anotherArray, forKey: "Named")

就其值(value)而言，setArray(_ anArray: [AnyObject]?, forKey aKey: String) 方法签名来自 Apple 的 NSUbiquitousKeyValueStore 类，所以我不能真正重新设计它是类型安全的。

Answer 1

它并不完美，但如果协议(protocol)和类都是@objc(以及类的子类NSObject)，它就可以工作:

@objc protocol Nameable: class {
    var name: String { get }
}

@objc class Person: NSObject, Nameable {
    var name: String
    init(name: String) {
        self.name = name
    }
}

...

var array: [Nameable] = [personOne, personTwo]
let array2 = array as [AnyObject] // ✓