ios – Swift：等价泛型类型的数组

我一直在与 Swift上的一些关于泛型的问题进行斗争,我找不到如何实现这个目标的方法：

>我有一个班级商店< S：State>其中State是一个简单的协议,它扩展了Equatable协议状态：Equatable.
>我有一个类Logger,我想在其中存储一系列商店以跟踪它们的每个变化,并将它们的状态与旧值进行比较,从而能够检查每次迭代中的哪些变化.

为此,我需要在我的记录器类中存储Any Kind of Store的数组.当我尝试使用val storeArray = [Store< Any>]时出现问题,它不起作用,因为Any不是Equatable类型,我将需要它们来扩展Equatable或NSObject以便能够比较两者之间的状态他们.

有可能在Swift中实现这一点吗？或者找出另一种方法来比较2个项目,而不是通用扩展Equatable协议？

如果你想检查实现：

州：

protocol State: Equatable {
}

商店：

class Store<S: State> {

    private var _initialState: S
    private var _state: S
    private var processor = PublishSubject<S>()

    init(initialState: S) {
        _initialState = initialState
        _state = initialState
    }

    var state: S {
        get {
            return _state
        }
        set(value) {
            if (value != state) {
                _state = value
                processor.onNext(value)
            }
        }
    }

    func initialState() -> S {
        return _initialState
    }

    /// Initialize the store. Called after all stores instances are ready.
    func initialize() {
        //TODO Check if its possible to force an override over a method
        preconditionFailure("This method must be overridden")
    }
}

在Vadian的建议之后,我试图将其移动到具有关联类型的协议：

protocol Store: class {
    associatedtype State : StateDelegate
    var processor : PublishSubject<State> { get }
    var _state : State { get set }
    var state: State { get set }
    func initialState() -> State
    func flowable() -> Observable<State>
    func initialize() -> Void
}

extension Store {

    var state: State {
        get {
            return _state
        }
        set(value) {
            if (value != state) {
                _state = value
                processor.onNext(value)
            }
        }
    }

    func flowable() -> Observable<State> {
        return processor.startWith(state)
    }

    func initialState() -> State {
        return State.init()
    }
}

但是当我尝试创建[Store]数组时,我检索到下一个错误：
协议“存储”只能用作通用约束,因为它具有自身或相关类型要求

protocol State {
  func isEqualTo(_ other: State) -> Bool
}

struct State1: State {
  var foo: String
  func isEqualTo(_ other: State) -> Bool {
    guard let state1 = other as? State1 else { return false }
    return self.foo == state1.foo
  }
}

let states: [State] = [ State1(foo: "hi"),State2(bar: 42),State1(foo: "bye")]
let newState = State2(bar: 42)
let containsNewState = states.contains { $0.isEqualTo(newState )}