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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Preventing type extensions
Date: Mon, 13 Sep 2010 22:30:51 +0200
Date: 2010-09-13T22:30:50+02:00	[thread overview]
Message-ID: <1qinn2jjeco14.1tvq2qzalwqbt$.dlg@40tude.net> (raw)
In-Reply-To: 878w35fqaa.fsf@mid.deneb.enyo.de

On Mon, 13 Sep 2010 20:32:13 +0200, Florian Weimer wrote:

> * Dmitry A. Kazakov:
> 
>>> Type extensions break encapsulation (at least if there non-abstract
>>> dispatching subprograms which contain some non-trivial code): the
>>> information which subprograms call each other under what circumstances
>>> leaks to the outside of the package. One very drastic way to
>>> implement that is to disallow type extensions for most non-abstract
>>> types you write, and consider the exceptions carefully.
>>
>> No, the actual problem here is re-dispatch. Just do not do that, it is
>> always bad.
> 
> How do you suggest to avoid redispatch?  Make non-dispatching calls to
> dispatching subprograms?

Yes.

> And how does this address the issue?

Because nothing can get broken by overriding, all targets are resolved.

> It makes it more likely that you cannot write a useful extension.

Why? I can override anything I need.

> Wouldn't it be better not to hide this aspect in the implementation?

This does not compute to me. Are you saying that if an operation gets
broken upon extension you won't allow to override it? (And if it is not
broken, why do you care?)

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



  reply	other threads:[~2010-09-13 20:30 UTC|newest]

Thread overview: 107+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-12 10:18 Preventing type extensions Florian Weimer
2010-09-12 11:59 ` Ludovic Brenta
2010-09-12 12:53   ` Florian Weimer
2010-09-12 21:23     ` Maciej Sobczak
2010-09-13  5:32       ` Florian Weimer
2010-09-13  7:13         ` Dmitry A. Kazakov
2010-09-13  9:19           ` Georg Bauhaus
2010-09-13  9:42             ` Dmitry A. Kazakov
2010-09-13 10:23               ` Niklas Holsti
2010-09-13 12:55                 ` Cyrille
2010-09-13 13:55                   ` Dmitry A. Kazakov
2010-09-13 21:13                   ` J-P. Rosen
2010-09-21 13:57                     ` Cyrille
2010-09-21 14:19                       ` Dmitry A. Kazakov
2010-09-21 14:44                         ` Cyrille
2010-09-21 16:25                           ` Dmitry A. Kazakov
2010-09-21 17:11                             ` Georg Bauhaus
2010-09-21 18:11                               ` Dmitry A. Kazakov
2010-09-23 20:00                                 ` Simon Wright
2010-09-23 20:49                                   ` Dmitry A. Kazakov
2010-09-24  9:10                                     ` Georg Bauhaus
2010-09-24 10:24                                       ` Dmitry A. Kazakov
2010-09-24 13:30                                 ` Niklas Holsti
2010-09-24 16:27                                   ` Dmitry A. Kazakov
2010-09-24 17:47                                     ` Niklas Holsti
2010-09-24 19:42                                       ` Dmitry A. Kazakov
2010-09-21 14:32                       ` J-P. Rosen
2010-09-21 15:02                         ` Cyrille
2010-09-21 15:26                           ` J-P. Rosen
2010-09-21 16:18                             ` Cyrille
2010-09-22  8:01                               ` J-P. Rosen
2010-09-22 17:28                                 ` Cyrille
2010-09-22 19:30                                   ` Ludovic Brenta
2010-09-22 19:51                                     ` Florian Weimer
2010-09-22 20:14                                       ` Dmitry A. Kazakov
2010-09-22 20:25                                         ` Florian Weimer
2010-09-22 20:38                                           ` Dmitry A. Kazakov
2010-09-22 21:25                                             ` Vinzent Hoefler
2010-09-22 21:20                                           ` Georg Bauhaus
2010-09-22 20:16                                       ` Ludovic Brenta
2010-09-22 20:34                                         ` Florian Weimer
2010-09-22 22:45                                           ` Britt Snodgrass
2010-09-23  8:02                                           ` Ludovic Brenta
2010-09-23 16:51                                     ` Pascal Obry
2010-09-23 18:37                                       ` Florian Weimer
2010-09-23 18:55                                         ` Pascal Obry
2010-09-23 20:28                                       ` Ludovic Brenta
2010-09-24  9:20                                         ` Ludovic Brenta
2010-09-24 14:49                                           ` Simon Wright
2010-09-24 15:09                                             ` Ludovic Brenta
2010-09-24 16:21                                           ` Robert A Duff
2010-09-25  7:10                                         ` Pascal Obry
2010-09-25 12:03                                           ` Brian Drummond
2010-09-24  8:16                                   ` J-P. Rosen
2010-09-24  8:39                                     ` Cyrille
2010-09-24  9:27                                       ` Cyrille
2010-09-29 16:47                                         ` J-P. Rosen
2010-09-30 10:08                                           ` Cyrille
2010-10-05 17:02                                             ` J-P. Rosen
2010-10-08  7:50                                               ` Cyrille
2010-10-08 13:58                                               ` Cyrille
2010-10-08 20:12                                                 ` Dmitry A. Kazakov
2010-10-11  7:57                                                   ` Cyrille
2010-10-11  8:24                                                     ` Dmitry A. Kazakov
2010-10-12  5:23                                                   ` Shark8
2010-10-13  9:06                                                 ` J-P. Rosen
2010-10-13 17:37                                                   ` Cyrille
2010-10-13 18:50                                                     ` Dmitry A. Kazakov
2010-09-21 14:50                       ` (see below)
2010-09-21 17:37                         ` Cyrille
2010-09-21 19:07                           ` (see below)
2010-09-13 13:05                 ` Dmitry A. Kazakov
2010-09-13 20:21                   ` Niklas Holsti
2010-09-13 21:00                     ` Dmitry A. Kazakov
2010-09-13 21:10                 ` J-P. Rosen
2010-09-14 12:16                   ` Niklas Holsti
2010-09-14 16:46                     ` Dmitry A. Kazakov
2010-09-14 18:08                       ` Niklas Holsti
2010-09-14 18:32                         ` Niklas Holsti
2010-09-15  8:18                         ` Dmitry A. Kazakov
2010-09-14 17:04                     ` J-P. Rosen
2010-09-13 15:12               ` Securing type extensions (was: Preventing type extensions) Georg Bauhaus
2010-09-13 15:29                 ` Securing type extensions Dmitry A. Kazakov
2010-09-13 17:23                 ` Simon Wright
2010-09-13 20:22                   ` Georg Bauhaus
2010-09-13 20:41                     ` Dmitry A. Kazakov
2010-09-14 10:02                       ` Georg Bauhaus
2010-09-14 12:22                         ` Dmitry A. Kazakov
2010-09-14 21:18                           ` Georg Bauhaus
2010-09-15  8:15                             ` Dmitry A. Kazakov
2010-09-15 20:47                               ` Georg Bauhaus
2010-09-16  7:47                                 ` Dmitry A. Kazakov
2010-09-16 11:52                                   ` Georg Bauhaus
2010-09-16 12:45                                     ` Dmitry A. Kazakov
2010-09-16 20:53                                       ` Georg Bauhaus
2010-09-16 21:37                                         ` Dmitry A. Kazakov
2010-09-17  8:45                                           ` Georg Bauhaus
2010-09-17  9:39                                             ` Dmitry A. Kazakov
2010-10-05  5:59                     ` Randy Brukardt
2010-09-13 18:32           ` Preventing " Florian Weimer
2010-09-13 20:30             ` Dmitry A. Kazakov [this message]
2010-09-22 19:41               ` Florian Weimer
2010-09-22 20:34                 ` Dmitry A. Kazakov
2010-09-22 21:10                   ` Georg Bauhaus
2010-09-17  0:16           ` Shark8
2010-09-17  7:04             ` AdaMagica
2010-09-17 21:05               ` Shark8
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