This document contains a summary of a Swift school presentation. It discusses introducing Objective-C and Swift, benefits of Swift like multiple returns, optionals for safety, and powerful enums. It also provides code examples of Swift features like variables, constants, optional handling, switches, loops, functions, classes, protocols, and bridging Objective-C and Swift.

1. Swift Школа
Сергей Пронин
Empatika

2. План
• Интро
• Why Swift?
• Как подружить Objective-C и Swift?

3. Интро
Сергей Пронин
Ведущий разработчик Empatika
Ведущий разработчик App in the Air
Преподаватель НИУ-ВШЭ
@spronin
sergey@pronin.me

4. Why Swift?
• Multiple return values
• Optionals -> Safety
• Playgrounds
• Extensions
• Powerful enums
• Sweet syntax

5. var variable: Double = 55
variable = 12
let constant = 42 //implicit Int
let str = "Answer is (constant)"
var ar: [Int] = [1, 2, 3]
var dic: [String: AnyObject] = ["key": "value",
"num": 123]
for n in ar {
if n % 2 == 0 {
println(n)
}
}
for (key, value) in dic {
println("(key) -> (value)")
}

6. var optional: String? = "Hello?"
if let exists = optional {
println(exists)
}
if optional != nil {
println(optional!)
}
if optional?.hasSuffix("?") {
println("somebody home?")
}

7. let lang = "swift"
switch (lang) {
case "swift":
println("young")
case let x where x.hasSuffix("#"):
println("wat?")
case "js", "css":
println("web")
default:
println("java, is it you?")
}
//add <break> to exit clause
//add <fallthrough> to fall through

8. for i in 0..<ar.count { //0...n = [0,n]
println(ar[i])
}
for var i = 0; i < ar.count; i++ {
println(ar[i])
}
do {
fetchMessagesFromServer()
sleep(5)
} while true
while ar.count > 0 {
ar.removeLast()
}

9. func confession(name: String) -> String {
return "I miss (name)"
}
confession("my mom")
func fl(a: [AnyObject]) ->
(first: AnyObject, last: AnyObject) {
return (a[0], a[a.count-1])
}
var result = fl(ar)
println(result.first)
println(result.1)

10. func params(numbers: Int…) -> Int {
var sum = 0
for n in numbers {
sum += n
}
return sum
}
params(1, 1, 2, 3, 5, 8)

11. func isEven(n: Int) -> Bool {
return n % 2 == 0
}
func filter(a: [Int], check: Int -> Bool)
-> [Int] {
var result: [Int] = []
for n in a {
if check(n) {
result.append(n)
}
}
return result
}
filter(0...10, isEven)

12. filter(0...10, { (item: Int) -> Bool in
return item % 2 == 0
})
filter(0...100, { item in item % 10 == 0 })
filter(0...100, { $0 % 10 == 0 })
filter(0...100) { $0 % 10 == 0 }

13. class Shape {
var sides = 0
var name: String
init(name: String) {
self.name = name
}
func description() -> String {
return "Sides -> (sides)"
}
}
var shape = Shape(name: "ama shape")
shape.description()

14. class Triangle: Shape {
var a, b, c: Int
init(name: String, sides a: Int, _ b: Int, _ c: Int) {
self.a = a
self.b = b
self.c = c
super.init(name: name)
self.sides = 3
}
var perimeter: Int {
get {
return a + b + c
}
}
override func description() -> String {
return "Triangle with perimeter -> (perimeter)"
}
}
var tr = Triangle(name: "Tr", sides: 5, 10, 20)
tr.description

15. extension Shape {
class func plusFunction() -> String {
return "I’m a class function "
}
}
Shape.plusFunction()
struct StructShape {
//all the same code, actually
static func plusFunction() -> String {
return "Passed by value"
}
}
//struct objects are being passed by value
//class objects are being passed by reference

16. enum Status: Int {
case Undetermined, Success, Failure
}
func sendRequest() -> Status {
//networking magic
return Status.Success
}
var result = sendRequest()
switch result {
case .Success:
println("success")
case .Failure:
println("failure")
case .Undetermined:
println("n/a")
}
result = Status.fromRaw(1)! //Success
result.toRaw() //1

17. protocol NetworkingDelegate {
func request(request: NSURLRequest,
completedWithResult result: NSData?)
}
class ServerHelper {
var delegate: NetworkingDelegate?
func doRequest(request: NSURLRequest) {
var data = NSData(contentsOfURL: request.URL)
delegate?.request(request, completedWithResult: data)
}
}
class Controller: NetworkingDelegate {
func request(request: NSURLRequest,
completedWithResult result: NSData?) {
println("magic")
}
let helper = ServerHelper()
helper.delegate = Controller()
let url = NSURL(string: "http://empatika.com")
helper.doRequest(NSURLRequest(URL: url)))

18. Objective-C + Swift

19. Готовимся
typedef enum {
StatusSuccess, StatusFailure
} Status
typedef NS_ENUM(NSInteger, Status) {
StatusSuccess, StatusFailure
};

20. + (id)sharedInstance {
//your singleton magic
}
+ (instancetype)sharedInstance {
//singleton magic
}
- (instancetype)init {
//initial magic
}

21. • В существующей Objective-C codebase ->
New File - Cocoa Touch Class -> Swift ->
Configure Header
• В созданный Bridging Header импортируем все,
что Swift должен видеть из Obj-C
#import “MyAFAPIClient.h”
• Чтобы Obj-C видел из Swift импортируем
#import “ProductModuleName-Swift.h”
• Открыть Swift-классы и протоколы через @objc
@objc(Venue)
class Venue {…}

22. Перегнать модель или
Controller на Swift
Начать новый проект на
Swift с модели или
Controller-а