class xxxxx: SKScene {

let rightSwipeRecognizer = UISwipeGestureRecognizer()
let leftSwipeRecognizer = UISwipeGestureRecognizer()
let upSwipeRecognizer = UISwipeGestureRecognizer()
let downSwipeRecognizer = UISwipeGestureRecognizer()

var swipeRecognizers: [UISwipeGestureRecognizer] {
    return [rightSwipeRecognizer, leftSwipeRecognizer, upSwipeRecognizer, downSwipeRecognizer]
}

var directionForRecognizer: [UISwipeGestureRecognizer : UISwipeGestureRecognizerDirection] {
    return [
        rightSwipeRecognizer : .right,
        leftSwipeRecognizer : .left,
        upSwipeRecognizer : .up,
        downSwipeRecognizer : .down
    ]
}

func didSwipeRight() {}
func didSwipeLeft() {}
func didSwipeUp() {}
func didSwipeDown() {}

var functionForRecognizer: [UISwipeGestureRecognizer : ()] {
    return [
        rightSwipeRecognizer : didSwipeRight(),
        leftSwipeRecognizer : didSwipeLeft(),
        upSwipeRecognizer : didSwipeUp(),
        downSwipeRecognizer : didSwipeDown()
    ]
}

func setupSwipeRecognizers() {
    for recognizer in swipeRecognizers {
        recognizer.addTarget(self, action: #selector(functionForRecognizer[recognizer]!))
        recognizer.direction = directionForRecognizer[recognizer]!
        self.view?.addGestureRecognizer(recognizer)
    }
}

override func didMove(to view: SKView) {
    super.didMove(to: view)
    setupSwipeRecognizers()
}

@objc // This annotation isn't required in Swift 3, but will be in Swift 4
func didSwipeRight() {}

var functionForRecognizer: [UISwipeGestureRecognizer : Selector] {
    return [
        rightSwipeRecognizer : #selector(didSwipeRight)
    ]
}

recognizer.addTarget(self, action: functionForRecognizer[recognizer]))