/* Returns a Value from this Enumeration whose name matches the argument <var>s</var>.
   * You must pass a String* set of names to the constructor,
   * or initialize each Enumeration with Value(String),
   * for valueOf to work.
   * @param s an enumeration name
   * @return <tt>Some(Value)</tt> if an enumeration's name matches <var>s</var>, 
   * else <tt>None</tt>
   */
  def valueOf(s:String) = {
    var v: Option[Value] = None
    for( e <- elements ) if (s == e.toString()) v = Some(e)
    v
  }