c3a0010.a

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-- C3A0010.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 an access-to-subprogram type in a generic instance may be
--      used to declare access-to-subprogram objects which invoke subprograms
--      in the instance.
--
-- TEST DESCRIPTION:
--      Declare a numeric type in the visible part of a generic package.
--      Declare two different math procedures that can be referred to by 
--      the access to procedure type.  
--
--      In the main program, instantiate the generic.  Declare an access 
--      to procedure type.  Call each procedure indirectly by dereferencing 
--      the access value.
--
--
-- CHANGE HISTORY:
--      06 Dec 94   SAIC    ACVC 2.0
--      05 APR 96   SAIC    Header correction for 2.1
--
--!

generic
   type Real_Num is digits <>;

package C3A0010_0 is

   -- Type accesses to any math procedure
   type Math_Procedure_Ptr is access procedure   
       (First_Num, Second_Num : in  Real_Num;
        Result_Num            : out Real_Num);

   procedure Add      (First_Num, Second_Num : in  Real_Num;
                       Result_Num            : out Real_Num);

   procedure Subtract (First_Num, Second_Num : in  Real_Num;
                       Result_Num            : out Real_Num);

end C3A0010_0;


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


package body C3A0010_0 is

   procedure Add (First_Num, Second_Num : in  Real_Num;
                  Result_Num            : out Real_Num) is
   begin
      Result_Num := First_Num + Second_Num;
   end Add;


   procedure Subtract (First_Num, Second_Num : in  Real_Num;
                       Result_Num            : out Real_Num) is
   begin
      Result_Num := First_Num - Second_Num;
   end Subtract;

end C3A0010_0;

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

with Report;
with C3A0010_0; 

procedure C3A0010 is

   type Real is digits 2;

   subtype Math_Float is Real range -10.0 .. 10.0;

   package Math_Pk is new C3A0010_0 (Real_Num => Math_Float);

   Math_Access : Math_Pk.Math_Procedure_Ptr;

   Total_Num   : Math_Float := 0.0;
   First_Num   : Math_Float := 1.0;
   Second_Num  : Math_Float := 2.0;

   procedure Max( A_Num, B_Num: in Math_Float; Result : out Math_Float ) is
   begin
      if A_Num > B_Num then
        Result := A_Num;
      else
        Result := B_Num;
      end if;
   end Max;

   procedure Due_Process( Process: Math_Pk.Math_Procedure_Ptr ) is
   begin
     Process(First_Num, Second_Num, Total_Num);
   end Due_Process;

begin

   Report.Test ("C3A0010", "Check that an access-to-subprogram type in a "
                         & "generic instance may be used to declare "
                         & "access-to-subprogram objects which invoke "
                         & "subprograms in the instance");

-- Check for correct defaulting
   if Math_Pk."/="( Math_Access, null) then
     Report.Failed("subprogram access type object not initialized to null");
   end if;

   Math_Access := Math_Pk.Add'Access;

   -- Invoking Add procedure designated by access value
   Due_Process( Math_Access );

   If Total_Num /= 3.0 then
      Report.Failed ("Incorrect Add result");
   end if;

   Math_Access := Math_Pk.Subtract'Access;

   Due_Process( Math_Access );

   If Total_Num /= -1.0 then
      Report.Failed ("Incorrect Subtract result");
   end if;

   Math_Access := Max'Access;

   Due_Process( Math_Access );

   If Total_Num /= 2.0 then
      Report.Failed ("Incorrect Max result");
   end if;

   Report.Result;

end C3A0010;