diff options
| -rw-r--r-- | swift.html.markdown | 81 |
1 files changed, 59 insertions, 22 deletions
diff --git a/swift.html.markdown b/swift.html.markdown index 77047355..ffe6cac2 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -13,6 +13,9 @@ The official [Swift Programming Language](https://itunes.apple.com/us/book/swift 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. ```swift +// import a module +import UIKit + // // MARK: Basics // @@ -26,7 +29,7 @@ println("Hello, world") var myVariable = 42 let øπΩ = "value" // unicode variable names -let myConstant = 3.1415926 +let π = 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 @@ -34,9 +37,24 @@ let explicitDouble: Double = 70 let intValue = 0007 // 7 let largeIntValue = 77_000 // 77000 let label = "some text " + String(myVariable) // Casting -let piText = "Pi = \(myConstant), Pi 2 = \(myConstant * 2)" // String interpolation -var optionalString: String? = "optional" // Can be nil -optionalString = nil +let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation +var someOptionalString: String? = "optional" // Can be nil + +if someOptionalString != nil { + // I am not nil + if someOptionalString!.hasPrefix("opt") { + println("has the prefix") + } + + let empty = someOptionalString?.isEmpty +} +someOptionalString = nil + +if let someStringConstant = someOptionalString { + // has Some value +} + +// AnyObject == id /* Comment here @@ -84,9 +102,10 @@ for (key, value) in dict { } // for loop (range) -for i in -1...1 { // [-1, 0, 1] +for i in -1...shoppingList.count { println(i) } +shoppingList[1...2] = ["steak", "peacons"] // use ..< to exclude the last number // while loop @@ -123,14 +142,14 @@ default: // required (in order to cover all possible input) // Function with Swift header docs (format as reStructedText) /** - A greet operation +A greet operation - - A bullet in docs - - Another bullet in the docs +- 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. +: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)." @@ -141,9 +160,16 @@ greet("Bob", "Tuesday") func getGasPrices() -> (Double, Double, Double) { return (3.59, 3.69, 3.79) } +let pricesTuple = getGasPrices() +let price = pricesTuple.2 // 3.79 +println("Gas price: \(price)") // Variadic Args -func setup(numbers: Int...) {} +func setup(numbers: Int...) { + // its an array + let number = numbers[0] + let argCount = numbers.count +} // Passing and returning functions func makeIncrementer() -> (Int -> Int) { @@ -155,6 +181,17 @@ func makeIncrementer() -> (Int -> Int) { var increment = makeIncrementer() increment(7) +// pass by ref +func swapTwoInts(inout a: Int, inout b: Int) { + let tempA = a + a = b + b = tempA +} +var someIntA = 7 +var someIntB = 3 +swapTwoInts(&someIntA, &someIntB) +println(someIntB) // 7 + // // MARK: Closures @@ -197,7 +234,7 @@ print(numbers) // [3, 6, 18] // Structures and classes have very similar capabilites struct NamesTable { let names: [String] - + // Custom subscript subscript(index: Int) -> String { return names[index] @@ -239,7 +276,7 @@ internal class Rect: Shape { sideLength = newValue / 4 } } - + // Lazily load a property // subShape remains nil (uninitialized) until getter called lazy var subShape = Rect(sideLength: 4) @@ -255,8 +292,9 @@ internal class Rect: Shape { } init(sideLength: Int) { - super.init() self.sideLength = sideLength + // always super.init last when init custom properties + super.init() } func shrink() { @@ -313,7 +351,7 @@ enum Suit { // // `protocol`s can require that conforming types have specific -// instance properties, instance methods, type methods, +// instance properties, instance methods, type methods, // operators, and subscripts. protocol ShapeGenerator { @@ -321,7 +359,6 @@ protocol ShapeGenerator { func buildShape() -> Shape } -/* // Protocols declared with @objc allow optional functions, // which allow you to check for conformance @objc protocol TransformShape { @@ -331,17 +368,17 @@ protocol ShapeGenerator { 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 @@ -363,7 +400,7 @@ extension Int { var customProperty: String { return "This is \(self)" } - + func multiplyBy(num: Int) -> Int { return num * self } @@ -372,7 +409,7 @@ extension Int { println(7.customProperty) // "This is 7" println(14.multiplyBy(2)) // 42 -// Generics: Similar to Java. Use the `where` keyword to specify the +// Generics: Similar to Java and C#. Use the `where` keyword to specify the // requirements of the generics. func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? { |