I love swift.pdf

The Swift overview and the best parts of it

Transcript

1. ❤ Swift I Konstantin Koval @KostiaKoval
2. Swift •Static •Strong typing •Type Safe •Fast •Object Oriented •Functional •Generic Purpose •Nice and Clean
3. Swift Code class Person { var age = 0 var name = "" let birthDate: NSDate init(age: Int, name: String) { self.age = age self.name = name birthDate = NSDate.date() } func hello() { println("Hello \(name)") } } ! let me = Person(age: 26, name: "Konstantin") me.hello()
4. Swift Code class Person { var age = 0 var name = "" let birthDate: NSDate init(age: Int, name: String) { self.age = age self.name = name birthDate = NSDate.date() } func hello() { println("Hello \(name)") } } ! let me = Person(age: 26, name: "Konstantin") me.hello() Objective-C @interface Person : NSObject { ! NSInteger age; NSString *name; NSDate *birthDate; } - (instancetype)initWith:(NSInteger)age name:(NSString *)name; - (void)hello; ! @end ! @implementation Person ! - (instancetype)initWith:(NSInteger)anAge name:(NSString *)aName { ! self = [super init]; if (self) { age = anAge; name = aName; birthDate = [NSDate date]; } return self; } ! - (void)hello { NSLog(@"%@",[NSString stringWithFormat:@"Hello %@", name]); } ! @end !
5. Static - Strong - Safe
6. var myAge = 26 var myWifeAge: Int ! ! Static - Strong - Safe
7. var myAge = 26 var myWifeAge: Int ! var ourAge = myAge + myWifeAge ! Static - Strong - Safe
8. var myAge = 26 var myWifeAge: Int ! myWifeAge = 18 ! var ourAge = myAge + myWifeAge ! Static - Strong - Safe
9. var myAge = 26 var myWifeAge: Int ! myWifeAge = 18 ! var ourAge = myAge + myWifeAge ! ourAge += 1.23 ourAge.count ! Static - Strong - Safe
10. var myAge = 26 var myWifeAge: Int ! myWifeAge = 18 ! var ourAge = myAge + myWifeAge ! var numbers = [1,2,3] numbers.count ! numbers.append(4) numbers.append("10") ! Static - Strong - Safe
11. Nil, or not Nil That is the question
12. // Java and C++ Person person; person.name; // NullPointerException A bit of History
13. // Java and C++ Person person = Person(); person.name; A bit of History
14. // Java and C++ Person person = Person(); person.name; A bit of History // Objective-C Person* person; person.name; // no Exception when access nil
15. // Java and C++ Person person = getPerson(); person.name; A bit of History // Objective-C Person* person; person.name; // no Exception when access nil // Java and C++ public Person getPerson () { Person(); }
16. A bit of History // Java and C++ Person person = getPerson(); person.name; // Objective-C Person* person; person.name; // no Exception when access nil // Java and C++ public Person getPerson () { ! Person person = fetchFromServer(); person = validate(person) person = checkCreditHistory(person) return person //person is nil }
17. A bit of History // Java and C++ Person person = getPerson(); person.name; // NullPointerException // Objective-C Person* person; person.name; // no Exception when access nil // Java and C++ public Person getPerson () { ! Person person = fetchFromServer(); person = validate(person) person = checkCreditHistory(person) return person //person is nil }
18. A bit of History // Java and C++ Person person = getPerson(); if(person != null) { person.name; } // Objective-C Person* person; person.name; // no Exception when access nil // Java and C++ public Person getPerson () { ! Person person = fetchFromServer(); person = validate(person) person = checkCreditHistory(person) return person //person is nil }
19. A bit of History // Java and C++ Person person = getPerson(); if(person != null) { person.name; } // Objective-C Person* person; if(person) { NSString *name = person.name; if(name) { //Use name } } // Java and C++ public Person getPerson () { ! Person person = fetchFromServer(); person = validate(person) person = checkCreditHistory(person) return person //person is nil }
20. A bit of History // Java and C++ Person person = getPerson(); if(person != null) { person.name; } // Objective-C Person* person; if(person) { NSString *name = person.name; if(name) { //Use name } } // Java and C++ public Person getPerson () { ! Person person = fetchFromServer(); person = validate(person) person = checkCreditHistory(person) return person //person is nil } nil for Scalar value
21. A bit of History // Java and C++ Person person = getPerson(); if(person != null) { person.name; } // Objective-C Person* person; if(person) { NSString *name = person.name; if(name) { //Use name } } // Java and C++ public Person getPerson () { ! Person person = fetchFromServer(); person = validate(person) person = checkCreditHistory(person) return person //person is nil } nil for Scalar value 0 -1 NSNotFound IntMax NULL
22. Nil Nil Everywhere!
23. Solution ?!?
24. Solution ?!? We need language that has a type interface for ! • Value • Maybe a Value or Noting
25. Optionals ! enum Optional<T> { case None case Some(T) }
26. Optionals ! enum Optional<T> { case None case Some(T) } var a: Int var b: Int?
27. Optionals ! enum Optional<T> { case None case Some(T) } func getInt() -> Int { return 10 } func tryGetInt() -> Int? { return nil } ! var a: Int = getInt() var b: Int? = tryGetInt()
28. Optionals ! enum Optional<T> { case None case Some(T) } func getInt() -> Int { return 10 } func tryGetInt() -> Int? { return nil } ! var a: Int = getInt() var b: Int? = tryGetInt() var c: Int? = 20
29. Optionals ! func getPerson () ->Person { return Person() } ! var person = getPerson() person.name ! ! var maybePerson: Person? ! if maybePerson != nil { maybePerson!.name //unwrap optional with ! } ! if let actualPerson = maybePerson { actualPerson.name }
30. Optionals ! func getPerson () ->Person { return Person() } ! var person = getPerson() person.name ! ! var maybePerson: Person? ! if maybePerson != nil { maybePerson!.name //unwrap optional with ! } ! if let actualPerson = maybePerson { actualPerson.name } ! var person: Person? if let person = person { person.name }
31. Functional
32. Functional • First-class function
 - assign a function to variable
 - pass function as argument to other function 
 - return a function from a function • Closures • Functional programming patterns, : map, filter, etc
33. Functional func nothing() func printNumber(a : Int) func increase(a: Int) -> Int func call(aFunc: (Int) -> (Int) ) -> (Int, Int) ->(Int) () -> () (Int) -> () (Int) -> (Int) ((Int) -> (Int)) -> ((Int, Int) -> (Int))
34. Functional var c = { (s1: String, s2: String) -> Bool in return s1 > s2 } c = { s1, s2 in return s1 > s2 } c = { s1, s2 in s1 > s2 } c = { $0 > $1 } ! (String, String) -> (Bool)
35. Functional var ar = [1,2,3] // Increase every value in array
36. Functional var ar = [1,2,3] // Increase every value in array func increase(ar :[Int], #by: Int) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { result[i] += by } return result }
37. Functional var ar = [1,2,3] ar = increase(ar, by:10) // [11, 12, 13] func increase(ar :[Int], #by: Int) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { result[i] += by } return result }
38. Functional var ar = [1,2,3] ar = increase(ar, by:10) // Decrease every value in array func increase(ar :[Int], #by: Int) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { result[i] += by } return result }
39. Functional var ar = [1,2,3] ar = increase(ar, by:10) // Decrease every value in array func increase(ar :[Int], #by: Int) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { result[i] += by } return result } ! func decrease(ar :[Int], #by: Int) -> [Int] { var result = ar for var i = 0; i < ar.count; i++ { result[i] -= by } return result }
40. Functional var ar = [1,2,3] ar = increase(ar, by:10) ar = decrease(ar, by:5) // [6, 7, 8] func increase(ar :[Int], #by: Int) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { result[i] += by } return result } ! func decrease(ar :[Int], #by: Int) -> [Int] { var result = ar for var i = 0; i < ar.count; i++ { result[i] -= by } return result }
41. func decrease(ar :[Int], #by: Int) -> [Int] { var result = ar for var i = 0; i < ar.count; i++ { result[i] -= by } return result } Functional func increase(ar :[Int], #by: Int) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { result[i] += by } return result }
42. func decrease(ar :[Int], #by: Int) -> [Int] { var result = ar for var i = 0; i < ar.count; i++ { result[i] -= by } return result } Functional func increase(ar :[Int], #by: Int) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { result[i] += by } return result } it’s start to smell like a Shit
43. Functional var ar = [1,2,3] func modify(ar: [Int]) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { // Do operation } return result }
44. Functional var ar = [1,2,3] func modify(ar: [Int], operation: (Int) ->(Int) ) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { // Do operation result[i] = operation(ar[i]) } return result }
45. Functional var ar = [1,2,3] ar = modify(ar, operation: plusOne) func modify(ar: [Int], operation: (Int) ->(Int) ) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { // Do operation result[i] = operation(ar[i]) } return result } ! ! func plusOne(a: Int ) -> Int { return a + 1 }
46. Functional var ar = [1,2,3] ar = modify(ar) { $0 + 1 } ar = modify(ar) { $0 - 2 } ar = modify(ar) { $0 * 2 } func modify(ar: [Int], operation: (Int) ->(Int) ) -> [Int] { ! var result = ar for var i = 0; i < ar.count; i++ { // Do operation result[i] = operation(ar[i]) } return result }
47. Functional var ar = [1,2,3] ! ar.map { $0 - 2 } ar.filter { $0 % 2 == 0 } ar.reduce(0, combine: +)
48. OOP
49. OOP •Classes •Protocols •Properties • Methods • Initialisers • Deinitializers • Property observers • Inheritance • Access control • Lazy loading • Subscript All the feature of modern OOP Language
50. OOP class Person { var age = 0 var name = "Default" var secondName = "Default" lazy var importer = DataImporter() ! init(age: Int, name: String) { self.age = age self.name = name } ! deinit { println("say goodbye") } func hello() { println("Hello \(name)") } var fullName: String { return name + " " + secondName } }
51. OOP class Parent : Person { ! var children :[Person] override init(age: Int, name: String) { children = [] super.init(age: age, name: name) } override var age: Int { willSet { println("age will be changed") } didSet { println("age is changed") } } subscript(index: Int) -> Person { get { return children[index] } set(newValue) { children[index] = newValue } } }
52. Objects Initialisations • Must set value for all the properties • After memory is fully initialised can access self • Subclasses initialisers must delegate up (call super.init) • Designated and Connivance initialisers • Not inherited by default
53. Objects Initialisations class Parent : Person { var childName ! init(children: [Person], age: Int, name: String) { self.children = children super.init(age: age, name: name) } }
54. Objects Initialisations class Parent : Person { var childName ! init(children: [Person], age: Int, name: String) { self.children = children super.init(age: age, name: name) } ! override init(age: Int, name: String) { children = [] super.init(age: age, name: name) } }
55. Objects Initialisations class Parent : Person { var childName ! init(children: [Person], age: Int, name: String) { self.children = children super.init(age: age, name: name) } ! override init(age: Int, name: String) { children = [] super.init(age: age, name: name) } ! ! convenience init () { self.init(age:0, name:"") } }
56. Generics
57. Generics • Flexible, reusable functions and types that can work with any type ! • Less boilerplate code
58. Generics var a = 10 var b = 20 ! swapInt(&a, &b) func swapInt(inout a: Int, inout b: Int) { let tmp = a a = b b = tmp }
59. Generics var a = 10 var b = 20 ! swapInt(&a, &b) ! var str1 = "One" var str2 = “Two" func swapInt(inout a: Int, inout b: Int) { let tmp = a a = b b = tmp } !
60. Generics var a = 10 var b = 20 ! swapInt(&a, &b) ! var str1 = "One" var str2 = “Two" func swapInt(inout a: Int, inout b: Int) { let tmp = a a = b b = tmp } ! func swapSting(inout a: String, inout b: String) { let tmp = a a = b b = tmp }
61. Generics var a = 10 var b = 20 ! swapInt(&a, &b) ! var str1 = "One" var str2 = “Two” ! swapSting(&str1, &str2) func swapInt(inout a: Int, inout b: Int) { let tmp = a a = b b = tmp } ! func swapSting(inout a: String, inout b: String) { let tmp = a a = b b = tmp }
62. Generics var a = 10 var b = 20 ! swapInt(&a, &b) ! var str1 = "One" var str2 = “Two” ! swapSting(&str1, &str2) func swapInt(inout a: Int, inout b: Int) { let tmp = a a = b b = tmp } ! func swapSting(inout a: String, inout b: String) { let tmp = a a = b b = tmp }
63. Generics var a = 10 var b = 20 ! swapInt(&a, &b) ! var str1 = "One" var str2 = “Two” ! swapSting(&str1, &str2) func swapInt(inout a: Int, inout b: Int) { let tmp = a a = b b = tmp } ! func swapSting(inout a: String, inout b: String) { let tmp = a a = b b = tmp } Do you feel this smell ??
64. Generics var a = 10 var b = 20 var str1 = "One" var str2 = “Two” ! swap(&a, &b) swap(&str1, &str2) func swap<T>(inout a: T, inout b: T) { let tmp = a a = b b = tmp }
65. Generics var a = 10 var b = 20 var str1 = "One" var str2 = “Two” ! swap(&a, &b) swap(&str1, &str2) ! min(1, 10) min("a", "J") func swap<T>(inout a: T, inout b: T) { let tmp = a a = b b = tmp } ! func min<T : Comparable>(x: T, y: T) -> T { return x < y ? x : y }
66. Generics var a = 10 var b = 20 var str1 = "One" var str2 = “Two” ! swap(&a, &b) swap(&str1, &str2) ! min(1, 10) min("a", “J") minElement(10, 3, 1, 4) func min<T : Comparable>(x: T, y: T) -> T { return x < y ? x : y } ! func minElement<R : SequenceType where R.Element : Comparable>(range: R) -> R.Generator.Element { ! var min: R.Element? for object in range { if min == nil || object < min { min = object } } return min! }
67. Immutable
68. Immutable • Immutable variables keyword • Struct are immutable
69. Immutable var name = "Konstantin" name = "Tomas" name += " Super” ! let superName = "Super Konstantin”
70. Immutable var name = "Konstantin" name = "Tomas" name += " Super” ! let superName = "Super Konstantin” ! superName = "Tomas" superName += "and Tomas" !
71. Immutable var name = "Konstantin" name = “Tomas" name += " Super” ! let superName = "Super Konstantin” ! var people = ["Jon", "Sam"] people.append("Arnold") // ["Jon", "Sam", "Arnold"] ! let superPeople = ["Konstantin", "Rikke"] !
72. Immutable var name = "Konstantin" name = “Tomas" name += " Super” ! let superName = "Super Konstantin” ! var people = ["Jon", "Sam"] people.append("Arnold") // ["Jon", "Sam", "Arnold"] ! let superPeople = ["Konstantin", "Rikke"] superPeople.append("Tomas") !
73. Immutable struct Rocketfarm { ! var people: [String] mutating func append (person: String) { people.append(person) } } ! var rocket = Rocketfarm(people: ["Halvor", "Jørn", "Dyre"]) rocket.append("Konstantin") !
74. Immutable struct Rocketfarm { ! var people: [String] mutating func append (person: String) { people.append(person) } } ! var rocket = Rocketfarm(people: ["Halvor", "Jørn", "Dyre"]) rocket.append("Konstantin") ! let secondRocket = rocket secondRocket.append("Lars") !
75. Tuples
76. Tuples • Group multiple values into a single compound value • Can be of any type • Do not have to be of the same type • Tuples are particularly useful as the return values of functions.
77. Tuples let http404Error = (404, "Not Found”) http404Error.0 http404Error.1 ! let http200Error = (statusCode:404, description:"Not Found") http200Error.statusCode http200Error.description !
78. Tuples func getServerContent() ->(data: String?, error:(errorCode: Int, description: String)? ) { return ("data from server", nil) } ! let res = getServerContent() ! res.error res.data ! if let error = res.error { println("Error \(error.description) with code: \(error.errorCode)") }
79. Custom Operators
80. Custom Operators Why ? - Make code more verbose and readable
81. Custom Operators • Overload existing operator for new types • Create new operator Why ? - Make code more verbose and readable
82. Custom Operators public class Rocketfarm { var people: [String] = [] ! func append (person: String) { people.append(person) } } var rocket = Rocketfarm() rocket.append("Konstantin")
83. Custom Operators public class Rocketfarm { var people: [String] = [] ! func append (person: String) { people.append(person) } } var rocket = Rocketfarm() rocket.append("Konstantin") ! rocket + "Stian" rocket << "Dyre"
84. Custom Operators public class Rocketfarm { var people: [String] = [] ! func append (person: String) { people.append(person) } } ! public func + (rocket: Rocketfarm, person: String) -> Rocketfarm { var newRocket = rocket newRocket.append(person) return newRocket } ! public func << (rocket: Rocketfarm, person: String) -> Rocketfarm { return rocket + person } var rocket = Rocketfarm() rocket.append("Konstantin") ! rocket + "Stian" rocket << "Dyre"
85. Custom Operators var rocket = Rocketfarm() rocket.append("Konstantin") ! rocket + "Stian" rocket << “Dyre" ! rocket^^^
86. Custom Operators var rocket = Rocketfarm() rocket.append("Konstantin") ! rocket + "Stian" rocket << “Dyre" ! rocket^^^ ! postfix operator ^^^ {}
87. Custom Operators var rocket = Rocketfarm() rocket.append("Konstantin") ! rocket + "Stian" rocket << “Dyre" ! rocket^^^ ! postfix operator ^^^ {} postfix func ^^^ (rocket: Rocketfarm) -> Rocketfarm { var newRocket = rocket newRocket.people.removeAll() return newRocket }
88. Pattern Matching
89. Pattern Matching It’s very smart switch statement
90. Pattern Matching It’s very smart switch statement • Must be exhaustive, (handle all cases) • Implicit Fall through • Range Matching • Value Bindings • Where condition
91. Pattern Matching let size = (20, 40) ! switch size { ! case (0, 0): println("(0, 0) rect”) ! default: println("some rectangle") }
92. Pattern Matching let size = (20, 40) ! switch size { ! case (0, 0): println("(0, 0) rect”) ! case let (width, height) where width == height: println("square with sides \(width)”) ! case (1...10, 1...10): println("small rectangle”) ! case let (width, height): println("rectangle with width \(width) and height \(height)") }
93. Pattern Matching let integerToDescribe = 5 var description = "The number \(integerToDescribe) is" ! switch integerToDescribe { ! case 2, 3, 5, 7, 11, 13, 17, 19: description += " a prime number, and also" fallthrough ! default: description += " an integer." }
94. Seamless migration
95. Seamless migration Swift Objective-C • 100 % Objective-C code available in swift • Automatically generated interface headers • All standard frameworks • All custom libraries (All the goodies from Github) • 80 % Swift code available in swift Swift features (Tuples, Optionals) is not available • Mark Swift class as Objective-C compatible @objc
96. Seamless migration Swift var view = UIView() view.backgroundColor = UIColor.greenColor() var label = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 100)) label.text = "Happinessssss!"
97. Seamless migration Swift Objective-C @objc class A { ! var name = "Name" lazy var subName = " " var count: Int? var tuple = (10, "Ten") class func newInstance () -> A { return A() } ! func hello() { println("Hello") } } #import “ProjectName-Swift.h" ! A* a = [A newInstance]; [a hello]; a.name; a.subName; ! // Not available a.count; a.tuple;
98. Seamless migration “ProjectName-Swift.h" File content "ProjectName-Swift.h" ! SWIFT_CLASS("_TtC9ProjectNameA") @interface A @property (nonatomic, copy) NSString * name; @property (nonatomic, copy) NSString * subName; - (instancetype)init OBJC_DESIGNATED_INITIALIZER; + (A *)newInstance; - (void)hello; @end
99. REPL and Playgrounds
100. REPL and Playgrounds • Interactive Coding • Immediate feedback
104. Demo Time
105. Much More
106. Much More • Ranges • Enums with values • Nested Functions • Default parameters • Variadic parameters • External and Internal names • Extensions • Type casting • Nested Types • Optional Chaining • ARC (Automatic Reference Counting) • @autoclosure • Namespaces
107. Final Word 2 - Java 3 - Objective-C 16 - Swift 40 - Scala Tiobe Index Fast - Faster than C Popular And trending 1,0 x 2,8 x 3,9 x Swift Objective-C Python
108. Konstantin Koval @KostiaKoval konstantinkoval.github.io Thanks