先ほどの自分の発表で使ったコード、とは若干違うところもありますけど、とりあえず資料を書きながら作ったコードを切り出しました。 #__swift__ #CodePiece

CodePiece.swift

protocol Movable {
    
    associatedtype Unit
    
    func moved(x x:Unit, y:Unit) -> Self
    func movedHorizontal(x:Unit) -> Self
    func movedVertical(y:Unit) -> Self
}

struct Location {

    var x: Int
    var y: Int
}

extension Location : Movable {
    
    typealias Unit = Int
    
    func moved(x x:Int, y:Int) -> Location {
        return movedHorizontal(x).movedVertical(y)
    }
    
    func movedHorizontal(x:Int) -> Location {
        return Location(x: self.x + x, y: self.y)
    }
    
    func movedVertical(y:Int) -> Location {
        return Location(x: self.x, y: self.y + y)
    }
}

extension Location : CollectionType {
    
    var startIndex: Int {
        
        return 0
    }
    
    var endIndex: Int {
        
        return 2
    }

    subscript (index: Int) -> Int {

        switch index {
            
        case 0:
            return x
            
        case 1:
            return y
            
        default:
            fatalError()
        }
    }
}

let location = Location(x: 10, y: 20)

let newLocation1 = location.movedHorizontal(10)
let newLocation2 = newLocation1.movedVertical(20)
let newLocation3 = newLocation1.moved(x: 4, y: 8)

location.count      // 2
location.indices    // 0 ..< 2
location.first!     // x
location.last!      // y
location.minElement()
location.maxElement()

for v in location {
    
    print(v)
}

import Darwin

print(location.map { $0 * 2 })

func randomMove<T:Movable where T.Unit == Int>(location: T, maxStep: T.Unit) -> T {
    
    let deltaX = Int(arc4random_uniform(UInt32(maxStep)))
    let deltaY = Int(arc4random_uniform(UInt32(maxStep)))
    
    return location.moved(x: deltaX, y: deltaY)
}

randomMove(location, maxStep: 100)

import Cocoa
import AVFoundation

protocol MediaType {
    
    var data: NSData { get }
}


protocol PlayerType {
    
    var content: Music? { get }
//    var canPlay: Bool { get }
    func play() throws
}

enum PlayerError : ErrorType {
    
    case NotReady
}

struct Music : MediaType {
    
    init(_ name: String) {
        
    }
    
    var data: NSData {
        
        return NSData()
    }
}

struct NullSound : MediaType {
	
	var data: NSData {
		
		return NSData()
	}
}

class AVAudioPlayerEx : AVAudioPlayer {

	override init(data: NSData) throws {
		
		super.init()
	}
}

extension PlayerType {
    
    var canPlay: Bool {
        
        return content != nil
    }
    
    func play() throws {
        
        guard canPlay else {
            
            throw PlayerError.NotReady
        }
		
		try AVAudioPlayerEx(data: content?.data ?? NullSound().data)
    }

}

final class MusicPlayer : PlayerType {
    
    var content: Music?
    
    init(content: Music?) {
    
        self.content = content
    }
}

final class SilentSoundPlayer : PlayerType {
	
	let content: Music? = nil
	
	var canPlay: Bool {
		
		return true
	}

//	func play() throws {
//		
//		guard canPlay else {
//			
//			throw PlayerError.NotReady
//		}
//		
//		try AVAudioPlayerEx(data: NullSound().data)
//	}
}

let player1 = MusicPlayer(content: Music("SomeSound.mp3"))
let player2 = SilentSoundPlayer()
let player3: PlayerType = SilentSoundPlayer()


if player1.canPlay {
	
	do {
    try player1.play()
	print("YES")
	}
	catch { print("ERROR: \(error)") }
}
else {
	print("NO")
}

if player2.canPlay {
	
	do {
	try player2.play()
		print("YES")
	}
	catch { print("ERROR: \(error)") }
}
else {
	print("NO")
}

if player3.canPlay {
	
	do {
		try player3.play()
		print("YES")
	}
	catch { print("ERROR: \(error)") }
}
else {
	print("NO")
}
func start<T:PlayerType>(player: T) throws -> Bool {

	if player.canPlay {

		try player.play()
		return true
	}
	else {
		
		return false
	}
}

player1.canPlay
player2.canPlay
player3.canPlay

try? start(player1)		// true
try? start(player2)		// true
//try? start(player3)

protocol Walkable {
    
    func walk() -> String
}

extension Walkable {

    func walk() -> String {
        
        return "By Spilit"
    }
}

class Human : Walkable {
    
    func walk() -> String {
        
        return "By Human"
    }
}

let human: Walkable = Human()

human.walk()