Merge pull request #732 from cbess/master

[swift/en] - add more examples; update examples

swift.html.markdown

@@ -2,30 +2,51 @@
 language: swift
 contributors:
   - ["Grant Timmerman", "http://github.com/grant"]
+  - ["Christopher Bess", "http://github.com/cbess"]
 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.
 
+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/LandingPage/index.html), which has a complete tutorial on Swift.
 
 ```js
 //
-// Basics
+// MARK: Basics
 //
 
+// Xcode supports landmarks to annotate your code and lists them in the jump bar
+// MARK: Section mark
+// TODO: Do something soon
+// FIXME Fix this code
+
 println("Hello, world")
+
 var myVariable = 42
+let øπΩ = "value" // unicode variable names
 let myConstant = 3.1415926
+let convenience = "keyword" // contextual variable name
+let weak = "keyword"; let override = "another keyword" // statements can be separated by a semi-colon
+let `class` = "keyword" // backticks allow keywords to be used as variable names
 let explicitDouble: Double = 70
+let intValue = 0007 // 7
+let largeIntValue = 77_000 // 77000
 let label = "some text " + String(myVariable) // Casting
-let piText = "Pi = \(myConstant)"                 // String interpolation
+let piText = "Pi = \(myConstant), Pi 2 = \(myConstant * 2)" // String interpolation
 var optionalString: String? = "optional" // Can be nil
 optionalString = nil
 
+/*
+Comment here
+    /*
+        Nested comments are also supported
+    */
+*/
 
 //
-// Arrays and Dictionaries
+// MARK: Collections
 //
 
 // Array
@@ -43,7 +64,7 @@ let emptyDictionary = [String: Float]()
 
 
 //
-// Control Flow
+// MARK: Control Flow
 //
 
 // for loop (array)
@@ -57,6 +78,7 @@ for value in myArray {
 }
 
 // for loop (dictionary)
+var dict = ["one": 1, "two": 2]
 for (key, value) in dict {
     println("\(key): \(value)")
 }
@@ -93,13 +115,23 @@ default: // required (in order to cover all possible input)
 
 
 //
-// Functions
+// MARK: Functions
 //
 
 // Functions are a first-class type, meaning they can be nested
 // in functions and can be passed around
 
-// Function
+// Function with Swift header docs (format as reStructedText)
+/**
+    A greet operation
+
+    - A bullet in docs
+    - Another bullet in the docs
+
+    :param: name A name
+    :param: day A day
+    :returns: A string containing the name and day value.
+*/
 func greet(name: String, day: String) -> String {
     return "Hello \(name), today is \(day)."
 }
@@ -110,7 +142,7 @@ func getGasPrices() -> (Double, Double, Double) {
     return (3.59, 3.69, 3.79)
 }
 
-// Args
+// Variadic Args
 func setup(numbers: Int...) {}
 
 // Passing and returning functions
@@ -125,7 +157,7 @@ increment(7)
 
 
 //
-// Closures
+// MARK: Closures
 //
 var numbers = [1, 2, 6]
 
@@ -138,38 +170,90 @@ numbers.map({
     (number: Int) -> Int in
     let result = 3 * number
     return result
-  })
+})
 
 // When the type is known, like above, we can do this
 numbers = numbers.map({ number in 3 * number })
-//Or even this
+// Or even this
 //numbers = numbers.map({ $0 * 3 })
 
 print(numbers) // [3, 6, 18]
 
+// Trailing closure
+numbers = sorted(numbers) { $0 > $1 }
+
+print(numbers) // [18, 6, 3]
+
+// Super shorthand, since the < operator infers the types
+
+numbers = sorted(numbers, < )
+
+print(numbers) // [3, 6, 18]
 
 //
-// Classes
+// MARK: Structures
 //
 
+// Structures and classes have very similar capabilites
+struct NamesTable {
+    let names: [String]
+
+    // Custom subscript
+    subscript(index: Int) -> String {
+        return names[index]
+    }
+}
+
+// Structures have an auto-generated (implicit) designated initializer
+let namesTable = NamesTable(names: ["Me", "Them"])
+//let name = namesTable[2]
+//println("Name is \(name)") // Name is Them
+
+//
+// MARK: Classes
+//
+
+// Classes, structures and its members have three levels of access control
+// They are: internal (default), public, private
+
+public class Shape {
+    public func getArea() -> Int {
+        return 0;
+    }
+}
+
 // 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`
 
-// A simple class `Square` extends `Shape`
+internal class Rect: Shape {
-class Square: Shape {
     var sideLength: Int = 1
     
     // Custom getter and setter property
-  var perimeter: Int {
+    private var perimeter: Int {
         get {
             return 4 * sideLength
         }
         set {
+            // `newValue` is an implicit variable available to setters
             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`
+    var identifier: String = "defaultID" {
+        // the `willSet` arg will be the variable name for the new value
+        willSet(someIdentifier) {
+            print(someIdentifier)
+        }
+    }
+    
     init(sideLength: Int) {
         super.init()
         self.sideLength = sideLength
@@ -185,18 +269,27 @@ class Square: Shape {
         return sideLength * sideLength
     }
 }
-var mySquare = new Square(sideLength: 5)
+
+// A simple class `Square` extends `Rect`
+class Square: Rect {
+    convenience init() {
+        self.init(sideLength: 5)
+    }
+}
+
+var mySquare = Square()
 print(mySquare.getArea()) // 25
 mySquare.shrink()
 print(mySquare.sideLength) // 4
 
-// If you don't need a custom getter and setter,
+// compare instances, not the same as == which compares objects (equal to)
-// but still want to run code before and after getting or setting
+if mySquare === mySquare {
-// a property, you can use `willSet` and `didSet`
+    println("Yep, it's mySquare")
+}
 
 
 //
-// Enums
+// MARK: Enums
 //
 
 // Enums can optionally be of a specific type or on their own.
@@ -216,12 +309,101 @@ enum Suit {
 
 
 //
-// Other
+// MARK: Protocols
 //
 
-// `protocol`: Similar to Java interfaces.
+// `protocol`s can require that conforming types have specific
-// `extension`s: Add extra functionality to an already created type
+// instance properties, instance methods, type methods, 
+// operators, and subscripts.
+
+protocol ShapeGenerator {
+    var enabled: Bool { get set }
+    func buildShape() -> Shape
+}
+
+/*
+// Protocols declared with @objc allow optional functions,
+// which allow you to check for conformance
+@objc protocol TransformShape {
+    optional func reshaped()
+    optional func canReshape() -> Bool
+}
+
+class MyShape: Rect {
+    var delegate: TransformShape?
+
+    func grow() {
+        sideLength += 2
+
+        if let allow = self.delegate?.canReshape?() {
+            // test for delegate then for method
+            self.delegate?.reshaped?()
+        }
+    }
+}
+*/
+
+//
+// MARK: Other
+//
+
+// `extension`s: Add extra functionality to an already existing type
+
+// Square now "conforms" to the `Printable` protocol
+extension Square: Printable {
+    var description: String {
+        return "Area: \(self.getArea()) - ID: \(self.identifier)"
+    }
+}
+
+println("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(2)) // 42
+
 // Generics: Similar to Java. Use the `where` keyword to specify the
 //   requirements of the generics.
 
+func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? {
+    for (index, value) in enumerate(array) {
+        if value == valueToFind {
+            return index
+        }
+    }
+    return nil
+}
+let foundAtIndex = findIndex([1, 2, 3, 4], 3)
+println(foundAtIndex == 2) // true
+
+// Operators:
+// Custom operators can start with the characters:
+//      / = - + * % < > ! & | ^ . ~
+// or
+// Unicode math, symbol, arrow, dingbat, and line/box drawing characters.
+prefix operator !!! {}
+
+// A prefix operator that triples the side length when used
+prefix func !!! (inout shape: Square) -> Square {
+    shape.sideLength *= 3
+    return shape
+}
+
+// current value
+println(mySquare.sideLength) // 4
+
+// change side length using custom !!! operator, increases size by 3
+!!!mySquare
+println(mySquare.sideLength) // 12
+
 ```