Daniel Steinberg: The Open World of Swift 3

1. The Open World of Swift 3 AppBuilders 2016 Daniel H Steinberg @dimsumthinking
2. Swift
3. Open
4. Open?
5. Open!
6. Future
7. Future?
8. Future!
9. What can we see?
10. 0025 - Scoped Access Levels
11. public internal private
12. public internal private
13. public internal private
14. public internal private
15. public internal fileprivate
16. public internal fileprivate private
17. class MyClass { private var myProperty = "Hello" private func myPrivateMethod() { print(myProperty) } fileprivate func myFilePrivateMethod(numberOfTimes times: Int) { for _ in 1 ... times { myPrivateMethod() } } } extension MyClass { func myExtensionMethod(numberOfTimes times: Int) { myInternalMethod(numberOfTimes: times) } }
18. class MyClass { private var myProperty = "Hello" private func myPrivateMethod() { print(myProperty) } fileprivate func myFilePrivateMethod(numberOfTimes times: Int) { for _ in 1 ... times { myPrivateMethod() } } } extension MyClass { func myExtensionMethod(numberOfTimes times: Int) { myInternalMethod(numberOfTimes: times) } }
19. class MyClass { private var myProperty = "Hello" private func myPrivateMethod() { print(myProperty) } fileprivate func myFilePrivateMethod(numberOfTimes times: Int) { for _ in 1 ... times { myPrivateMethod() } } } extension MyClass { func myExtensionMethod(numberOfTimes times: Int) { myInternalMethod(numberOfTimes: times) } }
20. class MyClass { private var myProperty = "Hello" private func myPrivateMethod() { print(myProperty) } fileprivate func myFilePrivateMethod(numberOfTimes times: Int) { for _ in 1 ... times { myPrivateMethod() } } } extension MyClass { func myExtensionMethod(numberOfTimes times: Int) { myInternalMethod(numberOfTimes: times) } }
21. class MyClass { private var myProperty = "Hello" private func myPrivateMethod() { print(myProperty) } fileprivate func myFilePrivateMethod(numberOfTimes times: Int) { for _ in 1 ... times { myPrivateMethod() } } } extension MyClass { func myExtensionMethod(numberOfTimes times: Int) { myInternalMethod(numberOfTimes: times) } }
22. public internal fileprivate private
23. 0004 - Remove ++ and —
24. while count < upperLimit { print( myArray[count++]) }
25. while count < upperLimit { print( myArray[count++]) }
26. while count < upperLimit { print( myArray[count]) count += 1 }
27. 0007 - Remove C Style for loops with conditions and incrementors
28. for (int i = 0; i < array.count; i++)
29. for (int i = 0; i < array.count; i++)
30. 0053 - Remove explicit use of let from Function Parameters
31. func double(input: Int) -> Int { // ... }
32. func double(let input: Int) -> Int { // ... }
33. func double(let input: Int) -> Int { // ... }
34. 0003 - Remove var from Function Parameters
35. func double(input: Int) -> Int { input = input * 2 return input }
36. func double(var input: Int) -> Int { input = input * 2 return input }
37. func double(var input: Int) -> Int { input = input * 2 return input }
38. func double(input: Int) -> Int { var localInput = input localInput = localInput * 2 return localInput }
39. func double(input: Int) -> Int { var localInput = input localInput = localInput * 2 return localInput }
40. func double(input: Int) -> Int { var input = input input = input * 2 return input } Name Shadowing
41. func double(input: Int) -> Int { var input = input input = input * 2 return input }
42. 0031 - Adjusting inout Declarations for Type Decoration
43. func double(input: Int) { input = input * 2 }
44. func double(inout input: Int) { input = input * 2 }
45. func double(inout input: Int) { input = input * 2 }
46. func double(input: inout Int) { input = input * 2 }
47. 0053 - Limiting inout capture to @noescape context
48. func escape(f: () -> ()) {} func example(inout x: Int) { escape { _ = x } }
49. func escape(f: () -> ()) {} func example(inout x: Int) { escape { _ = x } }
50. func escape(f: () -> ()) {} func example(inout x: Int) { escape { _ = x } }
51. func escape(f: () -> ()) {} func example(inout x: Int) { escape { _ = x } }
52. func escape(f: () -> ()) {} func example(inout x: Int) { escape { _ = x } }
53. func escape(f: () -> ()) {} func example(inout x: Int) { escape { _ = x } }
54. func escape(f: () -> ()) {} func example(inout x: Int) { escape { _ = x } }
55. func noEscape(@noescape f: () -> ()) {} func example(inout x: Int) { noEscape { _ = x } }
56. func noEscape(@noescape f: () -> ()) {} func example(inout x: Int) { noEscape { _ = x } } safe because @noescape => closure can't be called after function returns
57. func escape(f: () -> ()) {} func example(inout x: Int) { escape { _ = x } }
58. func escape(f: () -> ()) {} func example(inout x: Int) { escape {[x] in _ = x } }
59. func escape(f: () -> ()) {} func example(inout x: Int) { escape {[x] in _ = x } } [x] is a capture list a constant is initialized to have the value of x
60. 0049 - Move @noescape and @autoclosure to be type attributes
61. func noEscape(@noescape f: () -> ()) {}
62. func noEscape(f: @noescape () -> ()) {}
63. func noEscape(f: @autoclosure () -> ()) {}
64. 0002 - Remove currying func declaration syntax
65. 0002 - Remove currying func declaration syntax
66. 0002 - Remove currying func declaration syntax
67. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
68. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
69. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
70. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
71. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8) 7 * y
72. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8) 7 * 8
73. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
74. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
75. func curried(x: Int)(y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
76. func curried(x: Int) -> (y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
77. func curried(x: Int) -> (y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
78. func curried(x: Int) -> (y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
79. func curried(x: Int) -> (y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
80. func curried(x: Int) -> (y: Int) -> Int { return {(y: Int) -> Int in return x * y } } curried(7)(8)
81. Testing
82. Playgrounds
83. Package Manager
84. Objective-C
85. 0022 - Referencing the Obj-C selector of a method
86. class MyClass : NSObject { func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: "callbackMethod", name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
87. class MyClass : NSObject { func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: "callbackMethod", name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
88. class MyClass : NSObject { func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: "callbackMethod", name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
89. class MyClass : NSObject { func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: "callbackMethod", name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
90. class MyClass : NSObject { func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: "callbackMethod", name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
91. class MyClass : NSObject { func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: "callbackMethod", name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
92. class MyClass : NSObject { func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: #selector(callbackMethod), name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
93. class MyClass : NSObject { func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: #selector(MyClass.callbackMethod), name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
94. class MyClass : NSObject { func callbackMethod(){} func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: #selector(MyClass.callbackMethod), name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
95. class MyClass : NSObject { func callbackMethod(){} func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: #selector(MyClass.callbackMethod), name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
96. class MyClass : NSObject { func callbackMethod(){} func callbackMethod(with notification: NSNotification){} func setNotification() { let center = NSNotificationCenter.defaultCenter() center .addObserver(self, selector: #selector(MyClass.callbackMethod(with:)), name: NSApplicationWillResignActiveNotification, object: NSApplication.sharedApplication()) } }
97. 0033 - Import Obj-C constants as Swift types
98. HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyMassIndex; HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyFatPercentage; HK_EXTERN NSString * const HKQuantityTypeIdentifierHeight; HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyMass; HK_EXTERN NSString * const HKQuantityTypeIdentifierLeanBodyMass;
99. HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyMassIndex; HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyFatPercentage; HK_EXTERN NSString * const HKQuantityTypeIdentifierHeight; HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyMass; HK_EXTERN NSString * const HKQuantityTypeIdentifierLeanBodyMass;
100. enum HKQuantityTypeIdentifier : String { case BodyMassIndex case BodyFatPercentage case Height case BodyMass case LeanBodyMass }
101. enum HKQuantityTypeIdentifier : String { case BodyMassIndex case BodyFatPercentage case Height case BodyMass case LeanBodyMass }
102. HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyMassIndex; HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyFatPercentage; HK_EXTERN NSString * const HKQuantityTypeIdentifierHeight; HK_EXTERN NSString * const HKQuantityTypeIdentifierBodyMass; HK_EXTERN NSString * const HKQuantityTypeIdentifierLeanBodyMass;
103. enum HKQuantityTypeIdentifier : String { case BodyMassIndex case BodyFatPercentage case Height case BodyMass case LeanBodyMass }
104. enum HKQuantityTypeIdentifier : String { case BodyMassIndex case BodyFatPercentage case Height case BodyMass case LeanBodyMass }
105. 0005 - Better translation of Obj-C APIs into Swift
106. let color = NSColor.blueColor()
107. let color = NSColor.blueColor()
108. let color = NSColor.blueColor() Prune redundant type names
109. let color = NSColor.blue()
110. rootViewController .presentViewController(alert, animated: true, completion: nil)
111. rootViewController .presentViewController(alert, animated: true, completion: nil) Add default arguments
112. rootViewController .presentViewController(alert, animated: true, completion: nil) Nullable trailing closures default = nil
113. rootViewController .presentViewController(alert, animated: true)
114. rootViewController .presentViewController(alert, animated: true) Shouldn't animated default = true
115. rootViewController.presentViewController(alert)
116. rootViewController.presentViewController(alert) Prune redundant type names
117. rootViewController.present(alert)
118. var empty: Bool
119. var empty: Bool Prepend "is" to Bools
120. var isEmpty: Bool
121. addLineToPoint(myPoint)
122. addLineToPoint(myPoint) func addLineToPoint(_: CGPoint)
123. addLineToPoint(myPoint) func addLineToPoint(_: CGPoint) Add first argument labels
124. addLineToPoint(myPoint) func addLineToPoint(_: CGPoint) Add first argument labels
125. addLine(to: myPoint) func addLine(to point: CGPoint) Add first argument labels
126. addLine(to: myPoint) func addLine(to point: CGPoint) Add first argument labels
127. Add first argument labels
128. Add first argument labels
129. var URLHandler
130. var URLHandler Lower case imported types
131. var urlHandler Lower case imported types
132. enum Currency { case Dollars case Euros case Pounds case Yen } Lower case imported types
133. enum Currency { case Dollars case Euros case Pounds case Yen } Lower case imported types
134. enum Currency { case dollars case euros case pounds case yen } Lower case imported types
135. 0036 - Requiring Leading Dot Prefixes for Enum Instance Member Implementations
136. enum Currency { case dollars case euros case pounds case yen var symbol: String { switch self { case dollars: return "$" default: return "I don't know" } } }
137. enum Currency { case dollars case euros case pounds case yen var symbol: String { switch self { case .dollars: return "$" default: return "I don't know" } } }
138. enum Currency { case dollars case euros case pounds case yen var symbol: String { switch self { case dollars: return "$" default: return "I don't know" } } }
139. enum Currency { case dollars case euros case pounds case yen var symbol: String { switch self { case .dollars: return "$" default: return "I don't know" } } }
140. enum Currency { case dollars case euros case pounds case yen var symbol: String { switch self { case .dollars: return "$" default: return "I don't know" } } }
141. 0043 - Declare variables in 'case' labels with multiple patterns
142. enum MyEnum { case case1(Int,Float) case case2(Float,Int) } switch value { case let .case1(x, 2), let .case2(2, x): print(x) case .case1, .case2: break }
143. enum MyEnum { case case1(Int,Float) case case2(Float,Int) } switch value { case let .case1(x, 2), let .case2(2, x): print(x) case .case1, .case2: break }
144. enum MyEnum { case case1(Int,Float) case case2(Float,Int) } switch value { case let .case1(x, 2), let .case2(2, x): print(x) case .case1, .case2: break }
145. enum MyEnum { case case1(Int,Float) case case2(Float,Int) } switch value { case let .case1(x, 2), let .case2(2, x): print(x) case .case1, .case2: break }
146. enum MyEnum { case case1(Int,Float) case case2(Float,Int) } switch value { case let .case1(x, 2), let .case2(2, x): print(x) case .case1, .case2: break }
147. enum MyEnum { case case1(Int,Float) case case2(Float,Int) } switch value { case let .case1(x, 2), let .case2(2, x): print(x) case .case1, .case2: break }
148. enum MyEnum { case case1(Int,Float) case case2(Float,Int) } switch value { case let .case1(x, 2), let .case2(2, x): print(x) case .case1, .case2: break }
149. 0001 - Allow (most) keywords as argument labels
150. calculateRevenue(for sales: Int, in currency: Currency)
151. calculateRevenue(for sales: Int, in currency: Currency)
152. calculateRevenue(for numberOfCopies, in .dollars)
153. 0009 - Require self for accessing instance members
154. struct Friend { let name: String let location: String func nameBadge() { print("I'm", name, "from", location) } }
155. struct Friend { let name: String let location: String func nameBadge() { print("I'm", name, "from", location) } }
156. struct Friend { let name: String let location: String func nameBadge() { print("I'm", name, "from", location) } }
157. struct Friend { let name: String let location: String func nameBadge() { print("I'm", self.name, "from", self.location) } }
158. struct Friend { let name: String let location: String func nameBadge() { print("I'm", self.name, "from", self.location) } } Require self for accessing instance members REJECTED
159. 0011 - Replace typealias keyword with associatedtype for associated type declarations
160. 0011 - Replace typealias keyword with associatedtype for associated type declarations
161. protocol Prot { typealias Container : SequenceType } extension Prot { typealias Element = Container.Generator.Element }
162. protocol Prot { typealias Container : SequenceType } extension Prot { typealias Element = Container.Generator.Element }
163. protocol Prot { associatedtype Container : SequenceType } extension Prot { typealias Element = Container.Generator.Element }
164. 0046 Establish consistent label behavior across all parameters including first labels
165. func increase(ourNumber: Int, delta: Int) -> Int { } increase(6, delta: 3)
166. func increase(ourNumber: Int, delta: Int) -> Int { } increase(6, delta: 3)
167. func increase(ourNumber: Int, delta: Int) -> Int { } increase(6, delta: 3)
168. func increase(ourNumber: Int, delta: Int) -> Int { } increase(6, delta: 3)
169. func increase(ourNumber: Int, delta: Int) -> Int { } increase(ourNumber: 6, delta: 3)
170. func increase(_ ourNumber: Int, delta: Int) -> Int { } increase(6, delta: 3)
171. 0023 - Swift API Guidelines
172. Swift API Design Guidelines
173. myArray.sort()
174. sort() sorted()
175. sortInPlace() sort()
176. sort() sorted()
177. sort() sorted() Name functions and methods according to their side-effects
178. x.distance(to: y) i.successor() Those without side-effects should read as noun phrases
179. x.sort() x.append(y) Those with side-effects should read as imperative noun phrases
180. sort() sorted()/sorting() Use the “ed/ing” rule to name the nonmutating counterpart of a mutating method
181. Prefer methods to free functions
182. Prefer methods to free functions Protocol Extensions in Swift 2
183. Prefer methods to free functions Protocol Extensions in Swift 2 Except …
184. min(x, y, z) When there's no obvious self
185. print(x) When the function is an unconstrained generic
186. sin(x) When the function is part of the established domain notation
187. Methods can share a base name
188. Methods can share a base name Good when they do analogous things
189. Methods can share a base name Not good (tableView!) when they don't
190. Choose good parameter names
191. func move(from startingIndex: Int, to endingIndex: Int) Choose good parameter names
192. Take advantage of default values
193. Take advantage of default values func hello(name: String = "World")
194. Take advantage of default values init(name: String, hometown: String? = nil)
195. Prefer to locate parameters with defaults at the end init(name: String, hometown: String? = nil)
196. External Argument Labels func move(from startingIndex: Int, to endingIndex: Int)
197. move(from: here to: there)
198. Argument Labels Exceptions
199. min(number1, number2) Omit labels when arguments can't be distinguished
200. Double(someInt) Omit labels in full width inits
201. Double(_ anInt: someInt) Omit labels in full width inits
202. func move(from startingIndex: Int, to endingIndex: Int) When the preposition applies to the whole
203. func moveTo(x: Int, y: Int) When the preposition applies to the whole
204. x.removeBoxes(having Length: 12) When the preposition applies to the whole
206. The Open World of Swift 3 AppBuilders 2016 Daniel H Steinberg @dimsumthinking