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-- CC50001.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, in an instance, each implicit declaration of a predefined

--      operator of a formal tagged private type declares a view of the

--      corresponding predefined operator of the actual type (even if the

--      operator has been overridden for the actual type). Check that the

--      body executed is determined by the type and tag of the operands.

--

-- TEST DESCRIPTION:

--      The formal tagged private type has an unknown discriminant part, and

--      is thus indefinite. This allows both definite and indefinite types

--      to be passed as actuals. For tagged types, definite implies

--      nondiscriminated, and indefinite implies discriminated (with known

--      or unknown discriminants).

--

--      Only nonlimited tagged types are tested, since equality operators

--      are not predefined for limited types.

--

--      A tagged type is passed as an actual to a generic formal tagged

--      private type. The tagged type overrides the predefined equality

--      operator. A subprogram within the generic calls the equality operator

--      of the formal type. In an instance, the equality operator denotes

--      a view of the predefined operator of the actual type, but the

--      call dispatches to the body of the overriding operator.

--

--

-- CHANGE HISTORY:

--      06 Dec 94   SAIC    ACVC 2.0

--      21 Nov 95   SAIC    ACVC 2.0.1 fixes: Corrected expected result on

--                          calls to "=" within the instance. Modified

--                          commentary.

--

--!

package CC50001_0 is

   type Count_Type is tagged record                     -- Nondiscriminated

      Count : Integer := 0;                             -- tagged type.

   end record;

   function "="(Left, Right : Count_Type)               -- User-defined

     return Boolean;                                    -- equality operator.

   subtype Str_Len is Natural range 0 .. 100;

   subtype Stu_ID  is String (1 .. 5);

   subtype Dept_ID is String (1 .. 4);

   subtype Emp_ID  is String (1 .. 9);

   type    Status   is (Student, Faculty, Staff);

   type Person_Type (Stat : Status;                     -- Discriminated

                     NameLen, AddrLen : Str_Len) is     -- tagged type.

     tagged record

      Name    : String (1 .. NameLen);

      Address : String (1 .. AddrLen);

      case Stat is

         when Student =>

            Student_ID  : Stu_ID;

         when Faculty =>

            Department  : Dept_ID;

         when Staff   =>

            Employee_ID : Emp_ID;

      end case;

   end record;

   function "="(Left, Right : Person_Type)              -- User-defined

     return Boolean;                                    -- equality operator.

   -- Testing entities: ------------------------------------------------

   TC_Count_Item     : constant Count_Type  := (Count => 111);

   TC_Person_Item    : constant Person_Type :=

     (Faculty, 18, 17, "Eccles, John Scott", "Popham House, Lee", "0931");

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

end CC50001_0;

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

package body CC50001_0 is

   function "="(Left, Right : Count_Type) return Boolean is

   begin

      return False;   -- Return FALSE even if Left = Right.

   end "=";

   function "="(Left, Right : Person_Type) return Boolean is

   begin

      return False;   -- Return FALSE even if Left = Right.

   end "=";

end CC50001_0;

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

with CC50001_0;  -- Tagged (actual) type declarations.

generic        -- Generic stack abstraction.

   type Item (<>) is tagged private;            -- Formal tagged private type.

package CC50001_1 is

   -- Simulate a generic stack abstraction. In a real application, the

   -- second operand of Push might be of type Stack, and type Stack

   -- would have at least one component (pointing to the top stack item).

   type Stack is private;

   procedure Push (I : in Item; TC_Check : out Boolean);

   -- ... Other stack operations.

private

   -- ... Stack and ancillary type declarations.

   type Stack is record                       -- Artificial.

      null;

   end record;

end CC50001_1;

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

package body CC50001_1 is

   -- For the sake of brevity, the implementation of Push is completely

   -- artificial; the goal is to model a call of the equality operator within

   -- the generic.

   --

   -- A real application might implement Push such that it does not add new

   -- items to the stack if they are identical to the top item; in that

   -- case, the equality operator would be called as part of an "if"

   -- condition.

   procedure Push (I : in Item; TC_Check : out Boolean) is

   begin

      TC_Check := not (I = I);              -- Call user-defined "="; should

                                            -- return FALSE. Negation of

                                            -- result makes TC_Check TRUE.

   end Push;

end CC50001_1;

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

with CC50001_0;  -- Tagged (actual) type declarations.

with CC50001_1;  -- Generic stack abstraction.

use  CC50001_0;  -- Overloaded "=" directly visible.

with Report;

procedure CC50001 is

   package Count_Stacks  is new CC50001_1 (CC50001_0.Count_Type);

   package Person_Stacks is new CC50001_1 (CC50001_0.Person_Type);

   User_Defined_Op_Called : Boolean;

begin

   Report.Test ("CC50001", "Check that, in an instance, each implicit "     &

                "declaration of a primitive subprogram of a formal tagged " &

                "private type declares a view of the corresponding "        &

                "predefined operator of the actual type (even if the "      &

                "operator has been overridden or hidden for the actual type)");

--

-- Test which "=" is called inside generic:

--

   User_Defined_Op_Called := False;

   Count_Stacks.Push (CC50001_0.TC_Count_Item,

                      User_Defined_Op_Called);

   if not User_Defined_Op_Called then

      Report.Failed ("User-defined ""="" not called inside generic for Count");

   end if;

   User_Defined_Op_Called := False;

   Person_Stacks.Push (CC50001_0.TC_Person_Item,

                       User_Defined_Op_Called);

   if not User_Defined_Op_Called then

      Report.Failed ("User-defined ""="" not called inside generic " &

                     "for Person");

   end if;

--

-- Test which "=" is called outside generic:

--

   User_Defined_Op_Called := False;

   User_Defined_Op_Called :=

     not (CC50001_0.TC_Count_Item = CC50001_0.TC_Count_Item);

   if not User_Defined_Op_Called then

      Report.Failed ("User-defined ""="" not called outside generic "&

                     "for Count");

   end if;

   User_Defined_Op_Called := False;

   User_Defined_Op_Called :=

     not (CC50001_0.TC_Person_Item = CC50001_0.TC_Person_Item);

   if not User_Defined_Op_Called then

      Report.Failed ("User-defined ""="" not called outside generic "&

                     "for Person");

   end if;

   Report.Result;

end CC50001;