c3a0009.a

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-- C3A0009.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 subprogram references may be passed as parameters using 
--      access-to-subprogram types. Check that the passed subprograms may 
--      be invoked from within the called subprogram.
--
-- TEST DESCRIPTION:
--      Declare an access to procedure type in a package specification. 
--      Declare a root tagged type with the access to procedure type as a 
--      component.  Declare three primitive procedures for the type that 
--      can be referred to by the access to procedure type.  Use the access 
--      to procedure type to initialize the component of a record.
--
--      Extend the root type with a private extension in the same package
--      specification. Declare two new primitive subprograms for the extension
--      (in addition to its three inherited subprograms).
--
--      In the main program, declare an operation for the root tagged type 
--      which can be passed as an access value to change the initial value
--      of the component.  Call the inherited operations indirectly by 
--      de-referencing the access value to set value in the extension.
--      Call the primitive function to modify the extension by passing 
--      the access value designating the primitive procedure as a parameter.
--
--
-- CHANGE HISTORY:
--      06 Dec 94   SAIC    ACVC 2.0
--
--!

package C3A0009_0 is -- Push_Buttons

   type Button is tagged private;

   -- Type accesses to procedures Push and Default_Response
   type Button_Response_Ptr is access procedure
      (B : in out Button);

   procedure Push (B : in out Button);               -- to be inherited

   procedure Set_Response (B : in out Button;        -- to be inherited
                           R : in Button_Response_Ptr);

   procedure Default_Response  (B : in out Button);  -- to be inherited

   type Alert_Button is new Button with private;  -- private extension of
                                                  -- root tagged type
   -- Inherits procedure Push from Button
   -- Inherits procedure Set_Response from Button
   -- Inherits procedure Default_Response from Button

   procedure Replace_Action( B: in out Alert_Button );

   -- type accesses to procedure Default_Action
   type Button_Action_Ptr is access procedure;

   -- The following function is needed to set value in the
   -- extension's private component.
   function Alert (B : in Alert_Button) return Button_Action_Ptr;

private

   type Button is tagged                             -- root tagged type
      record
         Response :  Button_Response_Ptr 
                  := Default_Response'Access;   
      end record;

   procedure Default_Action;

   type Alert_Button is new Button with record
        Action :  Button_Action_Ptr 
               := Default_Action'Access;
      end record;

end C3A0009_0;


-----------------------------------------------------------------------------


with TCTouch;
package body C3A0009_0 is

   procedure Push (B : in out Button) is
   begin
      TCTouch.Touch( 'P' ); --------------------------------------------- P
      -- Invoking subprogram designated by access value
      B.Response (B);
   end Push;


   procedure Set_Response (B : in out Button;
                           R : in     Button_Response_Ptr) is
   begin
      TCTouch.Touch( 'S' ); --------------------------------------------- S
      -- Set procedure value in record
      B.Response := R;
   end Set_Response;


   procedure Default_Response (B : in out Button) is
   begin
      TCTouch.Touch( 'D' ); --------------------------------------------- D
   end Default_Response;


   procedure Default_Action is
   begin
      TCTouch.Touch( 'd' ); --------------------------------------------- d
   end Default_Action;

   procedure Replacement_Action is
   begin
      TCTouch.Touch( 'r' ); --------------------------------------------- r
   end Replacement_Action;

   procedure Replace_Action( B: in out Alert_Button ) is
   begin
      TCTouch.Touch( 'R' ); --------------------------------------------- R
      B.Action := Replacement_Action'Access;
   end Replace_Action;

   function Alert (B : in Alert_Button) return Button_Action_Ptr is
   begin
      TCTouch.Touch( 'A' ); --------------------------------------------- A
      return (B.Action);
   end Alert;

end C3A0009_0;

-----------------------------------------------------------------------------

with C3A0009_0;
package C3A0009_1 is -- Emergency_Items
   package Push_Buttons renames C3A0009_0;

   procedure Emergency (B : in out Push_Buttons.Button);
end C3A0009_1;

with TCTouch;
package body C3A0009_1 is -- Emergency_Items
   procedure Emergency (B : in out Push_Buttons.Button) is
      begin
        TCTouch.Touch( 'E' ); ------------------------------------------- E
      end Emergency;
end C3A0009_1;
-----------------------------------------------------------------------------

with Report;

with C3A0009_0, C3A0009_1; 
with TCTouch;
procedure C3A0009 is

   package Push_Buttons    renames C3A0009_0;
   package Emergency_Items renames C3A0009_1;
      
   Black_Button : Push_Buttons.Alert_Button;
   Alert_Ptr    : Push_Buttons.Button_Action_Ptr;

begin

   Report.Test ("C3A0009", "Check that subprogram references may be passed "
                         & "as parameters using access-to-subprogram types. "
                         & "Check that the passed subprograms may be "
                         & "invoked from within the called subprogram");


   Push_Buttons.Push( Black_Button );
   Push_Buttons.Alert( Black_Button ).all;

   TCTouch.Validate( "PDAd", "Default operation set" );

   -- Call inherited operations Set_Response and Push to set 
   -- Emergency value in the extension.
   Push_Buttons.Set_Response (Black_Button, Emergency_Items.Emergency'Access);
 

   Push_Buttons.Push( Black_Button );
   Push_Buttons.Alert( Black_Button ).all;

   TCTouch.Validate( "SPEAd", "Altered Response set" );

   -- Call primitive operation to set action value in the extension.
   Push_Buttons.Replace_Action( Black_Button );


   Push_Buttons.Push( Black_Button );
   Push_Buttons.Alert( Black_Button ).all;

   TCTouch.Validate( "RPEAr", "Altered Action set" );

   Report.Result;
end C3A0009;