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| -rw-r--r-- | swift.html.markdown | 95 |
1 files changed, 81 insertions, 14 deletions
diff --git a/swift.html.markdown b/swift.html.markdown index 600eedcf..f8fa31fe 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -8,6 +8,8 @@ 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 @@ -23,7 +25,7 @@ See also Apple's [getting started guide](https://developer.apple.com/library/pre println("Hello, world") var myVariable = 42 -//let fƒ∆ = "value" // unicode in variable names +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 @@ -39,7 +41,7 @@ optionalString = nil /* Comment here /* - Nested comment here + Nested comments are also supported */ */ @@ -119,7 +121,7 @@ default: // required (in order to cover all possible input) // Functions are a first-class type, meaning they can be nested // in functions and can be passed around -// Function with Swift function docs +// Function with Swift header docs (format as reStructedText) /** A greet operation @@ -189,11 +191,33 @@ numbers = sorted(numbers, < ) print(numbers) // [3, 6, 18] // +// 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 // -class Shape { - func getArea() -> Int { +// 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; } } @@ -203,23 +227,29 @@ class Shape { // structured object, you should use a `struct` // A simple class `Square` extends `Shape` -class Rect: Shape { +internal class Rect: 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) } @@ -254,7 +284,7 @@ print(mySquare.sideLength) // 4 // compare instances, not the same as == which compares objects (equal to) if mySquare === mySquare { - println("Yep its mySquare") + println("Yep, it's mySquare") } @@ -279,15 +309,47 @@ enum Suit { // -// MARK: Other +// MARK: Protocols // -// `protocol`: Similar to Java interfaces. +// `protocol`s can require that conforming types have specific +// 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)" @@ -321,7 +383,8 @@ func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? { } return nil } - +let foundAtIndex = findIndex([1, 2, 3, 4], 3) +println(foundAtIndex == 2) // true // Operators: // Custom operators can start with the characters: @@ -330,13 +393,17 @@ func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? { // Unicode math, symbol, arrow, dingbat, and line/box drawing characters. prefix operator !!! {} -// An operator that triples the side length when used +// A prefix operator that triples the side length when used prefix func !!! (inout shape: Square) -> Square { shape.sideLength *= 3 return shape } -let bigSquare = !!!mySquare -println(bigSquare.sideLength) +// current value +println(mySquare.sideLength) // 4 + +// change side length using custom !!! operator, increases size by 3 +!!!mySquare +println(mySquare.sideLength) // 12 ``` |