Added swift docs

swift.html.markdown

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+---
+language: swift
+contributors:
+  - ["Grant Timmerman", "http://github.com/grant"]
+filename: learnswift.swift
+---
+
+Swift is a programming language for iOS and OS X development created by Apple. Designed to coexist with Objective-C and to be more resilient against erroneous code, Swift was introduced in 2014 at Apple's developer conference WWDC. It is built with the LLVM compiler included in Xcode 6 beta.
+
+See also Apple's [getting started guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/LandingPage/index.html), which has a complete tutorial on Swift.
+
+# Overview
+- [Basics](#basics)
+- [Arrays and Dictionaries](#array)
+- [Control Flow](#control)
+- [Functions](#func)
+- [Closures](#closures)
+- [Classes](#classes)
+- [Enums](#enums)
+- [Other](#other)
+- [Links](#links)
+
+## <a name="basics"></a>Basics
+
+```js
+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
+```
+
+## <a name="array"></a>Arrays and Dictionaries
+
+```js
+// Array
+var shoppingList = ["catfish", "water", "lemons"]
+shoppingList[1] = "bottle of water"
+let emptyArray = String[]()
+
+// Dictionary
+var occupations = [
+  "Malcolm": "Captain",
+  "kaylee": "Mechanic"
+]
+occupations["Jayne"] = "Public Relations"
+let emptyDictionary = Dictionary<String, Float>()
+```
+
+## <a name="control"></a>Control Flow
+
+```js
+// for loop (array)
+let myArray = [1, 1, 2, 3, 5]
+for value in myArray {
+  if value == 1 {
+    println("One!")
+  } else {
+    println("Not one!")
+  }
+}
+
+// for loop (dictionary)
+for (key, value) in dict {
+  println("\(key): \(value)")
+}
+
+// for loop (range)
+for i in -1...1 { // [-1, 0, 1]
+  println(i)
+}
+// use .. to exclude the last number
+
+// while loop
+var i = 1
+while i < 1000 {
+  i *= 2
+}
+
+// do-while loop
+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: // required (in order to cover all possible input)
+  let vegetableComment = "Everything tastes good in soup."
+}
+```
+
+## <a name="functions"></a>Functions
+
+Functions are a first-class type, meaning they can be nested in functions and can be passed around
+
+```js
+// Function
+func greet(name: String, day: String) -> String {
+  return "Hello \(name), today is \(day)."
+}
+greet("Bob", "Tuesday")
+
+// Function that returns multiple items in a tuple
+func getGasPrices() -> (Double, Double, Double) {
+  return (3.59, 3.69, 3.79)
+}
+
+// Args
+func setup(numbers: Int...) {}
+
+// Passing and returning functions
+func makeIncrementer() -> (Int -> Int) {
+  func addOne(number: Int) -> Int {
+    return 1 + number
+  }
+  return addOne
+}
+var increment = makeIncrementer()
+increment(7)
+```
+
+## <a name="closures"></a>Closures
+
+Functions are special case closures ({})
+
+```js
+// Closure example.
+// `->` separates the arguments and return type
+// `in` separates the closure header from the closure body
+numbers.map({
+  (number: Int) -> Int in
+  let result = 3 * number
+  return result
+  })
+
+// When the type is known, like above, we can do this
+var numbers = [1, 2, 6]
+numbers = numbers.map({ number in 3 * number })
+print(numbers) // [3, 6, 18]
+```
+
+## <a name="classes"></a>Classes
+
+All methods and properties of a class are public. If you just need to store data
+in a structured object, you should use a `struct`
+
+```js
+// A simple class `Square` extends `Shape
+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
+
+// If you don't need a custom getter and setter, but still want to run code
+// before an after getting or setting a property, you can use `willSet` and `didSet`
+```
+
+## <a name="enums"></a>Enums
+
+Enums can optionally be of a specific type or on their own. They can contain methods like classes.
+
+```js
+enum Suit {
+  case Spades, Hearts, Diamonds, Clubs
+  func getIcon() -> String {
+    switch self {
+    case .Spades: return "♤"
+    case .Hearts: return "♡"
+    case .Diamonds: return "♢"
+    case .Clubs: return "♧"
+    }
+  }
+}
+```
+
+## <a name="other"></a>Other
+
+- **`protocol`**: Similar to Java interfaces.
+- **`extension`s**: Add extra functionality to an already created type
+- **Generics**: Similar to Java. Use the `where` keyword to specify the requirements of the generics.
+
+## <a name="links"></a>Links
+
+- [Homepage](https://developer.apple.com/swift/)
+- [Guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/LandingPage/index.html)
+- [Book](https://itunes.apple.com/us/book/the-swift-programming-language/id881256329?mt=11)