comp.lang.ada
 help / color / mirror / Atom feed
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: A hole in Ada type safety
Date: Sat, 7 May 2011 11:28:05 +0200
Date: 2011-05-07T11:28:05+02:00	[thread overview]
Message-ID: <hirpsfv33v9e$.1gzrgdlok5kja$.dlg@40tude.net> (raw)
In-Reply-To: 877ha2op0n.fsf@mid.deneb.enyo.de

On Sat, 07 May 2011 11:09:44 +0200, Florian Weimer wrote:

> Run-time complexity for reference counting is less than for full
> garbage collection.  Making it a language feature, rather than a
> library-provided functionality, makes it easier for implementations to
> optimize updating the counts.

Hmm, what about tasking? I gather that a built-in counter must be atomic.
Whether implemented lock-free or using a spin lock, that would be a
considerable overhead.

> As usual, there is a trade-off between
> flexibility and overhead: if the reference counters are kept separate,
> it is possible to implement weak pointers and safe references to
> sub-components.

Interesting. Do you have a certain schema in mind, how to this?

>> Type safety is not about detering malicious programmers, merely careless 
>> ones.
> 
> I think type safety is important for ending up with language semantics
> that can be explained.

I agree. It is the semantics which yields to safety, not the reverse.

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



  reply	other threads:[~2011-05-07  9:28 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-30  8:41 A hole in Ada type safety Florian Weimer
2011-04-30 11:56 ` Robert A Duff
2011-04-30 15:27   ` Gavino
2011-04-30 16:16   ` Florian Weimer
2011-04-30 23:39     ` Randy Brukardt
2011-05-01 10:26       ` Florian Weimer
2011-05-03  1:40         ` Randy Brukardt
2011-05-03 16:57           ` Robert A Duff
2011-05-07  9:09           ` Florian Weimer
2011-05-07  9:28             ` Dmitry A. Kazakov [this message]
2011-05-07  9:57               ` Florian Weimer
2011-05-08  8:08                 ` Dmitry A. Kazakov
2011-05-08  8:46                   ` Florian Weimer
2011-05-08  9:32                     ` Dmitry A. Kazakov
2011-05-08 10:30                       ` Florian Weimer
2011-05-08 20:24                         ` anon
2011-05-08 21:11                           ` Simon Wright
2011-05-10  6:27                             ` anon
2011-05-10 14:39                               ` Adam Beneschan
2011-05-11 20:39                                 ` anon
2011-05-12  0:51                                   ` Randy Brukardt
2011-05-13  0:47                                     ` anon
2011-05-13  0:58                                       ` Adam Beneschan
2011-05-13  5:31                                       ` AdaMagica
2011-05-12  5:51                                   ` AdaMagica
2011-05-12 12:09                                     ` Robert A Duff
2011-05-12 14:40                                     ` Adam Beneschan
2011-05-14  0:30                                       ` Randy Brukardt
2011-05-09  7:48                         ` Dmitry A. Kazakov
2011-05-09 20:41             ` Randy Brukardt
2011-05-14 23:47     ` anon
replies disabled

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox