From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>
Subject: Re: Ada advocacy
Date: Thu, 29 Aug 2013 14:43:30 -0700
Date: 2013-08-29T14:43:30-07:00 [thread overview]
Message-ID: <kvofa4$dnc$1@adenine.netfront.net> (raw)
In-Reply-To: <wccli3kzfbx.fsf@shell01.TheWorld.com>
On 08/29/2013 08:28 AM, Robert A Duff wrote:
>
> Also, you can do
> multi-way waits with accept statements but not entry calls.
You can do
select
P1.E1; -- An entry call.
then abort
P2.E4; -- Another entry call.
end select;
to wait for 1 of 2 entry calls, and you can nest another ATC in there to do 3, and so on to whatever depth you like, so
I don't really see a reason for the language not to provide a multi-way select for entry calls.
> It just feels wrong to me for that to be a task. It's not
> really doing anything; it's just sitting around waiting
> to be told what to do -- like a protected object.
> The "do stuff" above is likely some simple action
> like putting data in a queue or taking it out.
> A protected object seems better for that -- perhaps it's
> "lower level", but it's the RIGHT level. And with a protected
> object, you don't need a 'terminate' alternative in this case
> -- protected objects just go away like any passive object
> (say, an integer).
Sure. You should use a passive construct for a passive concept. One of Ada 83's problems was the lack of such a thing.
Ada 95 added the protected object, which partially solves the problem; however, sometimes you need mutual exclusion for
something that has to perform a potentially blocking action, and you can't use a protected object for that, so you're
back to using a task for something passive.
Some Ada-83 compilers, such as the DEC compiler, had "passive tasks", which were essentially protected objects without
functions and without the restriction on what they could do. I think standardizing that concept would have been a better
solution than introducing protected objects with their limitations.
--
Jeff Carter
"Now go away or I shall taunt you a second time."
Monty Python and the Holy Grail
--- news://freenews.netfront.net/ - complaints: news@netfront.net ---
next prev parent reply other threads:[~2013-08-29 21:43 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-20 12:54 Ada advocacy tonyg
2012-03-20 13:54 ` Ludovic Brenta
2012-03-20 14:39 ` Marc C
2012-03-20 15:13 ` Ludovic Brenta
2012-03-20 16:34 ` Yannick Duchêne (Hibou57)
2012-03-20 16:35 ` Yannick Duchêne (Hibou57)
2012-03-20 20:06 ` Shark8
2012-03-20 15:42 ` Georg Bauhaus
2012-03-20 18:31 ` Jeffrey Carter
2012-03-20 21:42 ` anon
2012-03-20 23:05 ` Shark8
2012-03-21 0:32 ` Shark8
2012-03-21 1:58 ` Robert Love
2012-03-21 5:37 ` Per Sandberg
2012-03-25 11:10 ` Peter C. Chapin
2012-03-21 8:59 ` anon
2013-06-17 23:42 ` johannes falcone
2013-06-18 0:09 ` tmoran
2013-06-18 0:14 ` Leo Brewin
2013-06-18 0:59 ` Jeffrey Carter
2013-06-19 19:22 ` johannes falcone
2013-06-19 19:34 ` Jacob Sparre Andersen
2013-06-19 20:16 ` Shark8
2013-06-19 19:36 ` Ludovic Brenta
2013-08-30 7:36 ` johannes falcone
2013-06-18 1:28 ` Dennis Lee Bieber
2013-06-18 5:55 ` Peter Brooks
2013-06-18 17:15 ` Robert A Duff
2013-06-18 17:43 ` Bill Findlay
2013-06-18 19:22 ` Robert A Duff
2013-06-18 19:30 ` Bill Findlay
2013-08-27 13:34 ` Yannick Duchêne (Hibou57)
2013-08-27 14:08 ` Bill Findlay
2013-08-27 14:13 ` Bill Findlay
2013-08-27 21:25 ` J-P. Rosen
2013-08-28 7:45 ` Dmitry A. Kazakov
2013-08-27 22:42 ` Dennis Lee Bieber
2013-08-28 7:45 ` Maciej Sobczak
2013-08-28 8:58 ` Georg Bauhaus
2013-08-28 9:42 ` Dmitry A. Kazakov
2013-08-28 11:42 ` G.B.
2013-08-28 11:59 ` Dmitry A. Kazakov
2013-08-28 12:49 ` G.B.
2013-08-28 14:07 ` Dmitry A. Kazakov
2013-08-28 15:06 ` Eryndlia Mavourneen
2013-08-28 17:30 ` Dmitry A. Kazakov
2013-08-28 16:44 ` Yannick Duchêne (Hibou57)
2013-08-28 17:25 ` Dmitry A. Kazakov
2013-08-28 23:33 ` Dennis Lee Bieber
2013-08-29 7:15 ` Dmitry A. Kazakov
2013-08-29 14:47 ` Yannick Duchêne (Hibou57)
2013-08-29 19:15 ` Dmitry A. Kazakov
2013-08-29 15:28 ` Robert A Duff
2013-08-29 21:43 ` Jeffrey R. Carter [this message]
2013-08-30 23:52 ` Yannick Duchêne (Hibou57)
2013-08-31 0:05 ` Jeffrey R. Carter
2013-08-31 1:42 ` Shark8
2013-08-31 2:57 ` Shark8
2013-08-31 9:00 ` Dirk Craeynest
2013-08-31 1:48 ` Randy Brukardt
2013-09-02 7:13 ` Egil H H
2013-09-02 8:41 ` G.B.
2013-09-02 16:37 ` Egil H H
2013-08-29 15:46 ` Robert A Duff
2013-08-30 4:47 ` Jeffrey R. Carter
2013-08-30 16:54 ` Robert A Duff
2013-08-30 17:49 ` Jeffrey R. Carter
2013-08-30 22:41 ` Robert A Duff
2013-08-31 0:02 ` Jeffrey R. Carter
2013-08-31 14:47 ` Robert A Duff
2013-06-19 7:29 ` nevillednz
2013-08-27 13:39 ` Yannick Duchêne (Hibou57)
2013-09-02 18:45 ` Martin
2013-06-17 23:39 ` johannes falcone
2012-03-21 10:44 ` tonyg
2013-06-18 0:07 ` johannes falcone
2012-03-23 16:13 ` KK6GM
2013-06-13 15:33 ` david
2013-06-13 15:34 ` david
-- strict thread matches above, loose matches on Subject: below --
2003-08-26 20:33 Ada Advocacy Stephane Richard
2003-08-26 21:20 ` Luke A. Guest
2003-08-26 22:28 ` Stephane Richard
2003-08-26 23:04 ` Luke A. Guest
2003-08-27 16:15 ` Warren W. Gay VE3WWG
2003-08-27 23:06 ` Luke A. Guest
2003-08-28 10:39 ` Preben Randhol
2003-08-26 23:55 ` Chad R. Meiners
2003-08-27 0:44 ` Anisimkov
2003-08-27 8:26 ` Dmitry A. Kazakov
2003-08-27 20:12 ` Wes Groleau
2003-08-27 23:09 ` Luke A. Guest
2003-08-29 16:13 ` Jon S. Anthony
2003-08-29 18:15 ` Luke A. Guest
2003-08-28 8:34 ` Dmitry A. Kazakov
2003-08-27 8:29 ` Luke A. Guest
2003-08-28 5:29 ` Dmitriy Anisimkov
2003-09-01 21:26 ` Dave Thompson
2003-08-27 6:56 ` David Holm
2003-08-27 16:00 ` Rod Chapman
2003-08-29 6:38 ` Adrian Hoe
2003-08-29 9:34 ` Stephane Richard
2003-09-01 5:45 ` Adrian Hoe
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