title: Can I override func mouseDown Without Subclassing?
body: <p>Can I override func mouseDown only for a specific instance of NSView without subclassing?</p>
  
  <p>I can do something like this using lambda in Java (see below), but can I do something like this using closure in Swift?</p>
  
  <pre><code>something.addMouseListener(new MouseAdapter() {
      @Override public void mouseReleased(MouseEvent e) {
          ...
      }
  
      @Override public void mousePressed(MouseEvent e) {
          ...
      }
  });
  </code></pre>