store-init.swift

class AppDelegate: UIResponder, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        // Initialize store
        let context: NSManagedObjectContext = ...
        let store = EventStore(context: context)

        // Initialize root view controller
        let viewController = EventListTableViewController(store: store)

        // Initialize window...
    }
}

class AddEventViewController: UIViewController {
    private let store: EventStore

    init(store: EventStore) {
        self.store = store
        super.init(nibName: nil, bundle: nil)
    }

    func addEventButtonTapped() {
        let event = Event()
        event.title = "I went to the hairdresser"
        event.date = Date()

        store.insert(event)
    }
}