stacks.ads

Ada 2005 Training Notes.

with LimitedPrivateType;

package Stacks is

   type Object_Stack is tagged private;
   --
   -- Base type
   --
   type Object is tagged
      record
         X: Float;
         Y: Float;
      end record;

   --
   -- Object_Ptr is access to all types tagged as Object and
   -- its derived types.
   --
   type Object_Class_Ptr is access all Object'Class;
   --
   -- Derived type of Object
   --
   type Point is new Object with null record;
   type Circle is new Object with
      record
   	Radius: Float;
      end record;

   procedure Push(OS: in out Object_Stack'Class; OCA: Object_Class_Ptr);
   function "=" (First_OS, Second_OS: Object_Stack'Class) return Boolean;

   Abyss_Object: Object := Object'(X=>0.0, Y=>0.0);

   --
   --
   -- Can Assign parameter P since its declared private
   --
   procedure LimitedPrivateTypeCannotBeAssigned(P: LimitedPrivateType.PrivateCell);

   --
   -- Can not assign parameter P since its type is limited private
   --
   procedure LimitedPrivateTypeCanBeInitialized(P: LimitedPrivateType.LimitedPrivateCell);


private
   --
   -- Inherited by all Object'Class types
   --
   function Distance(OC: Object'Class) return Float;

   Max: constant := 100;
   type Object_Vector is array (Integer range <>) of Object_Class_Ptr;
   type Object_Stack is tagged
      record
         S: Object_Vector(1..Max);
         Top: Integer range 0..Max := 0;
      end record;
end;