我不确定如何进行以下工作。 （Swift 3，XCode8）。
我正在尝试创建通用Node类，它将状态对象和/或线框对象作为通用参数，状态对象具有作为NodeState的协议约束。
我收到以下错误：
Cannot convert value of type Node<State, Wireframe> to type Node<_,_> in coercion
使用以下代码（应该在Playground中运行）：
import Foundation
public protocol NodeState {
associatedtype EventType
associatedtype WireframeType
mutating func action(_ event: EventType, withNode node: Node<Self, WireframeType>)
}
extension NodeState {
mutating public func action(_ event: EventType, withNode node: Node<Self, WireframeType>) { }
}
public class Node<State: NodeState, Wireframe> {
public var state: State
public var wireframe: Wireframe?
public init(state: State, wireframe: Wireframe?) {
self.state = state
guard wireframe != nil else { return }
self.wireframe = wireframe
}
public func processEvent(_ event: State.EventType) {
DispatchQueue.main.sync { [weak self] in
// Error presents on the following
let node = self! as Node<State, State.WireframeType>
self!.state.action(event, withNode: node)
}
}
}
非常感谢任何帮助。谢谢！
更新：
以下工作 - 当我删除线框引用时：
import Foundation
public protocol NodeState {
associatedtype EventType
mutating func action(_ event: EventType, withNode node: Node<Self>)
}
extension NodeState {
mutating public func action(_ event: EventType, withNode node: Node<Self>) { }
}
public class Node<State: NodeState> {
public var state: State
public init(state: State) {
self.state = state
}
public func processEvent(_ event: State.EventType) {
DispatchQueue.main.sync { [weak self] in
self!.state.action(event, withNode: self!)
}
}
}
现在，如何添加将通用Wireframe对象添加到Node类的选项？
答案 0 :(得分：0)
应用我怀疑的是Hamish的回答，现在按预期编译。谢谢！
import Foundation
public protocol NodeState {
associatedtype EventType
associatedtype WireframeType
mutating func action(_ event: EventType, withNode node: Node<Self>)
}
extension NodeState {
mutating public func action(_ event: EventType, withNode node: Node<Self>) { }
}
public class Node<State: NodeState> {
public var state: State
public var wireframe: State.WireframeType?
public init(state: State, wireframe: State.WireframeType?) {
self.state = state
guard wireframe != nil else { return }
self.wireframe = wireframe
}
public func processEvent(_ event: State.EventType) {
DispatchQueue.main.sync { [weak self] in
self!.state.action(event, withNode: self!)
}
}
}