Swift3 samples

Swift/SwiftClosures.playground/Pages/Autoclosure.xcplaygroundpage/Contents.swift

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+//: [Escaping closure](@previous)
+
+struct Test {
+    init() {
+        print("Test initialized")
+    }
+}
+
+func testFunc(isEnabled: Bool, closure: @autoclosure () -> Test) {
+    if isEnabled {
+        closure()
+    }
+}
+
+testFunc(isEnabled: true, closure: Test())
+testFunc(isEnabled: false, closure: Test())

Swift/SwiftClosures.playground/Pages/Escaping.xcplaygroundpage/Contents.swift

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+//: [Closure as function parameter](@previous)
+
+import Foundation
+
+struct FunctionStorage {
+
+    typealias ClosureType = (Int, Int) -> Int
+
+    private(set) var funcList: [ClosureType] = []
+
+    mutating func append(aFunction: @escaping ClosureType) {
+        funcList.append(aFunction)
+    }
+
+/*: ### The functions append() accepts and adds to the array a closure declared outside the function. */
+
+    mutating func append(functions: @escaping ClosureType...) {
+        funcList.append(contentsOf: functions)
+    }
+
+    func apply(to value: Int,
+               and aValue: Int,
+               from initial: Int = 0, with action: ClosureType) -> Int {
+
+        return funcList.reduce(initial) { (res, fn) -> Int in
+            action(res, fn(value, aValue))
+        }
+    }
+}
+
+var storage = FunctionStorage()
+storage.append(functions: (*), (+), (-))
+storage.apply(to: 4, and: 2, with: (+))
+
+
+/*: ### Default closure type is @noescape */
+
+//: [Autoclosure](@next)
+
+
+

Swift/SwiftClosures.playground/Pages/In function.xcplaygroundpage/Contents.swift

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+//: [Simple closure](@previous)
+
+func repeatFunc(num: Int, f: () -> ()) {
+    for _ in 1...num {
+        f()
+    }
+}
+repeatFunc(num: 5) {
+    print("Hello world")
+}
+
+
+
+var square: (Int) -> (Int) = { x in
+    return x * x
+}
+
+let myArray = [0,1,2,3,4]
+func through(array arr: [Int], f: (Int) -> (Int)) -> [Int] {
+    var result: [Int] = []
+    for i in arr {
+        result.append(f(i))
+    }
+    return result
+}
+
+
+let result = through(array: myArray) {
+    square($0)
+}
+
+
+//: [Escaping closure](@next)
+
+

Swift/SwiftClosures.playground/Pages/Simple.xcplaygroundpage/Contents.swift

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+var hiThere: () -> (String) = {
+    return "Hi there!"
+}
+hiThere()
+
+
+var square: (Int) -> (Int) = { x in
+    return x * x
+}
+
+/*: ###
+ Without explicitly declaring "x", you can use $0 as parameter:
+ */
+var squareAgain: (Int) -> (Int) = {
+    $0 * $0
+}
+square(10)
+
+var newSquare = square
+
+newSquare(5)
+
+//: [Closure as function parameter](@next)

Swift/SwiftClosures.playground/contents.xcplayground

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='6.0' target-platform='macos' display-mode='raw'>
+    <pages>
+        <page name='Simple'/>
+        <page name='In function'/>
+        <page name='Escaping'/>
+        <page name='Autoclosure'/>
+    </pages>
+</playground>