Daniel Steinberg: The Open World of Swift 3

Transcript

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

205. None

206. The Open World of Swift 3 AppBuilders 2016 Daniel H

     Steinberg @dimsumthinking