c840001.a

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-- C840001.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, for the type determined by the subtype mark of a use type
--      clause, the declaration of each primitive operator is use-visible
--      within the scope of the clause, even if explicit operators with the
--      same names as the type's operators are declared for the subtype. Check
--      that a call to such an operator executes the body of the type's
--      operation.
--
-- TEST DESCRIPTION:
--      A type may declare a primitive operator, and a subtype of that type
--      may overload the operator. If a use type clause names the subtype,
--      it is the primitive operator of the type (not the subtype) which
--      is made directly visible, and the primitive operator may be called
--      unambiguously. Such a call executes the body of the type's operation.
--
--      In a package, declare a type for which a predefined operator is
--      overridden.  In another package, declare a subtype of the type in the
--      previous package.  Declare another version of the predefined operator
--      for the subtype.
--
--      The main program declares objects of both the type and the explicit
--      subtype, and uses the "**" operator for both.  In all cases, the
--      operator declared for the 1st subtype should be the one executed,
--      since it is the primitive operators of the *type* that are made
--      visible; the operators which were declared for the explicit subtype
--      are not primitive operators of the type, since they were declared in
--      a separate package from the original type.
--
--
-- CHANGE HISTORY:
--      06 Dec 94   SAIC    ACVC 2.0
--      23 Sep 99   RLB     Added test case where operator made visible is
--                          not visible by selection (as in AI-00122).
--
--!

package C840001_0 is
-- Usage scenario: the predefined operators for a floating point type
-- are overridden in order to take advantage of improved algorithms.

   type Precision_Float is new Float range -100.0 .. 100.0;
   -- Implicit: function "**" (Left: Precision_Float; Right: Integer'Base)
   -- return Precision_Float;

   function "**" (Left: Precision_Float; Right: Integer'Base)
     return Precision_Float;
   -- Overrides predefined operator.

   function "+" (Right: Precision_Float)
     return Precision_Float;
   -- Overrides predefined operator.

   -- ... Other overridden operations.

   TC_Expected : constant Precision_Float := 68.0;

end C840001_0;


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

package body C840001_0 is

   function "**" (Left: Precision_Float; Right: Integer'Base)
     return Precision_Float is
   begin
      -- ... Utilize desired algorithm.
      return (TC_Expected);  -- Artificial for testing purposes.
   end "**";

   function "+" (Right: Precision_Float)
     return Precision_Float is
   -- Overrides predefined operator.
   begin
      return Right*2.0;
   end "+";

end C840001_0;


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

-- Take advantage of some even better algorithms designed for positive
-- floating point values.

with C840001_0;
package C840001_1 is

   subtype Precision_Pos_Float is C840001_0.Precision_Float
     range 0.0 .. 100.0;

-- This is not a new type, so it has no primitives of it own. However, it
-- can declare another version of the operator and call it as long as both it
-- and the corresponding operator of the 1st subtype are not directly visible
-- in the same place.

   function "**" (Left: Precision_Pos_Float; Right: Natural'Base)
     return Precision_Pos_Float;           -- Accepts only positive exponent.

end C840001_1;


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

package body C840001_1 is

   function "**" (Left: Precision_Pos_Float; Right: Natural'Base)
     return Precision_Pos_Float is
   begin
      -- ... Utilize some other algorithms.
      return 57.0;           -- Artificial for testing purposes.
   end "**";

end C840001_1;


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

with Report;
with C840001_1;
procedure C840001_2 is

   -- Note that C840001_0 and it's contents is not visible in any form here.

   TC_Operand   : C840001_1.Precision_Pos_Float := 41.0;

   TC_Operand2  : C840001_1.Precision_Pos_Float;

   use type C840001_1.Precision_Pos_Float;
      -- Makes the operators of its parent type directly visible, even though
      -- the parent type and operators are not otherwise visible at all.

begin

   TC_Operand2 := +TC_Operand; -- Overridden operator is visible and called.

   if TC_Operand2 /= 82.0 then -- Predefined equality.
      Report.Failed ("3rd test: type's overridden operation not called for " &
                     "operand of 1st subtype");
   end if;
   if TC_Operand + 3.0 >= TC_Operand2 - 13.0 then -- Various predefined operators.
      Report.Failed ("3rd test: wrong result from predefined operators");
   end if;

end C840001_2;

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


with C840001_0;
with C840001_1;
with C840001_2;

with Report;

procedure C840001 is

begin
   Report.Test ("C840001", "Check that, for the type determined by the "   &
                "subtype mark of a use type clause, the declaration of "   &
                "each primitive operator is use-visible within the scope " &
                "of the clause, even if explicit operators with the same " &
                "names as the type's operators are declared for the subtype");


   Use_Type_Precision_Pos_Float:
   declare
      TC_Operand          : C840001_0.Precision_Float
                          := C840001_0.Precision_Float(-2.0);
      TC_Positive_Operand : C840001_1.Precision_Pos_Float :=  6.0;

      TC_Actual_Type      : C840001_0.Precision_Float;
      TC_Actual_Subtype   : C840001_1.Precision_Pos_Float;

      use type C840001_1.Precision_Pos_Float;
      -- Both calls to "**" should return 68.0 (that is, Precision_Float's
      -- operation should be called).

   begin

      TC_Actual_Type := TC_Operand**2;

      if C840001_0."/="(TC_Actual_Type, C840001_0.TC_Expected) then
         Report.Failed ("1st block: type's operation not called for " &
                        "operand of 1st subtype");
      end if;

      TC_Actual_Subtype := TC_Positive_Operand**2;

      if not (C840001_0."="
             (TC_Actual_Subtype, C840001_0.TC_Expected)) then
         Report.Failed ("1st block: type's operation not called for " &
                        "operand of explicit subtype");
      end if;

   end Use_Type_Precision_Pos_Float;

   Use_Type_Precision_Float:
   declare
      TC_Operand          : C840001_0.Precision_Float
                          := C840001_0.Precision_Float(4.0);
      TC_Positive_Operand : C840001_1.Precision_Pos_Float :=  7.0;

      TC_Actual_Type      : C840001_0.Precision_Float;
      TC_Actual_Subtype   : C840001_1.Precision_Pos_Float;

      use type C840001_0.Precision_Float;
      -- Again, both calls to "**" should return 68.0.

  begin

      TC_Actual_Type := TC_Operand**2;

      if C840001_0."/="(TC_Actual_Type, C840001_0.TC_Expected) then
         Report.Failed ("2nd block: type's operation not called for " &
                        "operand of 1st subtype");
      end if;

      TC_Actual_Subtype := TC_Positive_Operand**2;

      if not C840001_0."=" (TC_Actual_Subtype, C840001_0.TC_Expected) then
         Report.Failed ("2nd block: type's operation not called for " &
                        "operand of explicit subtype");
      end if;

   end Use_Type_Precision_Float;

   C840001_2; -- 3rd test.

   Report.Result;

end C840001;