-- Code of Queues specification on page 391 from
-- Kenneth C. Louden, Programming Languages
-- Principles and Practice 2nd Edition
-- Copyright (C) Brooks-Cole/ITP, 2003
-- (Opaque static queue)

generic
  type T is private;
package Queues2 is
  procedure enqueue(elem:T);
  function frontq return T;
  procedure dequeue;
  function emptyq return Boolean;
end Queues2;