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-- CA11021.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 private 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 generic package which declares high level operations for a

--      complex number abstraction.  Declare a private generic child package

--      of this package which defines low level complex operations. In the

--      parent body, instantiate the private child.  Use the low level

--      operation to complete the high level operation.

--

--      In the main program, instantiate the parent generic package.

--      Check that the operations in both packages perform as expected.

--

--

-- CHANGE HISTORY:

--      06 Dec 94   SAIC    ACVC 2.0

--

--!

generic               -- Complex number abstraction.

   type Int_Type is range <>;

package CA11021_0 is

   -- Simulate a generic complex number support package. Complex numbers

   -- are treated as coordinates in the Cartesian plane.

   type Complex_Type is private;

   Zero : constant Complex_Type;                      -- Real number (0,0).

   function Real_Part (Complex_No : Complex_Type)

     return Int_Type;

   function Imag_Part (Complex_No : Complex_Type)

     return Int_Type;

   function Complex (Real, Imag : Int_Type)

     return Complex_Type;

   -- High level operation for complex number.

   function "*" (Factor : Int_Type;

                 C      : Complex_Type) return Complex_Type;

   -- ... and other complicated ones.

private

   type Complex_Type is record

      Real : Int_Type;

      Imag : Int_Type;

   end record;

   Zero : constant Complex_Type := (Real => 0, Imag => 0);

end CA11021_0;

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

-- Private generic child of Complex_Number.

private

generic

-- No parameter.

package CA11021_0.CA11021_1 is

   -- ... Other declarations.

   -- Low level operation on complex number.

   function "+" (Left, Right : Complex_Type)

     return Complex_Type;

   function "-" (Right : Complex_Type)

     return Complex_Type;

   -- ... Various other operations in real application.

end CA11021_0.CA11021_1;

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

package body CA11021_0.CA11021_1 is

   function "+" (Left, Right : Complex_Type)

     return Complex_Type is

   begin

      return ( (Left.Real + Right.Real, Left.Imag + Right.Imag) );

   end "+";

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

   function "-" (Right : Complex_Type) return Complex_Type is

   begin

      return (-Right.Real, -Right.Imag);

   end "-";

end CA11021_0.CA11021_1;

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

with CA11021_0.CA11021_1;    -- Private generic child package.

package body CA11021_0 is

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

   -- Parent's body depends on private generic child. --

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

   -- Instantiate the private child.

   package Complex_Ops is new CA11021_1;

   use Complex_Ops;                    -- All user-defined operators

                                       -- directly visible.

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

   function "*" (Factor : Int_Type;

                 C      : Complex_Type) return Complex_Type is

      Result : Complex_Type := Zero;

   begin

      for I in 1 .. abs (Factor) loop

         Result := Result + C;         -- Private generic child "+".

      end loop;

      if Factor < 0 then

         Result := - Result;           -- Private generic child "-".

      end if;

      return Result;

   end "*";

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

   function Real_Part (Complex_No : Complex_Type) return Int_Type is

   begin

      return (Complex_No.Real);

   end Real_Part;

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

   function Imag_Part (Complex_No : Complex_Type) return Int_Type is

   begin

      return (Complex_No.Imag);

   end Imag_Part;

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

   function Complex (Real, Imag : Int_Type) return Complex_Type is

   begin

      return (Real, Imag);

   end Complex;

end CA11021_0;

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

with CA11021_0;                        -- Complex number abstraction.

with Report;

procedure CA11021 is

   type My_Integer is range -100 .. 100;

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

-- Declare instance of the generic complex package for one particular

-- integer type.

   package My_Complex_Pkg is new

     CA11021_0 (Int_Type => My_Integer);

   use My_Complex_Pkg;                 -- All user-defined operators

                                       -- directly visible.

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

   Complex_One, Complex_Two : Complex_Type;

   My_Literal               : My_Integer := -3;

begin

   Report.Test ("CA11021", "Check that body of the generic parent package " &

                "can depend on its private generic child");

   Complex_One := Complex (11, 6);

   Complex_Two := 5 * Complex_One;

   if Real_Part (Complex_Two) /= 55

     and Imag_Part (Complex_Two) /= 30

        then

           Report.Failed ("Incorrect results from complex operation");

   end if;

   Complex_One := Complex (-4, 7);

   Complex_Two := My_Literal * Complex_One;

   if Real_Part (Complex_Two) /= 12

     and Imag_Part (Complex_Two) /= -21

        then

           Report.Failed ("Incorrect results from complex operation");

   end if;

   Report.Result;

end CA11021;