From: Bob Duff <bobduff@theworld.com>
Subject: Re: function Is_Open (File : File_Type) return Boolean; :Text_io
Date: Tue, 27 Oct 2015 09:30:54 -0400
Date: 2015-10-27T09:30:54-04:00 [thread overview]
Message-ID: <87pp0030c1.fsf@theworld.com> (raw)
In-Reply-To: 1pj15r7pul7f1.15qgdyrc8k133$.dlg@40tude.net
"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
> On Mon, 26 Oct 2015 18:48:51 -0400, Bob Duff wrote:
>
>> comicfanzine@gmail.com writes:
>>
>>> Can someone please show my a code in which this function is used , i'm
>>> lost , thanks .
>>
>> Most code is written so that it is statically known whether a file is
>> open, so Is_Open is close to useless. Not entirely useless -- you might
>> use it in an assertion, such as:
>>
>> subtype Open_File is File with Predicate => Is_Open(Open_File);
>
> In order to have the Constraint_Error exception instead of Status_Error?
No, in order to document the fact that a certain formal parameter must
be open, and in order to prove things statically. If a procedure takes
"F: Open_File", then we can easily prove that writes to F within that
procedure do not raise Status_Error.
> Looks entirely useless to me.
- Bob
next prev parent reply other threads:[~2015-10-27 13:30 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-26 10:00 function Is_Open (File : File_Type) return Boolean; :Text_io comicfanzine
2015-10-26 11:27 ` Simon Wright
2015-10-26 13:25 ` comicfanzine
2015-10-26 18:01 ` Simon Wright
2015-10-26 19:03 ` AdaMagica
2015-10-27 11:30 ` Simon Wright
2015-10-26 18:02 ` Jeffrey R. Carter
2015-10-26 13:28 ` comicfanzine
2015-10-26 15:07 ` Jacob Sparre Andersen
2015-10-26 16:37 ` AdaMagica
2015-10-26 20:46 ` J-P. Rosen
2015-10-27 8:42 ` comicfanzine
2015-10-27 11:34 ` Simon Wright
2015-10-28 13:32 ` comicfanzine
2015-10-27 8:51 ` comicfanzine
2015-10-27 17:15 ` Jeffrey R. Carter
2015-10-26 22:48 ` Bob Duff
2015-10-27 8:30 ` Dmitry A. Kazakov
2015-10-27 13:30 ` Bob Duff [this message]
2015-10-27 14:00 ` G.B.
2015-10-27 15:26 ` Dmitry A. Kazakov
2015-10-27 16:43 ` G.B.
2015-10-27 20:04 ` Dmitry A. Kazakov
2015-10-28 11:06 ` Georg Bauhaus
2015-10-28 17:58 ` Randy Brukardt
2015-10-28 18:20 ` Dmitry A. Kazakov
2015-10-28 20:36 ` Bob Duff
2015-10-28 21:02 ` Dmitry A. Kazakov
2015-10-29 11:25 ` AdaMagica
2015-10-29 13:37 ` Dmitry A. Kazakov
2015-10-29 17:57 ` AdaMagica
2015-10-29 18:12 ` AdaMagica
2015-10-29 18:26 ` Dmitry A. Kazakov
2015-10-30 8:27 ` Jacob Sparre Andersen
2015-10-30 9:11 ` J-P. Rosen
2015-10-29 11:47 ` G.B.
2015-10-29 13:01 ` J-P. Rosen
2015-10-29 14:00 ` Dmitry A. Kazakov
2015-10-30 1:06 ` Georg Bauhaus
2015-10-30 8:39 ` Dmitry A. Kazakov
2015-10-30 14:32 ` G.B.
2015-10-30 16:20 ` Dmitry A. Kazakov
2015-10-30 19:07 ` G.B.
2015-10-31 9:31 ` Dmitry A. Kazakov
2015-10-31 11:17 ` Georg Bauhaus
2015-10-30 14:40 ` G.B.
2015-10-30 16:26 ` Dmitry A. Kazakov
2015-10-28 20:07 ` Bob Duff
2015-10-28 20:59 ` Dmitry A. Kazakov
2015-10-27 14:02 ` G.B.
2015-10-27 15:10 ` Dmitry A. Kazakov
2015-10-27 16:41 ` G.B.
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