-- CA11020.A
--
-- Grant of Unlimited Rights
--
-- Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
-- F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained
-- unlimited rights in the software and documentation contained herein.
-- Unlimited rights are defined in DFAR 252.227-7013(a)(19). By making
-- this public release, the Government intends to confer upon all
-- recipients unlimited rights equal to those held by the Government.
-- These rights include rights to use, duplicate, release or disclose the
-- released technical data and computer software in whole or in part, in
-- any manner and for any purpose whatsoever, and to have or permit others
-- to do so.
--
-- DISCLAIMER
--
-- ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
-- DISCLOSED ARE AS IS. THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED
-- WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
-- SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE
-- OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
-- PARTICULAR PURPOSE OF SAID MATERIAL.
--*
--
-- OBJECTIVE:
-- Check that body of the generic parent package can depend on one of
-- its own public generic children.
--
-- TEST DESCRIPTION:
-- A scenario is created that demonstrates the potential of adding a
-- public generic child during code maintenance without distubing a large
-- subsystem. After child is added to the subsystem, a maintainer
-- decides to take advantage of the new functionality and rewrites
-- the parent's body.
--
-- Declare a bag abstraction in a generic package. Declare a public
-- generic child of this package which adds a generic procedure to the
-- original subsystem. In the parent body, instantiate the public
-- child. Then instantiate the procedure as a child instance of the
-- public child instance.
--
-- In the main program, declare an instance of parent. Check that the
-- operations in both parent and child packages perform as expected.
--
--
-- CHANGE HISTORY:
-- 06 Dec 94 SAIC ACVC 2.0
--
--!
-- Simulates bag application.
generic
type Element is private;
with function Image (E : Element) return String;
package CA11020_0 is
type Bag is limited private;
procedure Add (E : in Element; To_The_Bag : in out Bag);
function Bag_Image (B : Bag) return string;
private
type Node_Type;
type Bag is access Node_Type;
type Node_Type is
record
The_Element : Element;
-- Other components in real application, i.e.,
-- The_Count : positive;
Next : Bag;
end record;
end CA11020_0;
--==================================================================--
-- More operations on Bag.
generic
-- Parameters go here.
package CA11020_0.CA11020_1 is
-- ... Other declarations.
generic -- Generic iterator procedure.
with procedure Use_Element (E : in Element);
procedure Iterate (B : in Bag); -- Called once per element in the bag.
-- ... Various other operations.
end CA11020_0.CA11020_1;
--==================================================================--
package body CA11020_0.CA11020_1 is
procedure Iterate (B : in Bag) is
-- Traverse each element in the bag.
Elem : Bag := B;
begin
while Elem /= null loop
Use_Element (Elem.The_Element);
Elem := Elem.Next;
end loop;
end Iterate;
end CA11020_0.CA11020_1;
--==================================================================--
with CA11020_0.CA11020_1; -- Public generic child package.
package body CA11020_0 is
----------------------------------------------------
-- Parent's body depends on public generic child. --
----------------------------------------------------
-- Instantiate the public child.
package MS is new CA11020_1;
function Bag_Image (B : Bag) return string is
Buffer : String (1 .. 10_000);
Last : Integer := 0;
-----------------------------------------------------
-- Will be called by the iterator.
procedure Append_Image (E : in Element) is
Im : constant String := Image (E);
begin -- Append_Image
if Last /= 0 then -- Insert a comma.
Last := Last + 1;
Buffer (Last) := ',';
end if;
Buffer (Last + 1 .. Last + Im'Length) := Im;
Last := Last + Im'Length;
end Append_Image;
-----------------------------------------------------
-- Instantiate procedure Iterate as a child of instance MS.
procedure Append_All is new MS.Iterate (Use_Element => Append_Image);
begin -- Bag_Image
Append_All (B);
return Buffer (1 .. Last);
end Bag_Image;
-----------------------------------------------------
procedure Add (E : in Element; To_The_Bag : in out Bag) is
-- Not a real bag addition.
Index : Bag := To_The_Bag;
begin
-- ... Error-checking code omitted for brevity.
if Index = null then
To_The_Bag := new Node_Type' (The_Element => E,
Next => null);
else
-- Goto the end of the list.
while Index.Next /= null loop
Index := Index.Next;
end loop;
-- Add element to the end of the list.
Index.Next := new Node_Type' (The_Element => E,
Next => null);
end if;
end Add;
end CA11020_0;
--==================================================================--
with CA11020_0; -- Bag application.
with Report;
procedure CA11020 is
-- Instantiate the bag application for integer type and attribute
-- Image.
package Bag_Of_Integers is new CA11020_0 (Integer, Integer'Image);
My_Bag : Bag_Of_Integers.Bag;
begin
Report.Test ("CA11020", "Check that body of the generic parent package " &
"can depend on one of its own public generic children");
-- Add 10 consecutive integers to the bag.
for I in 1 .. 10 loop
Bag_Of_Integers.Add (I, My_Bag);
end loop;
if Bag_Of_Integers.Bag_Image (My_Bag)
/= " 1, 2, 3, 4, 5, 6, 7, 8, 9, 10" then
Report.Failed ("Incorrect results");
end if;
Report.Result;
end CA11020;