code: public XObject execute(XPathContext xctxt, int context)
            throws javax.xml.transform.TransformerException
    {
  
      DTMIterator nl = m_functionExpr.asIterator(xctxt, context);
      XNumber score = SCORE_NONE;
  
      if (null != nl)
      {
        int n;
  
        while (DTM.NULL != (n = nl.nextNode()))
        {
          score = (n == context) ? SCORE_OTHER : SCORE_NONE;
  
          if (score == SCORE_OTHER)
          {
            context = n;
  
            break;
          }
        }
  
        // nl.detach();
      }
      nl.detach();
  
      return score;
    }
docs: Test a node to see if it matches the given node test.
  
  @param xctxt XPath runtime context.
  
  @return {@link org.apache.xpath.patterns.NodeTest#SCORE_NODETEST},
  {@link org.apache.xpath.patterns.NodeTest#SCORE_NONE},
  {@link org.apache.xpath.patterns.NodeTest#SCORE_NSWILD},
  {@link org.apache.xpath.patterns.NodeTest#SCORE_QNAME}, or
  {@link org.apache.xpath.patterns.NodeTest#SCORE_OTHER}.
  
  @throws javax.xml.transform.TransformerException