import UIKit @main class AppDelegate: UIResponder, UIApplicationDelegate { var window: UIWindow? } extension AppDelegate { func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { window = UIWindow(frame: UIScreen.main.bounds) window?.rootViewController = Main.Core() window?.makeKeyAndVisible() return true } }