1 files changed, 72 insertions, 47 deletions
diff --git a/swift.html.markdown b/swift.html.markdown
index ffc57e69..f451288d 100644
--- a/swift.html.markdown
+++ b/swift.html.markdown
@@ -3,7 +3,9 @@ language: swift
 contributors:
   - ["Grant Timmerman", "http://github.com/grant"]
   - ["Christopher Bess", "http://github.com/cbess"]
-  - ["Joey Huang", "http://github.com/kamidox"]  
+  - ["Joey Huang", "http://github.com/kamidox"]
+  - ["Anthony Nguyen", "http://github.com/anthonyn60"]
+  - ["Clayton Walker", "https://github.com/cwalk"]
 filename: learnswift.swift
 ---
 
@@ -11,7 +13,7 @@ Swift is a programming language for iOS and OS X development created by Apple. D
 
 The official [Swift Programming Language](https://itunes.apple.com/us/book/swift-programming-language/id881256329) book from Apple is now available via iBooks.
 
-See also Apple's [getting started guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/RoadMapiOS/index.html), which has a complete tutorial on Swift.
+See also Apple's [getting started guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/DevelopiOSAppsSwift/), which has a complete tutorial on Swift.
 
 ```swift
 // import a module
@@ -26,7 +28,9 @@ import UIKit
 // TODO: Do something soon
 // FIXME: Fix this code
 
-println("Hello, world")
+// In Swift 2, println and print were combined into one print method. Print automatically appends a new line.
+print("Hello, world") // println is now print
+print("Hello, world", appendNewLine: false) // printing without appending a newline
 
 // variables (var) value can change after being set
 // constants (let) value can NOT be changed after being set
@@ -46,16 +50,17 @@ let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation
 // Build Specific values
 // uses -D build configuration
 #if false
-    println("Not printed")
+    print("Not printed")
     let buildValue = 3
 #else
     let buildValue = 7
 #endif
-println("Build value: \(buildValue)") // Build value: 7
+print("Build value: \(buildValue)") // Build value: 7
 
 /*
-    Optionals are a Swift language feature that allows you to store a `Some` or
-    `None` value.
+    Optionals are a Swift language feature that either contains a value,
+    or contains nil (no value) to indicate that a value is missing.
+    A question mark (?) after the type marks the value as optional.
 
     Because Swift requires every property to have a value, even nil must be
     explicitly stored as an Optional value.
@@ -69,13 +74,19 @@ var someOptionalString2: Optional<String> = "optional"
 if someOptionalString != nil {
     // I am not nil
     if someOptionalString!.hasPrefix("opt") {
-        println("has the prefix")
+        print("has the prefix")
     }
-    
+
     let empty = someOptionalString?.isEmpty
 }
 someOptionalString = nil
 
+/*
+    Trying to use ! to access a non-existent optional value triggers a runtime 
+    error. Always make sure that an optional contains a non-nil value before
+    using ! to force-unwrap its value.
+*/
+
 // implicitly unwrapped optional
 var unwrappedString: String! = "Value is expected."
 // same as above, but ! is a postfix operator (more syntax candy)
@@ -90,13 +101,13 @@ if let someOptionalStringConstant = someOptionalString {
 
 // Swift has support for storing a value of any type.
 // AnyObject == id
-// Unlike Objective-C `id`, AnyObject works with any value (Class, Int, struct, etc)
+// Unlike Objective-C `id`, AnyObject works with any value (Class, Int, struct, etc.)
 var anyObjectVar: AnyObject = 7
 anyObjectVar = "Changed value to a string, not good practice, but possible."
 
 /*
     Comment here
-    
+
     /*
         Nested comments are also supported
     */
@@ -138,21 +149,21 @@ var emptyMutableDictionary = [String: Float]() // var == mutable
 let myArray = [1, 1, 2, 3, 5]
 for value in myArray {
     if value == 1 {
-        println("One!")
+        print("One!")
     } else {
-        println("Not one!")
+        print("Not one!")
     }
 }
 
 // for loop (dictionary)
 var dict = ["one": 1, "two": 2]
 for (key, value) in dict {
-    println("\(key): \(value)")
+    print("\(key): \(value)")
 }
 
 // for loop (range)
 for i in -1...shoppingList.count {
-    println(i)
+    print(i)
 }
 shoppingList[1...2] = ["steak", "peacons"]
 // use ..< to exclude the last number
@@ -165,7 +176,7 @@ while i < 1000 {
 
 // do-while loop
 do {
-    println("hello")
+    print("hello")
 } while 1 == 2
 
 // Switch
@@ -222,8 +233,8 @@ let pricesTuple = getGasPrices()
 let price = pricesTuple.2 // 3.79
 // Ignore Tuple (or other) values by using _ (underscore)
 let (_, price1, _) = pricesTuple // price1 == 3.69
-println(price1 == pricesTuple.1) // true
-println("Gas price: \(price)")
+print(price1 == pricesTuple.1) // true
+print("Gas price: \(price)")
 
 // Variadic Args
 func setup(numbers: Int...) {
@@ -251,7 +262,7 @@ func swapTwoInts(inout a: Int, inout b: Int) {
 var someIntA = 7
 var someIntB = 3
 swapTwoInts(&someIntA, &someIntB)
-println(someIntB) // 7
+print(someIntB) // 7
 
 
 //
@@ -292,10 +303,10 @@ print(numbers) // [3, 6, 18]
 // MARK: Structures
 //
 
-// Structures and classes have very similar capabilites
+// Structures and classes have very similar capabilities
 struct NamesTable {
     let names = [String]()
-    
+
     // Custom subscript
     subscript(index: Int) -> String {
         return names[index]
@@ -305,7 +316,7 @@ struct NamesTable {
 // Structures have an auto-generated (implicit) designated initializer
 let namesTable = NamesTable(names: ["Me", "Them"])
 let name = namesTable[1]
-println("Name is \(name)") // Name is Them
+print("Name is \(name)") // Name is Them
 
 //
 // MARK: Classes
@@ -326,7 +337,7 @@ public class Shape {
 
 internal class Rect: Shape {
     var sideLength: Int = 1
-    
+
     // Custom getter and setter property
     private var perimeter: Int {
         get {
@@ -337,11 +348,11 @@ internal class Rect: Shape {
             sideLength = newValue / 4
         }
     }
-    
+
     // Lazily load a property
     // subShape remains nil (uninitialized) until getter called
     lazy var subShape = Rect(sideLength: 4)
-    
+
     // If you don't need a custom getter and setter,
     // but still want to run code before and after getting or setting
     // a property, you can use `willSet` and `didSet`
@@ -351,19 +362,19 @@ internal class Rect: Shape {
             print(someIdentifier)
         }
     }
-    
+
     init(sideLength: Int) {
         self.sideLength = sideLength
         // always super.init last when init custom properties
         super.init()
     }
-    
+
     func shrink() {
         if sideLength > 0 {
             --sideLength
         }
     }
-    
+
     override func getArea() -> Int {
         return sideLength * sideLength
     }
@@ -386,7 +397,7 @@ let aShape = mySquare as Shape
 
 // compare instances, not the same as == which compares objects (equal to)
 if mySquare === mySquare {
-    println("Yep, it's mySquare")
+    print("Yep, it's mySquare")
 }
 
 // Optional init
@@ -395,13 +406,13 @@ class Circle: Shape {
     override func getArea() -> Int {
         return 3 * radius * radius
     }
-    
+
     // Place a question mark postfix after `init` is an optional init
     // which can return nil
     init?(radius: Int) {
         self.radius = radius
         super.init()
-        
+
         if radius <= 0 {
             return nil
         }
@@ -409,13 +420,13 @@ class Circle: Shape {
 }
 
 var myCircle = Circle(radius: 1)
-println(myCircle?.getArea())    // Optional(3)
-println(myCircle!.getArea())    // 3
+print(myCircle?.getArea())    // Optional(3)
+print(myCircle!.getArea())    // 3
 var myEmptyCircle = Circle(radius: -1)
-println(myEmptyCircle?.getArea())    // "nil"
+print(myEmptyCircle?.getArea())    // "nil"
 if let circle = myEmptyCircle {
     // will not execute since myEmptyCircle is nil
-    println("circle is not nil")
+    print("circle is not nil")
 }
 
 
@@ -447,7 +458,7 @@ enum BookName: String {
     case John = "John"
     case Luke = "Luke"
 }
-println("Name: \(BookName.John.rawValue)")
+print("Name: \(BookName.John.rawValue)")
 
 // Enum with associated Values
 enum Furniture {
@@ -455,7 +466,7 @@ enum Furniture {
     case Desk(height: Int)
     // Associate with String and Int
     case Chair(String, Int)
-    
+
     func description() -> String {
         switch self {
         case .Desk(let height):
@@ -467,9 +478,9 @@ enum Furniture {
 }
 
 var desk: Furniture = .Desk(height: 80)
-println(desk.description())     // "Desk with 80 cm"
+print(desk.description())     // "Desk with 80 cm"
 var chair = Furniture.Chair("Foo", 40)
-println(chair.description())    // "Chair of Foo with 40 cm"
+print(chair.description())    // "Chair of Foo with 40 cm"
 
 
 //
@@ -494,7 +505,7 @@ protocol ShapeGenerator {
 
 class MyShape: Rect {
     var delegate: TransformShape?
-    
+
     func grow() {
         sideLength += 2
 
@@ -522,21 +533,21 @@ extension Square: Printable {
     }
 }
 
-println("Square: \(mySquare)")
+print("Square: \(mySquare)")
 
 // You can also extend built-in types
 extension Int {
     var customProperty: String {
         return "This is \(self)"
     }
-    
+
     func multiplyBy(num: Int) -> Int {
         return num * self
     }
 }
 
-println(7.customProperty) // "This is 7"
-println(14.multiplyBy(3)) // 42
+print(7.customProperty) // "This is 7"
+print(14.multiplyBy(3)) // 42
 
 // Generics: Similar to Java and C#. Use the `where` keyword to specify the
 //   requirements of the generics.
@@ -550,7 +561,7 @@ func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? {
     return nil
 }
 let foundAtIndex = findIndex([1, 2, 3, 4], 3)
-println(foundAtIndex == 2) // true
+print(foundAtIndex == 2) // true
 
 // Operators:
 // Custom operators can start with the characters:
@@ -566,9 +577,23 @@ prefix func !!! (inout shape: Square) -> Square {
 }
 
 // current value
-println(mySquare.sideLength) // 4
+print(mySquare.sideLength) // 4
 
 // change side length using custom !!! operator, increases size by 3
 !!!mySquare
-println(mySquare.sideLength) // 12
+print(mySquare.sideLength) // 12
+
+// Operators can also be generics
+infix operator <-> {}
+func <-><T: Equatable> (inout a: T, inout b: T) {
+    let c = a
+    a = b
+    b = c
+}
+
+var foo: Float = 10
+var bar: Float = 20
+
+foo <-> bar
+print("foo is \(foo), bar is \(bar)") // "foo is 20.0, bar is 10.0"
 ```