code: protected int _exptype(int identity)
    {
    	if (identity == DTM.NULL)
    	return NULL;
      // Reorganized test and loop into single flow
      // Tiny performance improvement, saves a few bytes of code, clearer.
      // %OPT% Other internal getters could be treated simliarly
      while (identity>=m_size)
      {
        if (!nextNode() && identity >= m_size)
          return NULL;
      }
      return m_exptype.elementAt(identity);
  
    }
docs: Get the expanded type ID for the given node identity.
  
  @param identity The node identity.
  
  @return The expanded type ID, or DTM.NULL.