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-- CC30001.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 if a non-overriding primitive subprogram is declared for

--      a type derived from a formal derived tagged type, the copy of that

--      subprogram in an instance can override a subprogram inherited from the

--      actual type.

--

-- TEST DESCRIPTION:

--      User writes program to handle both mail messages and system messages.

--

--      Mail messages are created by instantiating a generic "mail" package

--      with a root message type. System messages are created by

--      instantiating the generic with a system message type derived from the

--      root in a separate package. The system message type has a primitive

--      subprogram called Send.

--

--      Inside the generic, a "mail" type is derived from the generic formal

--      derived type, and a "Send" operation is declared.

--

--      Declare a root tagged type T. Declare a generic package with a formal

--      derived type using the root tagged type as ancestor. In the generic,

--      derive a type from the formal derived type and declare a primitive

--      subprogram for it. In a separate package, declare a derivative DT of

--      the root tagged type T and declare a primitive subprogram which is

--      type conformant with (and hence, overridable for) the primitive

--      declared in the generic. Instantiate the generic for DT. Make both

--      dispatching and non-dispatching calls to the primitive subprogram. In

--      both cases the version of the subprogram in the instance should be

--      called (since it overrides the implementation inherited from the

--      actual).

--

--

-- CHANGE HISTORY:

--      06 Dec 94   SAIC    ACVC 2.0

--      13 Apr 95   SAIC    Replaced call involving instance for root tagged

--                          type with a dispatching call involving instance

--                          for derived type. Updated commentary. Moved

--                          instantiations (and related commentary) to

--                          library-level to avoid accessibility violation.

--                          Commented out instantiation for root tagged type.

--      27 Feb 97   PWB.CTA Added elaboration pragma.

--!

package CC30001_0 is  -- Root message type.

   type Msg_Type is tagged record

      Text         : String (1 .. 20);

      Message_Sent : Boolean;

   end record;

end CC30001_0;

     --==================================================================--

with CC30001_0;  -- Root message type.

generic          -- Generic "mail" package.

   type Message is new CC30001_0.Msg_Type with private;

package CC30001_1 is

   type Mail_Type is new Message with record   -- Derived from formal type.

      To : String (1 .. 8);

   end record;

   procedure Send (M : in out Mail_Type);      -- For this test, this version

                                               -- of Send should be called in

   -- ... Other operations.                    -- all cases.

end CC30001_1;

     --==================================================================--

package body CC30001_1 is

   procedure Send (M : in out Mail_Type) is

   begin

      -- ... Code to send message omitted for brevity.

      M.Message_Sent := True;

   end Send;

end CC30001_1;

     --==================================================================--

with CC30001_0;       -- Root message type.

package CC30001_2 is  -- System message type and operations.

   type Signal_Type is (Note, Warning, Error);

   type Sys_Message is new CC30001_0.Msg_Type with record   -- Derived from

      Signal : Signal_Type := Warning;                      -- root type.

   end record;

   procedure Send (Item : in out Sys_Message); -- For this test, this version

                                               -- of Send should never be

   -- ... Other operations.                    -- called (it will have been

                                               -- overridden).

end CC30001_2;

     --==================================================================--

package body CC30001_2 is

   procedure Send (Item : in out Sys_Message) is

   begin

      -- ... Code to send message omitted for brevity.

      Item.Message_Sent := False;  -- Ensure this procedure gives a different

   end Send;                       -- result than CC30001_1.Send.

end CC30001_2;

     --==================================================================--

-- User first sets up support for mail messages by instantiating the

-- generic mail package for the root message type. An operation "Send" is

-- declared for the mail message type in the instance.

--

-- with CC30001_0;  -- Root message type.

-- with CC30001_1;  -- Generic "mail" package.

-- package Mail_Messages is new CC30001_1 (CC30001_0.Msg_Type);

     --==================================================================--

-- Next, the user sets up support for system messages by instantiating the

-- generic mail package with the system message type. An operation "Send"

-- is declared for the "system" mail message type in the instance. This

-- operation overrides the "Send" operation inherited from the system

-- message type actual (a situation the user may not have intended).

with CC30001_1;  -- Generic "mail" package.

with CC30001_2;  -- System message type and operations.

pragma Elaborate (CC30001_1);

package CC30001_3 is new CC30001_1 (CC30001_2.Sys_Message);

     --==================================================================--

with CC30001_2;  -- System message type and operations.

with CC30001_3;  -- Instance with mail type and operations.

with Report;

procedure CC30001 is

   package System_Messages renames CC30001_3;

   Sys_Msg1 : System_Messages.Mail_Type := (Text   => "System shutting down",

                                            Signal => CC30001_2.Warning,

                                            To     => "AllUsers",

                                            Message_Sent => False);

   Sys_Msg2 : System_Messages.Mail_Type'Class := Sys_Msg1;

   use System_Messages, CC30001_2;                 -- All versions of "Send"

                                                   -- directly visible.

begin

   Report.Test ("CC30001", "Check that if a non-overriding primitive "     &

                "subprogram is declared for a type derived from a formal " &

                "derived tagged type, the copy of that subprogram in an "  &

                "instance can override a subprogram inherited from the "   &

                "actual type");

   Send (Sys_Msg1);   -- Calls version declared in instance (version declared

                      -- in CC30001_2 has been overridden).

   if not Sys_Msg1.Message_Sent then

      Report.Failed ("Non-dispatching call: instance operation not called");

   end if;

   Send (Sys_Msg2);   -- Calls version declared in instance (version declared

                      -- in CC30001_2 has been overridden).

   if not Sys_Msg2.Message_Sent then

      Report.Failed ("Dispatching call: instance operation not called");

   end if;

   Report.Result;

end CC30001;