enum打印 CustomStringConvertible

 

CustomStringConvertible协议可以用来打印自定义的类和结构体

  enum DownUpPhase: CustomStringConvertible {
        case MovingDown, MovingUp
        var description: String {
            get {
                switch self {
                case .MovingDown:
                    return "Moving Down"
                case .MovingUp:
                    return "Moving Up"
                }
            }
        }
    }
    var phase: DownUpPhase = .MovingDown
        
     print(phase)
    //输出：Moving Down