-- Polymorphic stack example (Stack User)
-- in Ada from page 249 of
-- Kenneth C. Louden, Programming Languages
-- Principles and Practice 2nd Edition
-- Copyright (C) Brooks-Cole/ITP, 2003

with Text_IO; use Text_IO;
with Ada.Integer_Text_IO;
use Ada.Integer_Text_IO;

with Stacks; -- import the Stacks package

procedure StackUsr is

package IntStacks is new Stacks(integer);
     -- instantiate the parameterized package 
     -- with type integer

use IntStacks;
   -- without this, we must write use the package name
   -- before all of its components, e.g. IntStacks.Stack,
   -- IntStacks.StackNode, IntStacks.pop, etc.

s: Stack := new StackNode;
t: integer;

begin
  s.data := 3;
  s.next := null;
  t := top(s); -- t is now 3
  put(t);
end StackUsr;