Notes from Introduction to Swift - WWDC 2014

basics.swift

#!/usr/bin/env xcrun swift -i
//No, it doesn't compile


//Hello World
println("Hello Worl")

//Variables 
var aInt: Int = 1

//Constants 
let myName: String = "Andre Oriani"
let isDeveloper: Bool = true
let pi: Double = 3.14
let letter: Character = "A"


//Infered types 
let maxSize = 3

//Like python you loop on string chars
for character in "word" {
	println(character)
}

//Concatenating chars
let a: Character = "a"
let b: Character = "b"
let ab: String = a + b

//String Interpolation
let a = 3, b = 5
let mathResult = "\(a) times \(b) equal \(a * b)"

//Concatenating strings
let aString = "Part 1"
let theString += " Introduction"

//Arrays and dictonaries
var names = ["a", "b", "c"]
var ponts = ["a": 1, "b": 10, "c": 20]

//Loops
while !ready {
	doIt()
}

for var i = 0;  i < 7; i++ {
	println(i)
}

//Closed end
for i in 0...6 {

}

//Open end
for i in 0..5 {

}

//Dictionaries
for (key, value) in dict {

}

//Array append
var inteiros = [1, 2, 3]
inteiros += 4
//Array update
inteiros[0] = 0
//Ranged replacement
inteiros [0...3] = [10, 20, 30, 40]

//dictionary
//Adding new key
var dict = ["a": 1, "b": 2]
dict["c"] = 3

//Optional
let num:Int? = dict["invalidKey"]
if num == nil {
	println("not found")
} else {
	let numero = num!
	println("num is \(numero)")
}

if num {
	let numero = num!
	println("num is \(numero)")
}

if let numero = num {
	println("num is \(numero)")
}

//Conditionals 
if a == 0 {

} else if b == 1 {

} else {
	
}

switch value {
	case 0,1:

	case 2...9:

	default:
}

// Functions
func Hello(name: String = "Default Value") -> String {
	return "Hello " + name
}

//Tuples 
func tuples () -> (Int, String) {
	return (200, "Success")
}

//Named values in tuple 
func tuples2 () -> (code: Int, message: String) {
	return (200, "Success")
}

let status = tuples2()
println("code: \(status.code)")

//Closures
let helloWorld: () -> () = {
	println("helloWorld")
}

let helloWorld = {
	println("helloWorld")
}

func repeatableTask(count: Int, task: () -> () ) {
	for i in 0..count {
		task()
	}
}

repeatableTask(2, {
		println("hi")
	})

//If the closure is the last arg there's special syntax
repeatableTask(2) {
	println("hi")
}

//Classes
class Klazz {

}

class SubClass: SuperClass {

}

//Properties
class Vehicle {
	//Stored
	var numberOfWheels = 0
	//Computed r/w
	var desc: String {
		get {
			return "\(numberOfWheels) whells"
		}

		set {
			//Well do something
		}
	}

	//Computed read only 
	var voila: String {
		return "Voilá"
	}
}

let car = Vehicle()
println(car.desc)

class Bike: Vehicle {
	init() {
		super.init()
		numberOfWheels = 2
	}

	override var desc: String {
		return super.desc + " haha"
	}
}


//Property Observersers
class ParentsCar: Car {
	override var speed: Double {
		willSet {
			//newValue 
			if newValue > 65.0 {
				println("Careful!")
			}
		}

		didSet {
			//oldValue
		}
	}
}

//Methods 
class Counter {
	var count = 0;
	func increment() {
		count++
	}
}

class Counter2 {
	var count = 0;
	func increment(count: Int) {
		self.count += count
	}
}

//struct
struct Point {
	var x,y: Double
}

struct Rect {
	var topLeft, bottomRigh: Point

	var area: Double {
		get {
			return topLeft.x * bottomRigh.y
		}
	}

	func area() -> Double {
		return topLeft.x * bottomRigh.y
	}
}

var point = Point(x:1.0, y:2.0)
// structs cannot inherit from other structs
// structs are passed by value (cpy) and class' objects by value

let a: StructType = StructType() // Imutable  like  C++ const Point a = {x:1, y:2};

struct name {
	var x, y : Int

	mutating func offsetBy(dx:Int, dy:Int) { //close C++ mutable 
		x += dx
		y += dy
	}
}

// BTW, newer  Swift uses print instead of println

//enums
enum Status: Int {
	case Failure = 0, Success, Unknown	
}

let success = Status.Success.toRaw() // success == 1

enum SpecialChars: Character {
	case Tab = "\t"
	case LineFeed = "\n"
}

enum Direction {
	case North, South, East, West
}

var direction = Direction.North
direction = .South

//Associate value
enum TrainStatus {
	case OnTime
	case Delayed(Int)

	init() {
		self = OnTime
	}	

	var desc: String {
		switch self {
			case OnTime:
				return "on time"
			case Delayed(let minutes): {
				return "delayed \(minutes) min"
			}
		}
	}
}

var status = TrainStatus()
status = .Delayed(5)

//Extensions
extension Int {
	func repetitions(task: () -> ()) {
		for in in 0..self {
			task;
		}
	}
}

//Say one milion times sorry
10000000.repetitions {
	print("Sorry\n")
}

//Generics
struct Stack<T> {
	var elements = T[]()

	mutating func push(element: T) {
		element.append(element)
	}

	mutating func pop() -> T {
		return elements.removeLast()
	}
}

var stack = Stack<Int>()
stack.push(56)