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From: "G.B." <bauhaus@futureapps.invalid>
Subject: Re: A bad counterintuitive behaviour of Ada about OO
Date: Mon, 11 Aug 2014 13:35:22 +0200
Date: 2014-08-11T13:35:22+02:00	[thread overview]
Message-ID: <lsa9pr$opm$1@dont-email.me> (raw)
In-Reply-To: <6c67704a-d399-433d-bd8e-4566e79defaf@googlegroups.com>

On 11.08.14 09:58, Maciej Sobczak wrote:
> procedure Use_Specific_Factory (F : in Specific_Factory) is
>
>     SP : Specific_Product := F.Make_Product;
>
> begin
>     -- ...
> end;
>
> And there is no way to make*both*  work in Ada. You can get one or the other but not both.


Is this a correct paraphrase?

"To make this practically work in Ada, one has to write

procedure Use_Specific_Factory (F : in Specific_Factory) is

     SP : Specific_Product := Specific_Product (F.Make_Product);

begin
     -- ...
end;

"and watch for run-time dispatching."

Where

   function Make_Product (Shop : access Factory)
     return Product'Class is abstract;

can be overridden as a prim op of Factory.
The variance becomes a property of its invocation context.




  parent reply	other threads:[~2014-08-11 11:35 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-05 20:09 A bad counterintuitive behaviour of Ada about OO Victor Porton
2014-08-05 20:58 ` Simon Wright
2014-08-05 21:06   ` Victor Porton
2014-08-05 21:51     ` Niklas Holsti
2014-08-05 22:13       ` Victor Porton
2014-08-05 22:35   ` Victor Porton
2014-08-05 23:25     ` Adam Beneschan
2014-08-05 20:59 ` Dmitry A. Kazakov
2014-08-05 21:07   ` Victor Porton
2014-08-05 22:39     ` Shark8
2014-08-05 21:11   ` Victor Porton
2014-08-06  7:26     ` Dmitry A. Kazakov
2014-08-07  7:41       ` Maciej Sobczak
2014-08-07  8:50         ` Dmitry A. Kazakov
2014-08-08  7:54           ` Maciej Sobczak
2014-08-08  8:14             ` Dmitry A. Kazakov
2014-08-08 13:06               ` Maciej Sobczak
2014-08-08 13:22                 ` Dmitry A. Kazakov
2014-08-08 22:32                   ` Randy Brukardt
2014-08-09 16:11                   ` Maciej Sobczak
2014-08-09 16:48                     ` Dmitry A. Kazakov
2014-08-10 20:55                       ` Maciej Sobczak
2014-08-11  7:41                         ` Dmitry A. Kazakov
2014-08-11  7:58                           ` Maciej Sobczak
2014-08-11  8:23                             ` Dmitry A. Kazakov
2014-08-12  7:50                               ` Maciej Sobczak
2014-08-11 11:35                             ` G.B. [this message]
2014-08-08 22:26                 ` Randy Brukardt
2014-08-08  8:34             ` Shark8
2014-08-08 12:59               ` Maciej Sobczak
2014-08-08 22:37                 ` Randy Brukardt
2014-08-08 22:53                   ` Jeffrey Carter
2014-08-07  8:58         ` J-P. Rosen
2014-08-07  9:40           ` Dmitry A. Kazakov
2014-08-07 11:17             ` J-P. Rosen
2014-08-07 12:28               ` Dmitry A. Kazakov
2014-08-07 13:34                 ` J-P. Rosen
2014-08-07 16:10                   ` Dmitry A. Kazakov
2014-08-07 18:14                     ` Robert A Duff
2014-08-07 19:41                       ` Dmitry A. Kazakov
2014-08-07 20:53                         ` Robert A Duff
2014-08-08  7:43                           ` Dmitry A. Kazakov
2014-08-08  8:18                             ` Shark8
2014-08-08  7:45                     ` J-P. Rosen
2014-08-08  8:04                       ` Dmitry A. Kazakov
2014-08-08  8:55                         ` J-P. Rosen
2014-08-08  9:13                           ` Dmitry A. Kazakov
2014-08-08 10:01                             ` J-P. Rosen
2014-08-08 10:53                               ` Dmitry A. Kazakov
2014-08-08 10:56                                 ` Victor Porton
2014-08-08 12:00                                 ` J-P. Rosen
2014-08-08 13:11                                   ` Dmitry A. Kazakov
2014-08-08 13:53                                     ` J-P. Rosen
2014-08-08 20:23                                       ` Dmitry A. Kazakov
2014-08-07 20:29                   ` Shark8
2014-08-08  7:49                     ` J-P. Rosen
2014-08-08  8:12                       ` Shark8
2014-08-08  8:26                         ` Dmitry A. Kazakov
2014-08-08 11:10                           ` Shark8
2014-08-08 11:20                             ` Dmitry A. Kazakov
2014-08-08 19:34                               ` Shark8
2014-08-08 20:23                                 ` Dmitry A. Kazakov
2014-08-07 15:03           ` Jeffrey Carter
2014-08-08  7:48           ` Maciej Sobczak
2014-08-08  8:51             ` J-P. Rosen
2014-08-08 13:25               ` Maciej Sobczak
2014-08-08 13:34                 ` J-P. Rosen
2014-08-08 13:52                   ` Dmitry A. Kazakov
2014-08-08 14:21                     ` J-P. Rosen
2014-08-08 20:23                       ` Dmitry A. Kazakov
2014-08-08 22:08                     ` Randy Brukardt
2014-08-08 22:18                 ` Randy Brukardt
2014-08-06  4:50 ` Per Sandberg
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