Я расскажу о нестандартных особенностях языка для реальных проектов. Речь пойдет о том, зачем усложнять себе жизнь и какие преимущества это может дать. - Protocol-Oriented Programming и его дилеммы - Когда и зачем использовать обобщения и вложенные типы - Настоящее и будущее Swift

2. 2
• Nested Types
• Generics
• Protocols
• Protocol-Oriented Programming
• Mirror Type and Reflection

3. 3
Why Swift?

4. 4
It’s fast 🚀 It’s powerful 💪 It’s awesome 🏆
Why Swift?

5. 5
Colors

6. 6
Colors

7. 7
view.backgroundColor =
UIColor(hexString: "6094EA")
view.backgroundColor = UIColor(.strongGray)
view.backgroundColor = UIColor.strongGray

8. 8
Expectation RealityOld

9. 9
extension UIColor {
static var tableElementsSeparator: UIColor {
return UIColor(.strongGray)
}
static var barsSeparator: UIColor {
return UIColor(.red)
}
static var barsBackground: UIColor {
return UIColor(.gray)
}
}
Type Omission

10. 10
extension UIColor {
static var tableElementsSeparator: UIColor {
return UIColor(.strongGray)
}
static var barsSeparator: UIColor {
return UIColor(.red)
}
static var barsBackground: UIColor {
return UIColor(.gray)
}
static var toolBox: UIColor {
return UIColor(.gray)
}
static var activeControl: UIColor {

11. 11
extension UIColor {
static var tableElementsSeparator: UIColor {
return UIColor(.strongGray)
}s
static var barsSeparator: UIColor {
return UIColor(.red)
}s
static var barsBackground: UIColor {
return UIColor(.gray)
}s
}s

12. 12
extension UIColor {
struct Separator {
static var tableElements: UIColor {
return UIColor(.strongGray)
}s
static var bars: UIColor {
return UIColor(.red)
}s
}
}s
Struct Enum

13. 13
extension UIColor {
enum Separator {
static var tableElements: UIColor {
return UIColor(.strongGray)
}s
static var bars: UIColor {
return UIColor(.red)
}s
}
}s

14. 14
let activeStateColor =
UIColor.Control.Button.activeStateTitle
button.setTitleColor(activeStateColor, for: .normal)

15. 15
Generics

16. 16
Generics<T>

17. 17

18. 18
struct StoriesDisplayCollection {
var stories: Results<StoryEntity>
var count: Int {
return stories.count
}
func nameAtIndex(index: Int) -> String {
return stories[index].name
}
}

19. 19
struct StoriesDisplayCollection {
var stories: Results<StoryEntity>
var count: Int {
return stories.count
}
func nameAtIndex(index: Int) -> String {
return stories[index].name
}
}
Stories

20. 20
struct StoriesDisplayCollection {
var stories: Results<StoryEntity>
var count: Int {
return stories.count
}
func nameAtIndex(index: Int) -> String {
return stories[index].name
}
}

21. 21
struct StoriesDisplayCollection {
var stories: Results/List<StoryEntity>
}
struct StoriesDisplayCollection {
var stories: TemplateModelsCollection<StoryEntity>
}

22. 22
struct TemplateModelsCollection<T: TemplateEntity>
where T: Object {
}

23. 23
enum Content {
case result(Results<T>)
case list(List<T>)
case empty
subscript(index: Int) -> T {
switch self {
case let .result(model):
return model[index]
case let .list(list):
return list[index]
case .empty:
return T.templateEntity
}
}
}
Nested
Same T, Swift 3.1+

24. 24
struct TemplateModelsCollection<T: TemplateEntity>
where T: Object {
init(dataCollection: Results<T>, templatesCount: Int = 5) {
content = Content.result(dataCollection)
values = List<T>()
generateFakeData(templatesCount: templatesCount)
}
}
Template One

25. 25
struct TemplateModelsCollection<T: TemplateEntity>
where T: Object {
var count: Int {
if isLoading && content.count == 0 {
return values.count
} else {
return content.count
}
}
}
Template One

26. 26

27. 27
Protocols

28. 28
protocol Summable {
static func +(lhs: Self, rhs: Self) -> Self
}
extension Int: Summable { }
extension String: Summable { }
public func +(lhs: Int, rhs: Int) -> Int
public func +(lhs: String, rhs: String) -> String

29. 29
protocol Summator {
associatedtype Value
func sum(a: Value, b: Value) -> Value
}

30. 30
protocol Summator {
associatedtype Value
func sum(a: Value, b: Value) -> Value
}
extension Summator where Value: Summable {
func sum(a: Value, b: Value) -> Value {
return a + b
}
}

31. 31
struct IntSummator: Summator {
typealias Value = Int
}
let summator = IntSummator()
print(summator.sum(a: 5, b: 10)) // 15

32. 32
• We have Self/associatedtype for future type
implementation
• We can specify rules for associatedtype
• We can extend protocols with logic
• We can specify constraints for protocol extensions

33. 33
Protocol-Oriented
Programming

34. 34
youtube.com/watch?v=71AS4rMrAVk

35. 35
• Value Type over Reference Type
• No inheritance
• No mutability
• Advanced usage of protocols and its extensions

36. 36Array
RandomAccessCollection MutableCollection
BidirectionalCollection
Sequence
Collection

37. 37
Array
RandomAccessCollection
MutableCollection
BidirectionalCollection
Sequence
Collection
ExpressibleByArrayLiteral
CustomReflectable
RangeReplaceableCollection
CustomStringConvertible
CustomDebugStringConvertible

38. 38
Array
RandomAccessCollection
MutableCollection
BidirectionalCollection
Sequence
Collection
ExpressibleByArrayLiteral
CustomReflectable
RangeReplaceableCollection
CustomStringConvertible
CustomDebugStringConvertible
_ArrayProtocol
_ObjectiveCBridgeable
Encodable
Decodable
MyArrayBufferProtocol
MyPrintable
P5
SplittableCollection
BuildableCollectionProtocol
MutableCollectionAlgorithms

39. 39
Array
RandomAccessCollection
MutableCollection
BidirectionalCollection
Sequence
Collection
ExpressibleByArrayLiteral
CustomReflectable
RangeReplaceableCollection
CustomStringConvertible
CustomDebugStringConvertible
Dictionary
Collection
CustomStringConvertible
CustomDebugStringConvertible
CustomReflectable
Sequence
-
-
ExpressibleByDictionaryLiteral
-
-

40. 40
Array
RandomAccessCollection
MutableCollection
BidirectionalCollection
Sequence
Collection
ExpressibleByArrayLiteral
CustomReflectable
RangeReplaceableCollection
CustomStringConvertible
CustomDebugStringConvertible
List
Realm One
RandomAccessCollection
LazyCollectionProtocol
BidirectionalCollection
Sequence
Collection
ExpressibleByArrayLiteral
RealmCollection
RangeReplaceableCollection
CustomStringConvertible
ThreadConfined

41. 41
extension Collection where Index == Int {
var second: Iterator.Element? {
guard self.count > 1 else { return nil }
return self[1]
}
}
var array = ["A", "B", "C"]
print(array.second) // Optional("B")

42. 42
extension Collection where Index == Int {
var second: Iterator.Element? {
guard self.count > 1 else { return nil }
return self[1]
}
}
var array = ["A", "B", "C"]
print(array.second) // Optional("B")
Protocol

43. 43
Swift 3.1+
extension Collection where Index == Int {
var second: Iterator.Element? {
guard self.count > 1 else { return nil }
return self[1]
}
}
var array = ["A", "B", "C"]
print(array.second) // Optional("B")

44. 44
extension Collection where Index == Int {
var second: Iterator.Element? {
guard self.count > 1 else { return nil }
return self[1]
}
}
var array = ["A", "B", "C"]
print(array.second) // Optional("B")
Generic Element

45. 45
extension Collection where Index == Int {
var second: Iterator.Element? {
guard self.count > 1 else { return nil }
return self[1]
}
}
var array = ["A", "B", "C"]
print(array.second) // Optional("B")
Index == Int
subscript(position: Self.Index)
-> Self.Iterator.Element { get }

46. 46
extension Collection where Index == Int {
var second: Iterator.Element? {
guard self.count > 1 else { return nil }
return self[1]
}
}
var array = ["A", "B", "C"]
print(array.second) // Optional("B")

47. 47
• Follow I from SOLID
• Implement default behaviour in protocol extensions
• Implement generic based behaviour
• Combine multiply protocols or “inherit” them
The interface-segregation principle (ISP) states that no client
should be forced to depend on methods it does not use.

48. 48

49. 49
protocol CellViewModel {
associatedtype CellType: UIView
func setup(cell: CellType)
}
Generic
Generic

50. 50
protocol CellViewModel: CellViewAnyModel {
associatedtype CellType: UIView
func setup(cell: CellType)
}
Non generic

51. 51
protocol CellViewAnyModel {
static var cellAnyType: UIView.Type { get }
func setupAny(cell: UIView)
}
associatedtype CellType: UIView
func setup(cell: CellType)

52. 52
extension CellViewModel {
static var cellAnyType: UIView.Type {
return CellType.self
}
func setupAny(cell: UIView) {
setup(cell: cell as! CellType)
}
}
!!!

53. 53
• https://github.com/JohnSundell/SwiftTips
• https://developer.apple.com/swift/blog/
• https://swift.org/blog/
• https://swiftnews.curated.co
• https://www.raizlabs.com/dev/2016/12/swift-method-
dispatch/
• https://github.com/ole/whats-new-in-swift-4

54. 54
• https://github.com/JohnSundell/SwiftTips
• https://developer.apple.com/swift/blog/
• https://swift.org/blog/
• https://swiftnews.curated.co
• https://www.raizlabs.com/dev/2016/12/swift-method-
dispatch/
• https://github.com/ole/whats-new-in-swift-4

55. 55
@ZiminAlex