From: Georg Bauhaus <rm.tsoh.plus-bug.bauhaus@maps.futureapps.de>
Subject: Re: unsigned type
Date: Fri, 03 Jul 2009 23:24:20 +0200
Date: 2009-07-03T23:24:21+02:00 [thread overview]
Message-ID: <4a4e7705$0$31863$9b4e6d93@newsspool3.arcor-online.net> (raw)
In-Reply-To: <pdu3m.99538$d36.35172@bgtnsc04-news.ops.worldnet.att.net>
anon wrote:
> Since the RM does not directly
> give one permission to use an illegal index value, then one should assume
> that all index must be valid before checking for a null array.
To "assume" formal properties like index validity seems inadequate:
this is about index ranges, not index values, and about what the RM
has to say about the formal notion of a "null range" (as has now been
said many times).
> Actually,
> Ada RM 0 ( 29 ) states that it is illegal and the program shall create
> an exception if the program "access an array component by using an
> incorrect index value".
There isn't any access to an array component through a null range.
For indexing an array component, one must have an index value.
There is no value in a null range. Therefore, there is no
access to an array component.
> Also, a number of ACATS test suggest this as well
> and the program below will illustrate this. With that stated from the RM
> the program shall
>
> if S'First in S'Range and then S'Last in S'Range then
> if S'First <= S'Last then
> -- access/create an array bound by ( S'First .. S'Last )
> else
> -- return a null created array access
> end if ;
> else
> raise Constraint_Error ;
> end if ;
>
> You have to look at the whole RM to find out if there are other sections
> that may clarify a statements or allow an exception. But there is no
> RM rules that allows an out of bounds index to be used.
Maybe the verse and illustrations given by J.-P. Rosen and
Adam Beneschan have slipped: There are RM rules regarding
null ranges. The construct "Greater .. Smaller" as used in, say,
initializing a null string refers to null ranges, so not to any
index value at all.
next prev parent reply other threads:[~2009-07-03 21:24 UTC|newest]
Thread overview: 113+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-28 15:36 unsigned type Rob Solomon
2009-06-28 15:45 ` Florian Weimer
2009-06-28 15:48 ` Albrecht Käfer
2009-06-28 17:56 ` anon
2009-06-28 19:17 ` Ludovic Brenta
2009-06-28 23:08 ` anon
2009-06-29 0:19 ` tmoran
2009-06-29 8:00 ` anon
2009-06-29 9:56 ` Jean-Pierre Rosen
2009-06-29 10:21 ` Ludovic Brenta
2009-06-29 11:23 ` sjw
2009-06-29 12:07 ` Jean-Pierre Rosen
2009-06-29 20:06 ` anon
2009-06-29 19:31 ` anon
2009-06-29 21:49 ` Georg Bauhaus
[not found] ` <zuKdneNYxfFNLNTXnZ2dnUVZ_t2dnZ2d@earthlink.com>
2009-06-30 11:29 ` anon
2009-06-30 12:19 ` Ludovic Brenta
2009-06-29 20:19 ` anon
2009-06-29 20:41 ` Ludovic Brenta
2009-06-29 22:15 ` Georg Bauhaus
2009-06-29 23:08 ` Adam Beneschan
2009-06-29 23:11 ` Adam Beneschan
2009-06-30 12:39 ` Martin
2009-06-29 10:25 ` Georg Bauhaus
2009-06-29 20:02 ` anon
2009-06-29 22:08 ` Georg Bauhaus
2009-06-30 23:01 ` Randy Brukardt
2009-06-30 13:46 ` Jean-Pierre Rosen
2009-06-30 15:22 ` Adam Beneschan
2009-06-30 15:59 ` Albrecht Käfer
2009-06-30 16:59 ` Adam Beneschan
2009-06-30 17:44 ` Albrecht Käfer
2009-06-30 18:13 ` Robert A Duff
2009-06-30 18:16 ` Albrecht Käfer
2009-06-30 23:48 ` anon
2009-07-01 1:39 ` Adam Beneschan
2009-07-02 19:04 ` anon
2009-07-02 19:49 ` anon
2009-07-02 21:37 ` Adam Beneschan
2009-07-03 1:42 ` anon
2009-07-03 2:10 ` Adam Beneschan
2009-07-03 7:07 ` Jean-Pierre Rosen
2009-07-03 20:53 ` anon
2009-07-03 21:24 ` Georg Bauhaus [this message]
2009-07-04 9:09 ` anon
2009-07-04 13:43 ` Georg Bauhaus
2009-07-06 9:04 ` AdaMagica
2009-07-03 21:46 ` Adam Beneschan
2009-07-04 12:39 ` Martin
2009-07-01 8:09 ` Jean-Pierre Rosen
2009-07-01 15:08 ` Albrecht Käfer
2009-07-11 14:40 ` Hibou57 (Yannick Duchêne)
2009-07-11 17:18 ` sjw
2009-07-11 18:15 ` Hibou57 (Yannick Duchêne)
2009-07-11 20:20 ` anon
2009-07-12 17:57 ` Samuel Tardieu
2009-07-12 18:24 ` AdaMagica
2009-07-13 22:03 ` anon
2009-07-14 7:58 ` Martin
2009-07-16 13:54 ` anon
2009-07-16 14:41 ` Martin
2009-07-16 15:12 ` Adam Beneschan
2009-07-11 14:43 ` Hibou57 (Yannick Duchêne)
2009-07-11 15:22 ` Albrecht Käfer
2009-06-29 8:42 ` Martin
2009-06-29 8:54 ` Dmitry A. Kazakov
2009-06-29 10:10 ` Martin
2009-06-29 12:34 ` Dmitry A. Kazakov
2009-06-29 19:26 ` anon
2009-06-29 23:02 ` Martin
2009-06-29 19:47 ` anon
2009-06-30 8:31 ` Ludovic Brenta
2009-06-28 19:54 ` tmoran
2009-06-28 22:34 ` Gary Scott
2009-06-28 23:15 ` John B. Matthews
2009-06-28 23:21 ` anon
2009-06-29 7:18 ` Dmitry A. Kazakov
2009-06-29 9:52 ` Georg Bauhaus
2009-06-29 12:43 ` Dmitry A. Kazakov
2009-06-29 13:36 ` Rob Solomon
2009-06-29 14:03 ` Robert A Duff
2009-06-29 14:13 ` Georg Bauhaus
2009-06-29 14:18 ` Ludovic Brenta
2009-06-29 15:40 ` Robert A Duff
2009-07-03 1:41 ` Rob Solomon
2009-07-03 7:12 ` Learning Ada (Was: unsigned type) Jacob Sparre Andersen
2009-07-03 8:38 ` Learning Ada Peter Hermann
2009-07-03 9:44 ` Georg Bauhaus
2009-07-03 22:20 ` Learning Ada (Was: unsigned type) anon
2009-07-04 14:53 ` Georg Bauhaus
2009-07-05 23:21 ` anon
2009-07-06 0:05 ` Ludovic Brenta
2009-07-06 0:19 ` Learning Ada Albrecht Käfer
2009-07-06 2:50 ` anon
2009-07-06 6:18 ` AdaMagica
2009-07-06 7:47 ` Jean-Pierre Rosen
2009-07-06 20:21 ` anon
2009-07-06 21:08 ` Georg Bauhaus
2009-07-06 22:43 ` Frank J. Lhota
2009-07-09 22:28 ` anon
2009-07-10 6:23 ` AdaMagica
2009-07-06 10:53 ` Learning Ada (Was: unsigned type) Georg Bauhaus
2009-07-06 19:34 ` anon
2009-07-06 20:29 ` Learning Ada Albrecht Käfer
2009-07-06 21:04 ` Learning Ada (Was: unsigned type) Georg Bauhaus
2009-07-07 19:25 ` sjw
2009-07-06 23:15 ` Randy Brukardt
2009-07-07 15:29 ` Adam Beneschan
2009-07-09 0:15 ` Randy Brukardt
2009-07-09 15:26 ` Adam Beneschan
2009-06-29 15:37 ` unsigned type Adam Beneschan
2009-07-06 20:20 ` Dave
2009-06-29 16:51 ` Martin Krischik
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