How to access parent class/object?

How to access parent class/object?

[Adrian Hoe]

Hi,

I have the following codes (abbreviated):

package A is
   type A_Object is tagged private;
...
end A;

package B is
   type B_Object is new A_Object with private;
...
end B;

package C is
   type C_Object is new B_Object with private;
...
end C;

package D is
   type D_Object is new C_Object with private;
...
end D;

Now, I have the following declaration:

My_D_Object is D.D_Object;

How can I reference the parent objects?

procedure Process_C (C_Obj : access C_Object);
procedure Process_D (D_Obj : access D_Object);

How can I pass C_Object and D_Object into Process_C and Process_D
respectively given only My_D_Object is D.D_Object?

Thanks.
--
Adrian Hoe

Re: How to access parent class/object?

[Dmitry A. Kazakov]

On 24 Mar 2005 22:57:10 -0800, Adrian Hoe wrote:

> Hi,
> 
> I have the following codes (abbreviated):
> 
> package A is
>    type A_Object is tagged private;
> ...
> end A;
> 
> package B is
>    type B_Object is new A_Object with private;
> ...
> end B;
> 
> package C is
>    type C_Object is new B_Object with private;
> ...
> end C;
> 
> package D is
>    type D_Object is new C_Object with private;
> ...
> end D;
> 
> Now, I have the following declaration:
> 
> My_D_Object is D.D_Object;
> 
> How can I reference the parent objects?
> 
> procedure Process_C (C_Obj : access C_Object);
> procedure Process_D (D_Obj : access D_Object);
> 
> How can I pass C_Object and D_Object into Process_C and Process_D
> respectively given only My_D_Object is D.D_Object?

   My_D_Object : aliased D_Object := ...;

   Process_C (C_Object (My_D_Object)'Access);
   Process_D (My_D_Object'Access);

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: How to access parent class/object?

[Adrian Hoe]

Hi,

Sorry for polluting the bandwidth. I posted this thread without
thinking hard enough. Stupid me! :-)

For the benefits of newbies:

I use class wide type to over this problem.

package A is
   type A_Object is tagged private;
   type A_Object_Access is access all A_Object'Class;
...
end A;

package B is
   type B_Object is new A_Object with private;
   type B_Object_Access is access all B_Object'Class;
...
end B;

package C is
   type C_Object is new B_Object with private;
   type C_Object_Access is access all C_Object'Class;
...
end C;

package D is
   type D_Object is new C_Object with private;
   type D_Object_Access is access all D_Object'Class;
...
end D;

With the declaration:
   My_D_Object : D.D_Object_Access;

Now, call the procedure with:
   Process_C (C_Object_Access (My_D_Object));

This should solve the problem.

Cheers,
--
Adrian Hoe





Adrian Hoe wrote:
> Hi,
>
> I have the following codes (abbreviated):
>
> package A is
>    type A_Object is tagged private;
> ...
> end A;
>
> package B is
>    type B_Object is new A_Object with private;
> ...
> end B;
>
> package C is
>    type C_Object is new B_Object with private;
> ...
> end C;
>
> package D is
>    type D_Object is new C_Object with private;
> ...
> end D;
>
> Now, I have the following declaration:
>
> My_D_Object is D.D_Object;
>
> How can I reference the parent objects?
>
> procedure Process_C (C_Obj : access C_Object);
> procedure Process_D (D_Obj : access D_Object);
>
> How can I pass C_Object and D_Object into Process_C and Process_D
> respectively given only My_D_Object is D.D_Object?
> 
> Thanks.
> --
> Adrian Hoe

Re: How to access parent class/object?

[Adrian Hoe]

Hi,

Sorry for polluting the bandwidth. I posted this thread without
thinking hard enough. Stupid me! :-)

For the benefits of newbies:

I use class wide type to over this problem.

package A is
   type A_Object is tagged private;
   type A_Object_Access is access all A_Object'Class;
...
end A;

package B is
   type B_Object is new A_Object with private;
   type B_Object_Access is access all B_Object'Class;
...
end B;

package C is
   type C_Object is new B_Object with private;
   type C_Object_Access is access all C_Object'Class;
...
end C;

package D is
   type D_Object is new C_Object with private;
   type D_Object_Access is access all D_Object'Class;
...
end D;

With the declaration:
   My_D_Object : D.D_Object_Access;

Now, call the procedure with:
   Process_C (C_Object_Access (My_D_Object));

This should solve the problem.

Cheers,
--
Adrian Hoe





Adrian Hoe wrote:
> Hi,
>
> I have the following codes (abbreviated):
>
> package A is
>    type A_Object is tagged private;
> ...
> end A;
>
> package B is
>    type B_Object is new A_Object with private;
> ...
> end B;
>
> package C is
>    type C_Object is new B_Object with private;
> ...
> end C;
>
> package D is
>    type D_Object is new C_Object with private;
> ...
> end D;
>
> Now, I have the following declaration:
>
> My_D_Object is D.D_Object;
>
> How can I reference the parent objects?
>
> procedure Process_C (C_Obj : access C_Object);
> procedure Process_D (D_Obj : access D_Object);
>
> How can I pass C_Object and D_Object into Process_C and Process_D
> respectively given only My_D_Object is D.D_Object?
> 
> Thanks.
> --
> Adrian Hoe

Re: How to access parent class/object?

[Adrian Hoe]

Thanks Dmitry. I have just posted the solution.

I did not think hard enough. Sorry, anyway thanks again.

Cheers,
--
Adrian Hoe





Dmitry A. Kazakov wrote:
> On 24 Mar 2005 22:57:10 -0800, Adrian Hoe wrote:
>
> > Hi,
> >
> > I have the following codes (abbreviated):
> >
> > package A is
> >    type A_Object is tagged private;
> > ...
> > end A;
> >
> > package B is
> >    type B_Object is new A_Object with private;
> > ...
> > end B;
> >
> > package C is
> >    type C_Object is new B_Object with private;
> > ...
> > end C;
> >
> > package D is
> >    type D_Object is new C_Object with private;
> > ...
> > end D;
> >
> > Now, I have the following declaration:
> >
> > My_D_Object is D.D_Object;
> >
> > How can I reference the parent objects?
> >
> > procedure Process_C (C_Obj : access C_Object);
> > procedure Process_D (D_Obj : access D_Object);
> >
> > How can I pass C_Object and D_Object into Process_C and Process_D
> > respectively given only My_D_Object is D.D_Object?
>
>    My_D_Object : aliased D_Object := ...;
>
>    Process_C (C_Object (My_D_Object)'Access);
>    Process_D (My_D_Object'Access);
> 
> -- 
> Regards,
> Dmitry A. Kazakov
> http://www.dmitry-kazakov.de