/**
 * Standard queues.  Things get added to the end and removed from the
 * front.
 */
public interface Queue
  extends Linear
{
  // +--------------------------------------------------
  // | Design notes |
  // +---+

  /*
     Yes, this interface is empty.  Queues have no operations
     that linear structures lack.  The only thing they add
     is a presumption about what delete does.
   */
} // inteface Queue