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diff --git a/zh-cn/swift-cn.html.markdown b/zh-cn/swift-cn.html.markdown new file mode 100644 index 00000000..e9dcb858 --- /dev/null +++ b/zh-cn/swift-cn.html.markdown @@ -0,0 +1,226 @@ +--- +language: swift +contributors: + - ["Grant Timmerman", "http://github.com/grant"] +translators: + - ["Xavier Yao", "http://github.com/xavieryao"] +filename: learnswift-cn.swift +--- + +Swift 是Apple 开发的用于iOS 和OS X 开发的编程语言。Swift 于2014年Apple WWDC （全球开发者大会）中被引入，用以与Objective-C 共存，同时对错误代码更具弹性。Swift 由Xcode 6 beta 中包含的LLVM编译器编译。 + +参阅：Apple's [getting started guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/LandingPage/index.html) ——一个完整的Swift 教程 + +```js +// +// 基础 +// + +println("Hello, world") +var myVariable = 42 +let myConstant = 3.1415926 +let explicitDouble: Double = 70 +let label = "some text " + String(myVariable) // Casting +let piText = "Pi = \(myConstant)" // String interpolation +var optionalString: String? = "optional" // Can be nil +optionalString = nil + + +// +// 数组与字典（关联数组） +// + +// 数组 +var shoppingList = ["catfish", "water", "lemons"] +shoppingList[1] = "bottle of water" +let emptyArray = String[]() + +// 字典 +var occupations = [ + "Malcolm": "Captain", + "kaylee": "Mechanic" +] +occupations["Jayne"] = "Public Relations" +let emptyDictionary = Dictionary<String, Float>() + + +// +// 控制流 +// + +// 用于数组的for 循环 +let myArray = [1, 1, 2, 3, 5] +for value in myArray { + if value == 1 { + println("One!") + } else { + println("Not one!") + } +} + +// 用于字典的for 循环 +for (key, value) in dict { + println("\(key): \(value)") +} + +// 用于区间的for 循环 +for i in -1...1 { // [-1, 0, 1] + println(i) +} +// 使用 .. 表示的区间不包含最后一个元素 [-1,0,1) + +// while 循环 +var i = 1 +while i < 1000 { + i *= 2 +} + +// do-while 循环 +do { + println("hello") +} while 1 == 2 + +// Switch +let vegetable = "red pepper" +switch vegetable { +case "celery": + let vegetableComment = "Add some raisins and make ants on a log." +case "cucumber", "watercress": + let vegetableComment = "That would make a good tea sandwich." +case let x where x.hasSuffix("pepper"): + let vegetableComment = "Is it a spicy \(x)?" +default: // 必须 (为了覆盖所有可能的输入) + let vegetableComment = "Everything tastes good in soup." +} + + +// +// 函数 +// + +// 函数是一等类型，这意味着可以在函数中构建函数 +// 并且可以被传递 + +// 函数 +func greet(name: String, day: String) -> String { + return "Hello \(name), today is \(day)." +} +greet("Bob", "Tuesday") + +// 使用多元数组返回多返回值的函数 +func getGasPrices() -> (Double, Double, Double) { + return (3.59, 3.69, 3.79) +} + +// 不定参数 +func setup(numbers: Int...) {} + +// 传递、返回函数 +func makeIncrementer() -> (Int -> Int) { + func addOne(number: Int) -> Int { + return 1 + number + } + return addOne +} +var increment = makeIncrementer() +increment(7) + + +// +// 闭包 +// + +// 函数是特殊的闭包({}) + +// 闭包示例. +// `->` 分隔参数和返回类型 +// `in` 分隔闭包头和闭包体 +numbers.map({ + (number: Int) -> Int in + let result = 3 * number + return result + }) + +// 当类型已知时，可以这样做： +var numbers = [1, 2, 6] +numbers = numbers.map({ number in 3 * number }) +print(numbers) // [3, 6, 18] + + +// +// 类 +// + +// 类的全部方法和属性都是public 的 +// 如果你在一个数据结构中只需储存数据， +// 应使用 `struct` + +// 集成自`Shape` 类的简单的类`Square +class Rect: Shape { + var sideLength: Int = 1 + + // Custom getter and setter property + var perimeter: Int { + get { + return 4 * sideLength + } + set { + sideLength = newValue / 4 + } + } + + init(sideLength: Int) { + super.init() + self.sideLength = sideLength + } + + func shrink() { + if sideLength > 0 { + --sideLength + } + } + + override func getArea() -> Int { + return sideLength * sideLength + } +} +var mySquare = new Square(sideLength: 5) +print(mySquare.getArea()) // 25 +mySquare.shrink() +print(mySquare.sideLength) // 4 + +// 如果你不需要自定义getter 和setter, +// 但仍希望在获取或设置一个属性之前或之后运行 +// 一些代码，你可以使用`willSet` 和 `didSet` + + +// +// 枚举类型 +// + +// 枚举类型可以是某种指定的类型，抑或自成一种类型 +// 像类一样，枚举类型可以包含方法 + +enum Suit { + case Spades, Hearts, Diamonds, Clubs + func getIcon() -> String { + switch self { + case .Spades: return "♤" + case .Hearts: return "♡" + case .Diamonds: return "♢" + case .Clubs: return "♧" + } + } +} + + +// +// 其它 +// + +// `协议(protocol)`: 与Java 的接口(Interface) 类似. +// `扩展(extension)`: 为现有类型添加额外特性 +// 泛型: 与Java 相似。使用`where` 关键字指定 +// 泛型的要求. + +```
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