// magic functions to get the CoreData context and entity's instance
let context = getContext()
let entity = getEntity()

// nil out the binary blob, so CoreData erases the file in _EXTERNAL_DATA
entity.setValue(nil, forKey: "image")
context.save()

// then actually save your new blob
entity.setValue(blob, forKey: "image")
context.save()

internal var selectedIndex: AnyObject! {
    didSet {
        let oldIndex = oldValue as? Int
        let newIndex = selectedIndex as? Int
        print("selectedIndex didSet, old: \(oldIndex), new: \(newIndex)")
    }
}

popUpButton.selectItem(at: 2)

window.collectionBehavior.remove(.fullScreenPrimary)
window.collectionBehavior.insert(.fullScreenAuxiliary)

public extension FileManager {
  public func foo() throws -> URLRelationship {
    return URLRelationship.other
  }
}

public extension FileManager {
  public func foo() -> URLRelationship {
    return URLRelationship.other
  }
}

let reversed = names.sorted(by: { 
    (s1: String, s2: String) -> Bool in 
    return s1 > s2 
})

let reversed = names.sorted(by: >)

// singleton event system 
public static class EventSystem
{
  public static IEventAggregator Instance
  {
    get
    {
      // ?? operator, return left if not null, otherwise, return right
      return m_Instance ?? (m_Instance = new EventAggregator());
    }
  }
  private static IEventAggregator m_Instance;
}

public class ApplicationExitEvent : PubSubEvent<int>
{
}

token = 
EventSystem.Instance.GetEvent<ApplicationExitEvent>().Subscribe(
  OnApplicationExit, 
  ThreadOption.PublisherThread
  );

protected override void OnExit(ExitEventArgs e)
{
  // broadcast that we're exiting
  EventSystem.Instance.GetEvent<ApplicationExitEvent>().Publish(e.ApplicationExitCode);
}