Question

我在设计Vertex结构时遇到问题。我希望能够创建＆＃34; Array＆＃34;或＆＃34;设置＆＃34;所以我的＆＃34; Vertex＆＃34;并非都必须是同一类型。这两种情况都有不同的错误。检查下面的代码。

提前谢谢

import Foundation

public struct Vertex<T: Equatable> where  T: Equatable, T: Hashable {

    public var data: T
    public let index: Int?

    init(data: T , index: Int ) {
        self.data = data
        self.index = index
      }

}

extension Vertex: CustomStringConvertible {

    public var description: String {
        return "\(index): \(data)"
    }

}

struct Coordinate {
    var x : Int
    var y : Int

    init(x : Int, y: Int) {
        self.x = x
        self.y = y
    }

}
extension Coordinate: Equatable {}

func ==(lhs: Coordinate, rhs: Coordinate) -> Bool {
    guard lhs.x == rhs.x else {
        return false
    }

    guard lhs.y == rhs.y else {
        return false
    }
    return true
}

extension Coordinate: Hashable {
    var hashValue: Int {
        return "\(x)\(y)".hashValue
    }
}




let coord1  = Coordinate(x : 5, y: 5)
let stringVertex1  = Vertex(data: "Hello World", index: 3)
let stringVertex2  = Vertex(data: "Foo ", index: 3)
let intVertex1  = Vertex(data: 2, index: 1)
let coordVertex1  = Vertex(data: coord1, index: 1)


//Error: Cannot convert value of type 'Vertex<String>' to expected element type 'Vertex'. 
//Even if I make myArr1 equal to [stringVertex1, stringVertex1], I still get the same error.
let myArr1 : Array<Vertex> = [stringVertex1, intVertex1]

//This works since the data inside "Vertex" is the same type.
let myArr2 : Array<Vertex<String>> = [stringVertex1, stringVertex2]

//Error: Type "Vertex" does not conform to protocol "Hashable". 
let mySet1 : Set<Vertex> = [stringVertex1, stringVertex2]

Answer 1

我得到了答案。这是最终的顶点代码。 POP的力量！

public enum TypeOfVertex : String {
    case Int = "Mirror for Int"
    case Float = "Mirror for Float"
    case Double = "Mirror for Double"
    case Coordinates = "Mirror for Coordinate"
    case String = "Mirror for String"

}


protocol AnyVertexable {
    var type: TypeOfVertex { get set }
    var index: Int { get set }

}


struct Vertex<Element : Hashable> : AnyVertexable where Element: Equatable & Hashable {

    var type : TypeOfVertex
    var index: Int
    var data : Element?

    init(index: Int, data: Element) {
        self.data = data
        self.index = index
        if let type = TypeOfVertex(rawValue: data.hashValue.customMirror.description) {
           self.type = type
        } else {
           fatalError()
        }
    }

}

let sample1 = Vertex(index: 0, data: 1.0)
let sample2 = Vertex(index: 2, data: 1)
let sample3 = Vertex(index: 3, data: Coordinate(x: 5, y: 5))

let myArr : [AnyVertexable] = [sample1, sample2, sample3]

如何创建一个通用的顶点，以便我可以创建混合类型的图形（集合）？

1 个答案: