raywenderlich.com的Swift编程风格指南

let MaximumWidgetCount = 100

class WidgetContainer {
  var widgetButton: UIButton
  let widgetHeightPercentage = 0.85
}

let MAX_WIDGET_COUNT = 100

class app_widgetContainer {
  var wBut: UIButton
  let wHeightPct = 0.85
}

func dateFromString(dateString: NSString) -> NSDate
func convertPointAt(column: Int, row: Int) -> CGPoint
func timedAction(delay: NSTimeInterval, perform action: SKAction) -> SKAction!

// would be called like this:
dateFromString("2014-03-14")
convertPointAt(column: 42, row: 13)
timedAction(delay: 1.0, perform: someOtherAction)

class Guideline {
  func combineWithString(incoming: String, options: Dictionary?) { ... }
  func upvoteBy(amount: Int) { ... }
}

import MyModule

var myClass = MyModule.MyClass()

@objc (RWTChicken) class Chicken {
   ...
}

• 使用2个空格来缩进，而不是用tab，这能够节省空间，并有助于防止换行。

  请务必在Xcode的偏好设置里设置。

• 方法的大括号和其它语句的大括号（if / else / switch / while等等）总是和语句在同一行打开，在新的一行关闭。

建议：

if user.isHappy {
  //Do something
} else {
  //Do something else
}

if user.isHappy
{
    //Do something
}
else {
    //Do something else
}

• 在方法之间应该正好有一个空行。这能使结构看起来更加清晰。

  在方法内用空行分隔功能。但假设分隔成太多段的话，经常意味着你须要把一个方法重构成多个方法。

class Circle: Shape {
  var x: Int, y: Int
  var radius: Double
  var diameter: Double {
    get {
      return radius * 2
    }
    set {
      radius = newValue / 2
    }
  }

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

  convenience init(x: Int, y: Int, diameter: Double) {
    self.init(x: x, y: y, radius: diameter / 2)
  }

  func describe() -> String {
    return "I am a circle at \(centerString()) with an area of \(computeArea())"
  }

  override func computeArea() -> Double {
    return M_PI * radius * radius
  }

  private func centerString() -> String {
    return "(\(x),\(y))"
  }
}

• 为属性、变量、常量、參数定义以及其它申明指定类型的时候，在冒号后面而不是前面添加一个空格，比方：x: Int 和 Circle: Shape。
• 对于多个变量，假设它们有相同的结构和上下文环境（比方x、y），则把它们定义在同一行。
• 缩进属性（property）的getter/setter定义。
• 不要加入像interal这种默认修饰符。相同的，当覆盖一个方法时。不要在方法上再次写上它的訪问修饰符。

class BoardLocation {
  let row: Int, column: Int

  init(row: Int,column: Int) {
    self.row = row
    self.column = column
  }
}

func reticulateSplines(spline: [Double]) -> Bool {
  // reticulate code goes here
}

func reticulateSplines(spline: [Double], adjustmentFactor: Double,
    translateConstant: Int, comment: String) -> Bool {
  // reticulate code goes here
}

在不论什么情况下，给闭包中的參数具有描写叙述性的名称：

return SKAction.customActionWithDuration(effect.duration) { node, elapsedTime in 
  // more code goes here
}

attendeeList.sort { a, b in
  a > b
}

Swift提供了桥接（Bridging）到Objective-C的功能，在须要时你也能使用Objective-C的完整方法：

let width = 120.0                                    //Double
let widthString = (width as NSNumber).stringValue    //String

不建议：

let width: NSNumber = 120.0                                 //NSNumber
let widthString: NSString = width.stringValue               //NSString

myOptional?
.anotherOne?.optionalView?.setNeedsDisplay()

if let view = self.optionalView {
  // do many things with view
}

let bounds = CGRect(x: 40, y: 20, width: 120, height: 80)
var centerPoint = CGPoint(x: 96, y: 42)

let bounds = CGRectMake(40, 20, 120, 80)
var centerPoint = CGPointMake(96, 42)

let message = "Click the button"
var currentBounds = computeViewBounds()

let message: String = "Click the button"
var currentBounds: CGRect = computeViewBounds()

var deviceModels: [String]
var employees: [Int: String]
var faxNumber: Int?

var deviceModels: Array<String>
var employees: Dictionary<Int, String>
var faxNumber: Optional<Int>

for _ in 0..<3 {
  println("Hello three times")
}

for person in attendeeList {
  // do something
}

for var i = 0; i < 3; i++ {
  println("Hello three times")
}

for var i = 0; i < attendeeList.count; i++ {
  let person = attendeeList[i]
  // do something
}

var swift = "not a scripting language"

var swift = "not a scripting language";

var color = "red"

var colour = "red"

:]

:)

• Soheil Moayedi Azarpour
• Scott Berrevoets
• Eric Cerney
• Sam Davies
• Evan Dekhayser
• Jean-Pierre Distler
• Colin Eberhardt
• Greg Heo
• Matthijs Hollemans
• Erik Kerber
• Christopher LaPollo
• Andy Pereira
• Ryan Nystrom
• Cesare Rocchi
• Ellen Shapiro
• Marin Todorov
• Chris Wagner
• Ray Wenderlich
• Jack Wu

• The Swift Programming Language
• Using Swift with Cocoa and Objective-C
• Swift Standard Library Reference