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From: Stefan.Lucks@uni-weimar.de
Subject: Re: A function that cannot be called?
Date: Thu, 18 Oct 2018 17:33:19 +0200
Date: 2018-10-18T17:33:19+02:00	[thread overview]
Message-ID: <alpine.DEB.2.21.1810181727240.13871@hexenstieg> (raw)
In-Reply-To: <pq9tf7$9bf$1@dont-email.me>

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On Thu, 18 Oct 2018, G.B. wrote:

> There is a type declaration, I rememberd, in Ada, that
> does not allow any object of the type to be declared.

What, exactly, is the point of your question?

If you really want to define a type, which does not allow any object of 
that type to be declared, here is one such type:

   type Void is abstract tagged null record;

Note that objects of type Void'class can exist, but never, ever, any 
objects of type Void. Thus, for good reason the Ada compiler refuses to 
compile

   function Impossible(X: T) return Void;





--------  I  love  the  taste  of  Cryptanalysis  in  the morning!  --------
www.uni-weimar.de/de/medien/professuren/mediensicherheit/people/stefan-lucks
----Stefan.Lucks (at) uni-weimar.de, Bauhaus-Universität Weimar, Germany----

  reply	other threads:[~2018-10-18 15:33 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-18 12:14 A function that cannot be called? G.B.
2018-10-18 15:33 ` Stefan.Lucks [this message]
2018-10-18 20:21   ` G.B.
2018-10-18 20:57     ` Niklas Holsti
2018-10-19  7:15     ` Dmitry A. Kazakov
2018-10-19 13:55       ` G.B.
2018-10-19 15:31         ` Dmitry A. Kazakov
2018-10-18 17:03 ` AdaMagica
2018-10-18 19:36   ` G.B.
2018-10-18 21:30     ` Randy Brukardt
2018-10-19 14:00       ` G.B.
2018-10-19 15:39         ` Dmitry A. Kazakov
2018-10-20  1:34         ` Randy Brukardt
2018-10-20  9:14           ` G.B.
2018-10-20 11:13             ` Simon Wright
2018-10-20 14:11               ` Dmitry A. Kazakov
2018-10-21  9:25                 ` G.B.
2018-10-21  9:07               ` G.B.
2018-10-21  9:51                 ` Dmitry A. Kazakov
2018-10-21 10:57                 ` Niklas Holsti
2018-10-21 18:00                 ` Simon Wright
2018-10-19  8:48 ` AdaMagica
2018-10-19 11:15   ` G.B.
2018-10-19 17:06     ` AdaMagica
2018-10-19 19:57       ` G.B.
2018-10-19 22:06         ` Jere
2018-10-21 10:14           ` G.B.
2018-10-21 11:30             ` Egil H H
2018-10-23 11:45               ` G.B.
2018-10-23 14:35                 ` Jere
2018-10-23 14:57                   ` Dmitry A. Kazakov
2018-10-23 17:49                     ` G.B.
2018-10-23 19:25                       ` Dmitry A. Kazakov
2018-10-24  7:35                         ` G.B.
2018-10-24  8:14                           ` Dmitry A. Kazakov
2018-10-19 18:19 ` marciant
2018-10-19 18:22   ` marciant
2018-10-20  1:36     ` Randy Brukardt
2018-10-20  2:54       ` marciant
2018-10-19 20:25   ` Shark8
2018-10-19 23:28     ` marciant
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