Swift之协议(Protocols)

// 如果你为doesNotNeedToBeSettable只读属性实现了setter,也不会报错

protocol SomeProtocol {

    var musBeSettable: Int {get set }

    var doesNotNeedToBeSettable: Int { get }

    

}

protocol AnotherProtocol {

    class var someTypeProperty:Int { get set }

    

}

protocol FullyNamed {

    var fullName: String {get }

}

//遵守协议者，必须要有一个fullName的属性

struct Person: FullyNamed {

    var fullName: String

}

var john = Person(fullName:"John Appleseed")

// 把FullyNamed协议的属性现实为计算属性

class Startship: FullyNamed {

    var prefix: String?

    var name: String

    init(name: String, prefix:String? = nil) {

        self.name = name

        self.prefix = prefix

        

    }

    var fullName: String {

        return (prefix !=nil ? prefix! + " " : " ") + name

    }

}

var ncc1701 = Startship(name:"Enterprise", prefix: "USS")

ncc1701.fullName  // "USS Enterprise"