code: public DTMIterator asIterator(
            XPathContext xctxt, int contextNode)
              throws javax.xml.transform.TransformerException
    {
      XNodeSet iter = new XNodeSet((LocPathIterator)m_clones.getInstance());
  
      iter.setRoot(contextNode, xctxt);
  
      return iter;
    }
docs: Given an select expression and a context, evaluate the XPath
  and return the resulting iterator.
  
  @param xctxt The execution context.
  @param contextNode The node that "." expresses.
  @throws TransformerException thrown if the active ProblemListener decides
  the error condition is severe enough to halt processing.
  
  @throws javax.xml.transform.TransformerException
  @xsl.usage experimental