http://atnd.org/events/53235 Swift勉強会(STULIO×Phybbit)@21Cafe 2014/07/09 で発表した内容になります。

1. SWIFT
2014.7.9
bOb_sTrane@Phybbit
/ /twitter github Qiita

2. Swift
Swift

3. @bOb_sTrane(Qiita/Twitter)
Phybbit iOS /Rails
( ...) , FRP
(Lisp Scala Haskell )

4. SWIFT

5. SWIFT
1.
2.
3.
4.

6. // Intの引数2つを取り、和を返す関数
func add(a: Int, b: Int) -> Int{
return a + b
}
// Intの引数2つを取りIntを返す関数型を引数する関数
func someFunc(mathFunction: (Int, Int) -> Int, a: Int, b: Int) {
println(mathFunction(a, b))
}
someFunc(add, 100, 200) // 300が出力

7. func stepForward(input: Int) -> Int {
return input + 1
}
func stepBackward(input: Int) -> Int {
return input - 1
}
func chooseStepFunction(isBackward: Bool) -> (Int) -> Int {
return isBackward ? stepBackward : stepForward
}
var currVal = 10
let moveNearerToZero = chooseStepFunction(currVal > 0)
while currVal != 0 {
currVal = moveNearerToZero(currVal)
println(currVal) // 0まで1ずつカウントダウン
}

8. // 普通に定義
func greeting(name: String) {
println("Hello (name)")
}
greeting("Taro")
// 関数を変数に代入して定義
let greeting = { (name:String) -> Void in
println("Hello (name)")
}
greeting("Taro")

9. func chooseStepFunction(isBackward: Bool) -> (Int) -> Int {
// 関数内で関数を宣言
func stepForward(input: Int) -> Int { return input + 1 }
func stepBackward(input:Int) -> Int { return input - 1 }
return isBackward ? stepBackward : stepForward
}
var currentValue = -4
let moveNearerToZero = chooseStepFunction(currentValue > 0)
while currentValue != 0 {
currentValue = moveNearerToZero(currentValue)
println(currentValue)
}
// while currentValue != 0 {
// stepForwardがスコープ外のため実行できない
// currentValue = stepForward(currentValue)
// }

10. let names = ["Taro", "Jiro", "Saburo", "Shiro", "Goro"]
// 通常の定義方法
sorted(names) {(s1:String, s2:String) -> Bool in return s1 > s2 }
// [Taro, Shiro, Saburo, Jiro, Goro]
// 型推論 (sorted関数の定義から推論される)
sorted(names) { s1, s2 in return s1 > s2}
// 引数名の自動生成 & 暗示的なreturn
sorted(names) { $0 > $1 }

11. (Blocks )
class LeakPerson {
var name: String
@lazy var greeting: String = { return "Hello, (self.name)" }()
init(name: String) { self.name = name }
deinit { println("LeakPerson deinit called") }
}
var leakPerson: LeakPerson! = LeakPerson(name:"Leak")
println(leakPerson.greeting)
leakPerson = nil // deinitがコールされない

12. class Person {
var name: String
@lazy var greeting: String = { [unowned self] in return "Hello, (self.name)" }()
init(name: String) { self.name = name }
deinit { println("Person deinit called") }
}
var person: Person! = Person(name:"NotLeak")
println(person.greeting)
person = nil // deinitがコールされる

13. SWIFT

14. SWIFT
@lazy

15. class Person {
var name: String
@lazy var personalizedGreeting: String = {
[unowned self] in
println("heavy task started")
// Something very heavy task
for value in 0...20000000 {
if value > 10000000 && value % 100000 == 0{
println("value is (value)")
}
}
println("personalizedGreeting called")
return "Hello, (self.name)!"
}()

16. ( )
init (name:String) {
self.name = name
println("initialized")
}
deinit {
println("destructed")
}
}
var person: Person! = Person(name: "Strange Bob")
println("person object has initialized")
println(person.personalizedGreeting)
person = nil
personalizedGreeting

17. Blocks
lazy

18. Swift
Swift --
Swift @lazy
How to do proper LazyLoadingin Swift
Learn SwiftbyrunningScripts
MemoryLeaks In The SwiftPlayground
LazyInitialization with Swift

20. 7 1 otakyou.com
( )https://www.otakyou.com/