title: Ant: Two questions about dirsets
body: <p>I have two questions about the <a href="http://ant.apache.org/manual/Types/dirset.html" rel="nofollow">dirset type</a> in Apache Ant.</p>
  
  <ul>
  <li>Is a dirset really a set, with no order guaranteed, or does it preserves the input order?
  I want to use ant:contrib to iterate over a set of directories and order matters, so if Ant's dirset does not preserve insertion-order, what alternatives do I have?</li>
  <li>How can I test if a certain dir is included within a dirset?</li>
  </ul>