title: NSIndexPath incrementing values
body: <p>I am trying to populate an OutlineView with the contents of a XML file.</p>
  
  <p>I'd like to create and manage the values inside a NSIndexPath while cocoa parses the document.
  NSIndexPath has methods to add and remove indexes, but I need to increment/decrement the values in each index:</p>
  
  <p>[0, 0]<br/>
  [0, 1]<br/>
  [0, 2]<br/></p>
  
  <p>and so on...</p>
  
  <p>how can I do that?</p>