From: danmcleran@hotmail.com
Subject: Re: Possible Ada deficiency?
Date: 9 Jan 2005 09:15:47 -0800
Date: 2005-01-09T09:15:47-08:00 [thread overview]
Message-ID: <1105290947.422412.195950@c13g2000cwb.googlegroups.com> (raw)
In-Reply-To: wccy8f4orfp.fsf@shell01.TheWorld.com
>If so, I think it's a minor one. As Randy pointed out, if you don't
>want child packages to do something nasty, then don't create any child
>packages.
Yes. But what if I want to hide implementation detail from all others
who would write child packages?
>In any case, as some folks have pointed out, you should think of
"adding
>a child of X" as very similar to "modifying the source code of X".
This is also spelled out in the Ada95 rationale. While I understand the
reasoning, I would also argue that it would be advantageous for a
package writer to have the power to restrict what child packages can
see and modify.
>If you don't want people to do that, you need some extra-lingual
>mechanism to restrict them.
That's exactly right. I would propose adding a new keyword,
'concealed', to allow a package writer to hide certain areas from all
child packages. A trivial example:
package Some_Package is
type Not_So_Secret_Type is private; --Child packages can see here
type Some_Type is concealed; --Child package cannot see here
private
--Child package can change Not_So_Secret_Value
type Not_So_Secret_Type is record
Not_So_Secret_Value : Integer := 0;
end record
concealed
--Child packages cannot change Secret_Value directly
type Some_Type is record
Secret_Value : Integer := 1;
end record
end Some_Package
With the addition of this construct, a package writer can choose what
areas should be directly visible to child packages, and what areas
should not. This would force a child package to use the parent
package's public interface when dealing with objects of type Some_Type,
rather than having full visibility into Some_Type's internal
representation.
next prev parent reply other threads:[~2005-01-09 17:15 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-31 18:15 Possible Ada deficiency? danmcleran
2004-12-31 19:12 ` Jeffrey Carter
2005-01-01 1:52 ` danmcleran
2005-01-01 2:37 ` Jeffrey Carter
2005-01-01 2:02 ` danmcleran
2005-01-01 14:11 ` Martin Krischik
2005-01-01 15:27 ` danmcleran
2005-01-02 17:49 ` Martin Krischik
2005-01-01 15:30 ` Stephen Leake
2005-01-01 15:57 ` danmcleran
2005-01-03 23:37 ` Randy Brukardt
2005-01-07 17:26 ` Nick Roberts
2005-01-07 18:26 ` danmcleran
2005-01-07 21:32 ` Randy Brukardt
2005-01-08 3:56 ` Nick Roberts
2005-01-08 18:15 ` Robert A Duff
2005-01-08 19:11 ` Jeffrey Carter
2005-01-08 20:03 ` Robert A Duff
2005-01-09 3:40 ` Jeffrey Carter
2005-01-09 17:30 ` Robert A Duff
2005-01-09 19:24 ` Jeffrey Carter
2005-01-09 21:56 ` Nick Roberts
2005-01-10 13:47 ` Dmitry A. Kazakov
2005-01-10 16:46 ` Duncan Sands
2005-01-10 17:58 ` Pascal Obry
2005-01-10 18:45 ` Dmitry A. Kazakov
2005-01-10 19:44 ` Pascal Obry
2005-01-11 10:05 ` Dmitry A. Kazakov
2005-01-11 7:24 ` Vinzent 'Gadget' Hoefler
2005-01-11 9:48 ` Dmitry A. Kazakov
2005-01-11 13:57 ` Vinzent 'Gadget' Hoefler
2005-01-11 21:52 ` Robert A Duff
2005-01-12 11:22 ` Dmitry A. Kazakov
2005-01-09 17:23 ` danmcleran
2005-01-09 17:46 ` Robert A Duff
2005-01-10 3:05 ` danmcleran
2005-01-09 18:41 ` Nick Roberts
2005-01-09 19:06 ` Martin Krischik
2005-01-09 20:10 ` Robert A Duff
2005-01-09 20:15 ` Robert A Duff
2005-01-11 14:13 ` Possible Ada deficiency? (goto) Peter Hermann
2005-01-11 14:54 ` Nick Roberts
2005-01-11 22:15 ` Robert A Duff
2005-01-12 10:17 ` Peter Hermann
2005-01-15 17:34 ` Robert A Duff
2005-01-15 17:58 ` Dmitry A. Kazakov
2005-01-15 19:34 ` Robert A Duff
2005-01-10 20:15 ` Possible Ada deficiency? Randy Brukardt
2005-01-10 21:51 ` Robert A Duff
2005-01-11 20:23 ` Randy Brukardt
2005-01-11 21:24 ` Robert A Duff
2005-01-12 19:57 ` Randy Brukardt
2005-01-02 15:51 ` Adrian Hoe
2005-01-04 16:06 ` Peter Hermann
2005-01-01 23:36 ` tmoran
2005-01-02 3:38 ` danmcleran
2004-12-31 19:16 ` Martin Dowie
2005-01-01 2:32 ` Jeffrey Carter
2004-12-31 23:23 ` Nick Roberts
2005-01-01 1:56 ` danmcleran
2005-01-01 11:43 ` Dmitry A. Kazakov
2005-01-01 15:46 ` danmcleran
2005-01-01 17:58 ` Larry Kilgallen
2005-01-01 19:43 ` danmcleran
2005-01-02 0:36 ` Ed Falis
2005-01-02 3:36 ` danmcleran
2005-01-02 15:53 ` Ed Falis
2005-01-07 18:31 ` danmcleran
2005-01-07 18:44 ` Pascal Obry
2005-01-07 19:29 ` danmcleran
2005-01-07 21:28 ` Pascal Obry
2005-01-01 23:28 ` danmcleran
2005-01-02 10:26 ` Dmitry A. Kazakov
2005-01-02 15:51 ` danmcleran
2005-01-03 23:48 ` Randy Brukardt
2005-01-01 14:06 ` Martin Krischik
2005-01-01 15:53 ` danmcleran
2005-01-07 21:33 ` Robert A Duff
2005-01-09 17:15 ` danmcleran [this message]
2005-01-09 17:38 ` Robert A Duff
2005-01-10 3:16 ` danmcleran
2005-01-09 18:41 ` Martin Dowie
2005-01-10 3:18 ` danmcleran
2005-01-10 20:32 ` Randy Brukardt
2005-01-10 21:42 ` danmcleran
2005-01-10 21:36 ` Robert A Duff
2005-01-10 21:44 ` danmcleran
2005-01-09 19:01 ` Jeffrey Carter
2005-01-10 3:20 ` danmcleran
2005-01-10 22:16 ` Robert A Duff
2005-01-10 22:29 ` danmcleran
2005-01-11 20:12 ` Georg Bauhaus
2005-01-11 20:30 ` danmcleran
2005-01-11 21:44 ` Robert A Duff
2005-01-11 0:06 ` Jeffrey Carter
2005-01-11 0:46 ` Robert A Duff
2005-01-11 20:37 ` danmcleran
2005-01-11 21:08 ` Robert A Duff
2005-01-17 4:40 ` Tucker
2005-01-18 13:46 ` danmcleran
2005-01-18 21:29 ` Nick Roberts
2005-01-24 17:23 ` danmcleran
-- strict thread matches above, loose matches on Subject: below --
2004-12-31 19:06 danmcleran
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