Swift里的protocol--协议

我感觉它和java或go里的接口，差不多一个意思吧。

protocol FullyNamed { var fullName: String { get } } struct Person: FullyNamed { var fullName: String } class Starship: 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 = Starship(name: "Enterprise", prefix: "USS") print(ncc1701.fullName) let john = Person(fullName: "John Appleseed") print(john.fullName) protocol RandomNumberGenerator { func random() -> Double } class LinearCongruentialGenerator: RandomNumberGenerator { var lastRandom = 42.0 let m = 139968.0 let a = 3877.0 let c = 29573.0 func random() -> Double { lastRandom = (lastRandom * a + c) return lastRandom / m } } let generator = LinearCongruentialGenerator() print("Here's random number: \(generator.random())") print("And another one: \(generator.random())") protocol Togglable { mutating func toggle() } enum OnOffSwitch: Togglable { case Off, On mutating func toggle() { switch self { case Off: self = On case On: self = Off } } } var lightSwitch = OnOffSwitch.Off lightSwitch.toggle() print(lightSwitch)