From d540d1c67bb123f8e7dc3233be957e29d8983e4b Mon Sep 17 00:00:00 2001 From: Clayton Walker Date: Tue, 6 Oct 2015 22:25:38 -0400 Subject: Original link directs to page that can't be found. Changed to represent new location of the Apple Developer tutorial on swift. --- swift.html.markdown | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'swift.html.markdown') diff --git a/swift.html.markdown b/swift.html.markdown index 509c9d2f..86a0b89a 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -12,7 +12,7 @@ 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 -- cgit v1.2.3 From 5dac348b72000dedc2e8a35f1ccaea55a7f408f7 Mon Sep 17 00:00:00 2001 From: Clayton Walker Date: Tue, 6 Oct 2015 23:00:11 -0400 Subject: Forgot to add myself as a contributor from swift-1 pull request. --- swift.html.markdown | 1 + 1 file changed, 1 insertion(+) (limited to 'swift.html.markdown') diff --git a/swift.html.markdown b/swift.html.markdown index 509c9d2f..23ebcfc5 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -5,6 +5,7 @@ contributors: - ["Christopher Bess", "http://github.com/cbess"] - ["Joey Huang", "http://github.com/kamidox"] - ["Anthony Nguyen", "http://github.com/anthonyn60"] + - ["Clayton Walker", "https://github.com/cwalk"] filename: learnswift.swift --- -- cgit v1.2.3 From ad16a31c0751f244a46cadbfb3540943af73349d Mon Sep 17 00:00:00 2001 From: Clayton Walker Date: Tue, 6 Oct 2015 23:36:32 -0400 Subject: Added clearer description of Optionals and Unwrapping. Minor typo changes as well. --- swift.html.markdown | 43 +++++++++++++++++++++++++------------------ 1 file changed, 25 insertions(+), 18 deletions(-) (limited to 'swift.html.markdown') diff --git a/swift.html.markdown b/swift.html.markdown index 23ebcfc5..46e5e6d4 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -58,8 +58,9 @@ let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation 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. @@ -75,11 +76,17 @@ if someOptionalString != nil { if someOptionalString!.hasPrefix("opt") { print("has the prefix") } - + let empty = someOptionalString?.isEmpty } someOptionalString = nil +/* + To get the underlying type from an optional, you unwrap it using the + force unwrap operator (!). Only use the unwrap operator if you're sure + the underlying value isn't nil. +*/ + // implicitly unwrapped optional var unwrappedString: String! = "Value is expected." // same as above, but ! is a postfix operator (more syntax candy) @@ -94,13 +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 */ @@ -296,10 +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] @@ -330,7 +337,7 @@ public class Shape { internal class Rect: Shape { var sideLength: Int = 1 - + // Custom getter and setter property private var perimeter: Int { get { @@ -341,11 +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` @@ -355,19 +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 } @@ -399,13 +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 } @@ -459,7 +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): @@ -498,7 +505,7 @@ protocol ShapeGenerator { class MyShape: Rect { var delegate: TransformShape? - + func grow() { sideLength += 2 @@ -533,7 +540,7 @@ extension Int { var customProperty: String { return "This is \(self)" } - + func multiplyBy(num: Int) -> Int { return num * self } -- cgit v1.2.3 From 960ee4a1856db8eadb96277bb2422edfa8f2a81c Mon Sep 17 00:00:00 2001 From: Gabriel Halley Date: Wed, 7 Oct 2015 23:11:24 -0400 Subject: removing whitespace all over --- swift.html.markdown | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) (limited to 'swift.html.markdown') diff --git a/swift.html.markdown b/swift.html.markdown index 86a0b89a..a40e86c8 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -3,7 +3,7 @@ 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"] filename: learnswift.swift --- @@ -74,7 +74,7 @@ if someOptionalString != nil { if someOptionalString!.hasPrefix("opt") { print("has the prefix") } - + let empty = someOptionalString?.isEmpty } someOptionalString = nil @@ -99,7 +99,7 @@ anyObjectVar = "Changed value to a string, not good practice, but possible." /* Comment here - + /* Nested comments are also supported */ @@ -298,7 +298,7 @@ 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] @@ -329,7 +329,7 @@ public class Shape { internal class Rect: Shape { var sideLength: Int = 1 - + // Custom getter and setter property private var perimeter: Int { get { @@ -340,11 +340,11 @@ 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` @@ -354,19 +354,19 @@ 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 } @@ -398,13 +398,13 @@ 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 } @@ -458,7 +458,7 @@ enum Furniture { case Desk(height: Int) // Associate with String and Int case Chair(String, Int) - + func description() -> String { switch self { case .Desk(let height): @@ -497,7 +497,7 @@ protocol ShapeGenerator { class MyShape: Rect { var delegate: TransformShape? - + func grow() { sideLength += 2 @@ -532,7 +532,7 @@ extension Int { var customProperty: String { return "This is \(self)" } - + func multiplyBy(num: Int) -> Int { return num * self } -- cgit v1.2.3 From 707c8db171cb5239682332f14fd2098901741c63 Mon Sep 17 00:00:00 2001 From: Valentine Silvansky Date: Thu, 8 Oct 2015 10:00:13 +0300 Subject: Add generics operator in Swift --- swift.html.markdown | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'swift.html.markdown') diff --git a/swift.html.markdown b/swift.html.markdown index a40e86c8..75535e43 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -574,4 +574,18 @@ print(mySquare.sideLength) // 4 // change side length using custom !!! operator, increases size by 3 !!!mySquare print(mySquare.sideLength) // 12 + +// Operators can also be generics +infix operator <-> {} +func <-> (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" ``` -- cgit v1.2.3 From b4860de42f2bbf0ab97ef28085eb40accb030657 Mon Sep 17 00:00:00 2001 From: Clayton Walker Date: Thu, 8 Oct 2015 23:27:19 -0400 Subject: Suggested changes --- swift.html.markdown | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'swift.html.markdown') diff --git a/swift.html.markdown b/swift.html.markdown index 46e5e6d4..9f0019d8 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -58,8 +58,8 @@ let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation print("Build value: \(buildValue)") // Build value: 7 /* - Optionals are a Swift language feature that either contains a value, - or contains nil (no value) to indicate that a value is missing. + 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 @@ -82,9 +82,9 @@ if someOptionalString != nil { someOptionalString = nil /* - To get the underlying type from an optional, you unwrap it using the - force unwrap operator (!). Only use the unwrap operator if you're sure - the underlying value isn't 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 -- cgit v1.2.3