Swift Smart KeyPath

Transcript

1. Swift Smart KeyPath
 Better Key-Value Coding for Swift iOS@Taipei 艾倫倫 Ni
2. What is Smart KeyPath?
3. What is Smart KeyPath? \UIView.frame
4. \UIView.frame
5. \UIView.frame BackSlash
6. \UIView.frame Dot
7. \UIView.frame BaseType
8. \UIView.frame BaseType PropertyName
9. Proposal: SE-0161 Implemented (Swift 4) Defer way to get / set property With type information (#keyPath( ) only return ‘Any’)
 Applicable to any type (#keyPath( ) only applicable to NSObjects) \UIView.frame
10. Proposal: SE-0161 Implemented (Swift 4) Defer way to get / set property With type information (#keyPath( ) only return ‘Any’)
 Applicable to any type (#keyPath( ) only applicable to NSObjects) let keyPath = \UIView.frame view[keyPath: keyPath] \UIView.frame
11. Proposal: SE-0161 Implemented (Swift 4) Defer way to get / set property With type information (#keyPath( ) only return ‘Any’)
 Applicable to any type (#keyPath( ) only applicable to NSObjects) let keyPath = \UIView.frame view[keyPath: keyPath] \UIView.frame
12. Proposal: SE-0161 Implemented (Swift 4) Defer way to get / set property With type information (#keyPath( ) only return ‘Any’)
 Applicable to any type (#keyPath( ) only applicable to NSObjects) let keyPath = \UIView.frame view[keyPath: keyPath] let frame = view[keyPath: path] \UIView.frame
13. Proposal: SE-0161 Implemented (Swift 4) Defer way to get / set property With type information (#keyPath( ) only return ‘Any’)
 Applicable to any type (#keyPath( ) only applicable to NSObjects) let keyPath = \UIView.frame view[keyPath: keyPath] let frame = view[keyPath: path] \UIView.frame //frame: CGRect
14. Proposal: SE-0161 Implemented (Swift 4) Defer way to get / set property With type information (#keyPath( ) only return ‘Any’)
 Applicable to any type (#keyPath( ) only applicable to NSObjects) let keyPath = \UIView.frame view[keyPath: keyPath] let frame = view[keyPath: path] struct User { var id: Int } \UIView.frame //frame: CGRect
15. Proposal: SE-0161 Implemented (Swift 4) Defer way to get / set property With type information (#keyPath( ) only return ‘Any’)
 Applicable to any type (#keyPath( ) only applicable to NSObjects) let keyPath = \UIView.frame view[keyPath: keyPath] let frame = view[keyPath: path] struct User { var id: Int } \User.id \UIView.frame //frame: CGRect
16. KeyPath<Root, Value> \UIView.frame <UIView, CGRect> \UIView.frame.size <UIView, CGSize>
17. AnyKeyPath PartialKeyPath<Root> KeyPath<Root, Value> WritableKeyPath<Root, Value> ReferenceWritableKeyPath<Root, Value>
18. KeyPath<Root, Value> WritableKeyPath<Root, Value> ReferenceWritableKeyPath<Root, Value>
19. KeyPath<Root, Value> WritableKeyPath<Root, Value> ReferenceWritableKeyPath<Root, Value> read only
20. KeyPath<Root, Value> WritableKeyPath<Root, Value> ReferenceWritableKeyPath<Root, Value> read only read / write (variable)
21. KeyPath<Root, Value> WritableKeyPath<Root, Value> ReferenceWritableKeyPath<Root, Value> read only read / write (variable) read / write (variable/constant) Class only
22. \UIView.frame.size \UIView.frame.width
23. \UIView.frame.size \UIView.frame.width -> ReferenceWritableKeyPath
24. \UIView.frame.size \UIView.frame.width -> ReferenceWritableKeyPath -> KeyPath
25. \UIView.frame.size \UIView.frame.width struct User { var id: Int } -> ReferenceWritableKeyPath -> KeyPath
26. \UIView.frame.size \UIView.frame.width struct User { var id: Int } -> ReferenceWritableKeyPath -> KeyPath -> WritableKeyPath \User.id
27. struct Ticket { var price: Int } let tickets = [Int](0...5) .compactMap{ Ticket(price: $0) } // [ {price 0}, ..., {price 5} ]
28. extension Array { } func sum<T: Numeric> (of keyPath: KeyPath<Element, T>) -> T { return reduce(0, {$0 += $1[keyPath: keyPath]} ) }
29. extension Array { } func sum<T: Numeric> (of keyPath: KeyPath<Element, T>) -> T { return reduce(0, {$0 += $1[keyPath: keyPath]} ) } tickets.sum(of: \.price) // 15
30. extension Array { } func sorted<T: Comparable> (_ keyPath: KeyPath<Element, T>, by comparation: (T, T) -> Bool) -> [Element] { return sorted(by: { comparation($0[keyPath: keyPath], $1[keyPath: keyPath]) }) }
31. extension Array { } func sorted<T: Comparable> (_ keyPath: KeyPath<Element, T>, by comparation: (T, T) -> Bool) -> [Element] { return sorted(by: { comparation($0[keyPath: keyPath], $1[keyPath: keyPath]) }) } tickets.sorted(\.price, by: >) // {price 5}, ..., {price 1}
32. extension Array { } func calculate<T: Comparable> (_ keyPath: KeyPath<Element, T>, with operation: (T, T) -> T) -> T? { guard !isEmpty else { return nil } var copy = self let initValue = copy.removeFirst()[keyPath: keyPath] return copy.reduce(initValue, { operation($0, $1[keyPath: keyPath]) }) }
33. extension Array { } func calculate<T: Comparable> (_ keyPath: KeyPath<Element, T>, with operation: (T, T) -> T) -> T? { guard !isEmpty else { return nil } var copy = self let initValue = copy.removeFirst()[keyPath: keyPath] return copy.reduce(initValue, { operation($0, $1[keyPath: keyPath]) }) } tickets.calculate(\.price, with: +) // 15
34. tickets.sorted(\.price, by: >) tickets.calculate(\.price, with: +) tickets.sum(of: \.price)
35. tickets.sorted(\.price, by: >) tickets.calculate(\.price, with: +) tickets.sum(of: \.price) tickets.reduce(0, { $0 + $1.price })
36. Property Validation
37. let pswdField: UITextField = .init() pswdField.text = "1234" pswdField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 6 }) .check(\.text, with: { $0 != "123456" }) .validate() // false
38. protocol Validation: NSObject { }
39. extension Validation { var currentResult: Bool? { get { return objc_getAssociatedObject(self, &AssociaKeys.currResult) as? Bool } set { objc_setAssociatedObject(self, &AssociaKeys.currResult, newValue, .OBJC_ASSOCIATION_RETAIN)} } } extension NSObject: Validation { fileprivate struct AssociaKeys { static var currResult = "currResult" } } protocol Validation: NSObject { }
40. func check<T>(_ target: KeyPath<Self, T>, with condition: (T) -> Bool) -> Self { if currentResult == false { return self } else { self.currentResult = condition(self[keyPath: target]) return self } } protocol Validation: NSObject { } extension Validation { }
41. func check<T>(_ target: KeyPath<Self, T>, with condition: (T) -> Bool) -> Self { if currentResult == false { return self } else { self.currentResult = condition(self[keyPath: target]) return self } } func validate() -> Bool { if let validate = currentResult { currentResult = nil print(validate) return validate } else { return true } } protocol Validation: NSObject { } extension Validation { }
42. let pswdField: UITextField = .init() pswdField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 6 }) .check(\.text, with: { $0 != "123456" }) .validate()
43. let pswdField: UITextField = .init() pswdField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 6 }) .check(\.text, with: { $0 != "123456" }) .check(\.frame.size.width, with: { $0 >= 100 }) .validate()
44. Property Validation
45. Property Validation Second Case
46. let pswdField: UITextField = .init() pswdField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 8 }) .check(\.text, with: { $0 != "123456" }) // do something else ... pswdField.text = "123456" // do something else again … pswdField.validate() // false
47. struct ValidationStash<ClassType, T> { var condition: (T) -> Bool var keypath: KeyPath<ClassType, T> } protocol Validation: class { associatedtype ClassType associatedtype ValueType var stashes: [ValidationStash <ClassType, ValueType?>]? { set get } } extension Validation { func check( _ target: KeyPath<ClassType, ValueType?>, with condition: @escaping (ValueType? ) -> Bool) -> Self { //... } func validate() -> Bool { //... } }
48. struct ValidationStash<ClassType, T> { var condition: (T) -> Bool var keypath: KeyPath<ClassType, T> } protocol Validation: class { associatedtype ClassType associatedtype ValueType var stashes: [ValidationStash <ClassType, ValueType?>]? { set get } } extension Validation { func check( _ target: KeyPath<ClassType, ValueType?>, with condition: @escaping (ValueType? ) -> Bool) -> Self { //... } func validate() -> Bool { //... } }
49. func check( _ target: KeyPath<ClassType, ValueType?>, with condition: @escaping (ValueType? ) -> Bool) -> Self { let model = ValidationStash(condition: condition, keypath: target) if var array = stashes { array.append(model) stashes = array } else { stashes = [model] } return self }
50. func validate() -> Bool { for stash in stashes ?? [] { guard let self = self as? ClassType else { continue } let target = self[keyPath: stash.keypath] let result = stash.condition(target) if result == false { return result } } return true }
51. extension UITextField: Validation { typealias ClassType = UITextField typealias ValueType = String var stashes: [ValidationStash<ClassType, ValueType?>]? { get { return objc_getAssociatedObject(self, &AssociatedKeys.array) as? [ValidationStash] } set { objc_setAssociatedObject(self, &AssociatedKeys.array, newValue, .OBJC_ASSOCIATION_RETAIN)} } fileprivate struct AssociatedKeys { static var array = “AssociatedKeys_array" } }
52. userField.validate() // false pswdField.validate() // true let userField: UITextField = .init() userField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 8 }) .check(\.text, with: { $0 != "123456" }) let pswdField: UITextField = .init() pswdField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 6 }) .check(\.text, with: { $0 != "123456" }) userField.text = "123456" pswdField.text = "demo123456"
53. userField.validate() // false pswdField.validate() // true let userField: UITextField = .init() userField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 8 }) .check(\.text, with: { $0 != "123456" }) let pswdField: UITextField = .init() pswdField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 6 }) .check(\.text, with: { $0 != "123456" }) userField.text = "123456" pswdField.text = "demo123456"
54. userField.validate() // false pswdField.validate() // true let userField: UITextField = .init() userField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 8 }) .check(\.text, with: { $0 != "123456" }) let pswdField: UITextField = .init() pswdField .check(\.text, with: { $0?.isEmpty == false }) .check(\.text, with: { $0?.count ?? 0 >= 6 }) .check(\.text, with: { $0 != "123456" }) userField.text = "123456" pswdField.text = "demo123456"
55. Fluent AutoLayout
56. var label = UILabel() .set(\.text, to: "Hello World.") .set(\.font, to: .systemFont(ofSize: 14)) .set(\.lineBreakMode, to: .byWordWrapping) .set(\.numberOfLines, to: 0) .set(\.textColor, to: .darkGray) func set<T>(_ keyPath: ReferenceWritableKeyPath<Self, T>, to value: T) -> Self { self[keyPath: keyPath] = value return self } Reference: http://www.swifttube.co/video/the-underestimated-power-of- keypaths
57. var label = UILabel() .set(\.text, to: "Hello World.") .set(\.font, to: .systemFont(ofSize: 14)) .set(\.lineBreakMode, to: .byWordWrapping) .set(\.numberOfLines, to: 0) .set(\.textColor, to: .darkGray) func set<T>(_ keyPath: ReferenceWritableKeyPath<Self, T>, to value: T) -> Self { self[keyPath: keyPath] = value return self } Reference: http://www.swifttube.co/video/the-underestimated-power-of- keypaths Easy to implement Fluent Interface!
58. var label = UILabel() .set(\.text, to: "Hello World.") .set(\.font, to: .systemFont(ofSize: 14)) .set(\.lineBreakMode, to: .byWordWrapping) .set(\.numberOfLines, to: 0) .set(\.textColor, to: .darkGray) func set<T>(_ keyPath: ReferenceWritableKeyPath<Self, T>, to value: T) -> Self { self[keyPath: keyPath] = value return self } Reference: http://www.swifttube.co/video/the-underestimated-power-of- keypaths Easy to implement Fluent Interface! -> Self -> Self -> Self -> Self -> Self
59. descLabel .translatesAutoresizingMaskIntoConstraints = false let constraints = [ descLabel.widthAnchor .constraint(equalTo: view.widthAnchor, multiplier: 0.9, constant: 10), descLabel.heightAnchor .constraint(greaterThanOrEqualTo: view.heightAnchor), descLabel.centerYAnchor .constraint(equalTo: view.centerYAnchor, constant: 0), descLabel.centerXAnchor .constraint(equalTo: view.centerXAnchor, constant: 0) ] NSLayoutConstraint.activate(constraints)
60. nameLabel.translatesAutoresizingMaskIntoConstraints = false nameLabel.widthAnchor.constraint(equalTo: view.widthAnchor) .isActive = true nameLabel.heightAnchor.constraint(greaterThanOrEqualTo: view.heightAnchor).isActive = true nameLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true nameLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
61. nameLabel.translatesAutoresizingMaskIntoConstraints = false nameLabel.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.2, constant: 10).isActive = true nameLabel.heightAnchor.constraint(greaterThanOrEqualTo: view.heightAnchor, multiplier: 0.2).isActive = true nameLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 0).isActive = true nameLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0).isActive = true
62. nameLabel .setAnchor(\.widthAnchor, .equal, to: view.widthAnchor) .setAnchor(\.heightAnchor, .greaterThanOrEqual, to: view.heightAnchor) .setAnchor(\.topAnchor, .equal, to: view.topAnchor) .setAnchor(\.centerXAnchor, .equal, to:view.centerXAnchor)
63. nameLabel .setAnchor(\.widthAnchor, .equal, to: view.widthAnchor, constant: 10, multiplier: 0.2) .setAnchor(\.heightAnchor, .greaterThanOrEqual, to: view.heightAnchor, multiplier: 0.2) .setAnchor(\.topAnchor, .equal, to: view.topAnchor) .setAnchor(\.centerXAnchor, .equal, to:view.centerXAnchor)
64. let topConstraint = label.setConstraint(\.topAnchor, .equal, to: view.topAnchor) nameLabel .setAnchor(\.widthAnchor, .equal, to: view.widthAnchor, constant: 10, multiplier: 0.2) .setAnchor(\.heightAnchor, .greaterThanOrEqual, to: view.heightAnchor, multiplier: 0.2) .setAnchor(\.topAnchor, .equal, to: view.topAnchor) .setAnchor(\.centerXAnchor, .equal, to:view.centerXAnchor)
65. ( _ keyPath: KeyPath<UIView, LayoutType>, _ relation: NSLayoutConstraint.Relation, to anchor: LayoutType, ) -> NSLayoutConstraint { translatesAutoresizingMaskIntoConstraints = false return constraint } constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required if let multiplier = multiplier, //... } else { //... } @discardableResult func setConstraint let constraint: NSLayoutConstraint constraint.priority = priority constraint.isActive = true <LayoutType: NSLayoutAnchor<AnchorType>, AnchorType>
66. ( _ keyPath: KeyPath<UIView, LayoutType>, _ relation: NSLayoutConstraint.Relation, to anchor: LayoutType, ) -> NSLayoutConstraint { translatesAutoresizingMaskIntoConstraints = false return constraint } constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required if let multiplier = multiplier, //... } else { //... } @discardableResult func setConstraint let constraint: NSLayoutConstraint constraint.priority = priority constraint.isActive = true <LayoutType: NSLayoutAnchor<AnchorType>, AnchorType>
67. ( _ keyPath: KeyPath<UIView, LayoutType>, _ relation: NSLayoutConstraint.Relation, to anchor: LayoutType, ) -> NSLayoutConstraint { translatesAutoresizingMaskIntoConstraints = false return constraint } constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required if let multiplier = multiplier, //... } else { //... } @discardableResult func setConstraint let constraint: NSLayoutConstraint constraint.priority = priority constraint.isActive = true <LayoutType: NSLayoutAnchor<AnchorType>, AnchorType>
68. ( _ keyPath: KeyPath<UIView, LayoutType>, _ relation: NSLayoutConstraint.Relation, to anchor: LayoutType, ) -> NSLayoutConstraint { translatesAutoresizingMaskIntoConstraints = false return constraint } constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required if let multiplier = multiplier, //... } else { //... } @discardableResult func setConstraint let constraint: NSLayoutConstraint constraint.priority = priority constraint.isActive = true <LayoutType: NSLayoutAnchor<AnchorType>, AnchorType>
69. if let multiplier = multiplier, let dimension = self[keyPath: keyPath] as? NSLayoutDimension, let anchor = anchor as? NSLayoutDimension { //... } else { //... } to anchor: LayoutType, constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required @discardableResult ( _ keyPath: KeyPath<UIView, LayoutType>, _ relation: NSLayoutConstraint.Relation, to anchor: LayoutType, ) -> NSLayoutConstraint { translatesAutoresizingMaskIntoConstraints = false constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required @discardableResult func setConstraint let constraint: NSLayoutConstraint constraint.priority = priority constraint.isActive = true <LayoutType: NSLayoutAnchor<AnchorType>, AnchorType>
70. if let multiplier = multiplier, let dimension = self[keyPath: keyPath] as? NSLayoutDimension, let anchor = anchor as? NSLayoutDimension { //... } else { //... } to anchor: LayoutType, constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required @discardableResult ( _ keyPath: KeyPath<UIView, LayoutType>, _ relation: NSLayoutConstraint.Relation, to anchor: LayoutType, ) -> NSLayoutConstraint { translatesAutoresizingMaskIntoConstraints = false constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required @discardableResult func setConstraint let constraint: NSLayoutConstraint constraint.priority = priority constraint.isActive = true <LayoutType: NSLayoutAnchor<AnchorType>, AnchorType>
71. if let multiplier = multiplier, let dimension = self[keyPath: keyPath] as? NSLayoutDimension, let anchor = anchor as? NSLayoutDimension { switch relation { //NSLayoutDimension //... } } else { switch relation { //NSLayoutAnchor //... } }
72. switch relation { //NSLayoutDimension case .equal: constraint = dimension .constraint(equalTo: anchor, multiplier:multiplier, constant: constant) case .greaterThanOrEqual: constraint = dimension .constraint(greaterThanOrEqualTo: anchor, multiplier: multiplier, constant: constant) case .lessThanOrEqual: constraint = dimension .constraint(lessThanOrEqualTo: anchor, multiplier: multiplier, constant: constant) }
73. switch relation { //NSLayoutAnchor case .equal: constraint = self[keyPath: keyPath] .constraint(equalTo: anchor, constant: constant) case .greaterThanOrEqual: constraint = self[keyPath: keyPath] .constraint(greaterThanOrEqualTo: anchor, constant: constant) case .lessThanOrEqual: constraint = self[keyPath: keyPath] .constraint(lessThanOrEqualTo: anchor, constant: constant) }
74. @discardableResult <LayoutType: NSLayoutAnchor<AnchorType>, AnchorType>( ) -> Self { setConstraint(keyPath, relation, to: anchor, constant: constant, multiplier: multiplier, priority: priority) return self } _ keyPath: KeyPath<UIView, LayoutType>, _ relation: NSLayoutConstraint.Relation, to anchor: LayoutType, constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required func setAnchor
75. @discardableResult <LayoutType: NSLayoutAnchor<AnchorType>, AnchorType>( ) -> Self { setConstraint(keyPath, relation, to: anchor, constant: constant, multiplier: multiplier, priority: priority) return self } _ keyPath: KeyPath<UIView, LayoutType>, _ relation: NSLayoutConstraint.Relation, to anchor: LayoutType, constant: CGFloat = 0, multiplier: CGFloat? = nil, priority: UILayoutPriority = .required func setAnchor
76. nameLabel.translatesAutoresizingMaskIntoConstraints = false nameLabel.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.2, constant: 10) .isActive = true nameLabel.heightAnchor.constraint(greaterThanOrEqualTo: view.heightAnchor, multiplier: 0.2).isActive = true nameLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 0).isActive = true nameLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0).isActive = true descLabel.translatesAutoresizingMaskIntoConstraints = false descLabel.widthAnchor.constraint(equalTo: view.widthAnchor, multiplier: 0.9, constant: 10) .isActive = true descLabel.heightAnchor.constraint(greaterThanOrEqualTo: view.heightAnchor) .isActive = true descLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 0).isActive = true descLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0).isActive = true
77. nameLabel .setAnchor(\.widthAnchor, .equal, to: view.widthAnchor, constant: 10, multiplier: 0.2) .setAnchor(\.heightAnchor, .greaterThanOrEqual, to: view.heightAnchor, multiplier: 0.2) .setAnchor(\.centerXAnchor, .equal, to: view.centerXAnchor) .setAnchor(\.topAnchor, .equal, to: view.topAnchor) descLabel .setAnchor(\.widthAnchor, .equal, to: view.widthAnchor, multiplier: 0.2) .setAnchor(\.heightAnchor, .greaterThanOrEqual, to: view.heightAnchor) .setAnchor(\.centerXAnchor, .equal, to: view.centerXAnchor) .setAnchor(\.centerYAnchor, .equal, to: view.centerYAnchor)
78. Conclusion
79. • Swift KeyPath is a defer way to get / set property with Type safety
80. • Swift KeyPath is a defer way to get / set property with Type safety • Better Key-Value Coding for Swift (Compared with #KeyPath( ) )
81. • Swift KeyPath is a defer way to get / set property with Type safety • Better Key-Value Coding for Swift • Create interface more flexible than ever (Compared with #KeyPath( ) )
82. • Swift KeyPath is a defer way to get / set property with Type safety • Better Key-Value Coding for Swift • Create interface more flexible than ever (Compared with #KeyPath( ) ) • Easy to implement Fluent Interface!
83. WWDC17 - What's New in Foundation https://developer.apple.com/videos/play/wwdc2017/212/ Proposal: SE-0161 https://github.com/apple/swift-evolution/blob/master/proposals/0161-key-paths.md Proposal SE-0252 https://github.com/apple/swift-evolution/blob/master/proposals/0252-keypath- dynamic-member-lookup.md Introduction to Swift Keypaths - Benedikt Terhechte
 http://www.swifttube.co/video/the-underestimated-power-of-keypaths The underestimated power of KeyPaths - Vincent Pradeilles http://www.swifttube.co/video/the-underestimated-power-of-keypaths FluentInterface https://martinfowler.com/bliki/FluentInterface.html Builder, Fluent Interface and classic builder https://medium.com/@sawomirkowalski/design-patterns-builder-fluent-interface- and-classic-builder-d16ad3e98f6c Reference
84. Proposal SE-0249 https://github.com/apple/swift-evolution/blob/master/proposals/0249-key-path-literal- function-expressions.md KeyPathKit - Vincent Pradeilles https://github.com/vincent-pradeilles/KeyPathKit The power of key paths in Swift - Sundell https://www.swiftbysundell.com/articles/the-power-of-key-paths-in-swift/ Using Swift KeyPaths for Beautiful User Preferences - Kane https://edit.theappbusiness.com/using-swift-keypaths-for-beautiful-user- preferences-c83c2f7ea7be More Information
85. 活動時間： 每週⼆ pm: 7:30 ~ 10:00 活動地點：建國北路⼆段1號5樓 ( Meet.jobs 辦公室 ) (感謝Meet.jobs 提供場地)
86. Thanks for your attention.