Um aplicativo iOS mínimo escrito em Swift

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: NSDictionary?) -> Bool {
self.window = UIWindow(frame: UIScreen.mainScreen().bounds)

var controller = UIViewController()
var view = UIView(frame: CGRectMake(0, 0, 320, 568))
view
.backgroundColor = UIColor.redColor()
controller
.view = view

var label = UILabel(frame: CGRectMake(0, 0, 200, 21))
label
.center = CGPointMake(160, 284)
label
.textAlignment = NSTextAlignment.Center
label
.text = "I'am a test label"
controller
.view.addSubview(label)

self.window!.rootViewController = controller
self.window!.makeKeyAndVisible()
return true
}