From: "John B. Matthews" <nospam@nospam.invalid>
Subject: Re: Operation can be dispatching in only one type
Date: Wed, 02 Dec 2009 07:35:39 -0500
Date: 2009-12-02T07:35:39-05:00 [thread overview]
Message-ID: <nospam-9C9974.07353802122009@news.aioe.org> (raw)
In-Reply-To: 1jcbtmi5rztyp$.norvlhez9i9$.dlg@40tude.net
In article <1jcbtmi5rztyp$.norvlhez9i9$.dlg@40tude.net>,
"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote:
Georg Bauhaus wrote:
> > From the Java point of view, there are no false positives
> > or negatives.
>
> Of course there are, because it is a halting problem. So you need
> some optimistic or pessimistic estimation of:
>
> if False then
> Print (X.Tire); -- Is this illegal? If yes, that is a false positive
> end if;
It would be indeterminate but for doing "a specific conservative flow
analysis." In the specific cases of boolean constant expressions and if
statements,
if (true) { spare = new Tire(); } // spare assigned
if (1 == 1) { spare = new Tire(); } // spare assigned
if (false) { spare = new Tire(); } // spare unassigned
if (1 == 2) { spare = new Tire(); } // spare unassigned
if (always()) { spare = new Tire(); } // spare unassigned
static boolean always() { return true; }
In particular, spare remains unassigned even though the function
always() is always true.
In Ada, a certain compiler may warn 'variable "N" is assigned but never
read' for the following:
N : Integer;
if False then N := 1; end if;
I'm not especially advocating applying the Java rules to Ada, but I like
the warning.
<http://java.sun.com/docs/books/jls/third_edition/html/defAssign.html>
--
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>
next prev parent reply other threads:[~2009-12-02 12:35 UTC|newest]
Thread overview: 132+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-13 20:12 Operation can be dispatching in only one type xorque
2009-11-13 20:34 ` Dmitry A. Kazakov
2009-11-13 20:43 ` xorque
2009-11-13 21:14 ` Dmitry A. Kazakov
2009-11-13 20:44 ` xorque
2009-11-16 17:43 ` Adam Beneschan
2009-11-16 20:28 ` Dmitry A. Kazakov
2009-11-16 20:32 ` Dmitry A. Kazakov
2009-11-16 21:35 ` Adam Beneschan
2009-11-16 22:28 ` Dmitry A. Kazakov
2009-11-17 22:10 ` Adam Beneschan
2009-11-18 9:46 ` Dmitry A. Kazakov
2009-11-18 16:39 ` Adam Beneschan
2009-11-18 19:21 ` Dmitry A. Kazakov
2009-11-19 0:27 ` Randy Brukardt
2009-11-19 2:11 ` Robert A Duff
2009-11-19 15:57 ` Adam Beneschan
2009-11-19 19:39 ` Robert A Duff
2009-11-19 23:43 ` Randy Brukardt
2009-11-19 8:50 ` Dmitry A. Kazakov
2009-11-19 23:54 ` Randy Brukardt
2009-11-20 8:34 ` Dmitry A. Kazakov
2009-11-20 10:58 ` Jean-Pierre Rosen
2009-11-21 6:02 ` Randy Brukardt
2009-11-21 13:07 ` Dmitry A. Kazakov
2009-11-22 5:45 ` xorque
2009-11-22 11:25 ` Georg Bauhaus
2009-11-22 11:30 ` xorque
2009-11-22 16:25 ` Dmitry A. Kazakov
2009-11-22 16:27 ` xorque
2009-11-22 16:42 ` Dmitry A. Kazakov
2009-11-22 16:52 ` xorque
2009-11-22 17:41 ` Dmitry A. Kazakov
2009-11-22 18:03 ` xorque
2009-11-22 18:08 ` xorque
2009-11-22 18:28 ` Dmitry A. Kazakov
2009-11-22 18:41 ` xorque
2009-11-22 21:47 ` Robert A Duff
2009-11-23 3:42 ` stefan-lucks
2009-11-30 20:36 ` Robert A Duff
2009-11-30 23:54 ` (see below)
2009-12-01 12:13 ` Georg Bauhaus
2009-12-01 12:23 ` Georg Bauhaus
2009-12-01 12:44 ` Georg Bauhaus
2009-12-01 13:48 ` Dmitry A. Kazakov
2009-12-01 15:02 ` Georg Bauhaus
2009-12-01 16:18 ` Dmitry A. Kazakov
2009-12-01 17:52 ` Georg Bauhaus
2009-12-01 18:47 ` Dmitry A. Kazakov
2009-12-01 21:53 ` John B. Matthews
2009-12-02 0:32 ` Georg Bauhaus
2009-12-02 11:18 ` John B. Matthews
2009-12-02 14:29 ` Jean-Pierre Rosen
2009-12-02 15:35 ` Georg Bauhaus
2009-12-02 1:13 ` Georg Bauhaus
2009-12-02 9:07 ` Dmitry A. Kazakov
2009-12-02 12:35 ` John B. Matthews [this message]
2009-12-02 13:35 ` Dmitry A. Kazakov
2009-12-03 5:23 ` Randy Brukardt
2009-12-03 20:21 ` John B. Matthews
2009-12-03 5:29 ` Randy Brukardt
2009-12-03 11:24 ` Georg Bauhaus
2009-12-03 23:08 ` Randy Brukardt
2009-12-04 8:52 ` Dmitry A. Kazakov
2009-12-05 2:45 ` Randy Brukardt
2009-12-05 10:32 ` Dmitry A. Kazakov
2009-12-08 0:19 ` Randy Brukardt
2009-12-08 4:30 ` stefan-lucks
2009-12-08 9:12 ` Dmitry A. Kazakov
2009-12-10 4:09 ` Randy Brukardt
2009-12-11 0:10 ` Robert A Duff
2009-12-08 9:22 ` Dmitry A. Kazakov
2009-12-08 10:06 ` Georg Bauhaus
2009-12-08 10:23 ` Dmitry A. Kazakov
2009-12-08 10:33 ` Georg Bauhaus
2009-12-08 10:49 ` Dmitry A. Kazakov
2009-12-01 23:51 ` Randy Brukardt
2009-11-23 8:52 ` Dmitry A. Kazakov
2009-11-30 20:43 ` Robert A Duff
2009-12-01 9:00 ` Dmitry A. Kazakov
2009-12-01 5:45 ` stefan-lucks
2009-12-01 11:12 ` Dmitry A. Kazakov
2009-12-01 8:01 ` stefan-lucks
2009-12-01 13:37 ` Dmitry A. Kazakov
2009-12-15 23:54 ` Robert A Duff
2009-11-23 7:48 ` Georg Bauhaus
2009-11-23 7:58 ` Georg Bauhaus
2009-11-19 16:04 ` Adam Beneschan
2009-11-19 2:23 ` tmoran
2009-11-19 8:32 ` Dmitry A. Kazakov
-- strict thread matches above, loose matches on Subject: below --
2015-11-23 10:23 operation " Serge Robyns
2015-11-23 11:29 ` Dmitry A. Kazakov
2015-11-23 13:05 ` Serge Robyns
2015-11-23 13:48 ` Dmitry A. Kazakov
2015-11-23 14:16 ` Serge Robyns
2015-11-23 14:59 ` G.B.
2015-11-23 15:52 ` Dmitry A. Kazakov
2015-11-23 17:40 ` Jeffrey R. Carter
2015-11-24 9:08 ` Serge Robyns
2015-11-24 16:44 ` AdaMagica
2015-11-24 17:09 ` Jeffrey R. Carter
2015-11-24 18:37 ` Serge Robyns
2015-11-24 20:18 ` Jeffrey R. Carter
2015-11-24 20:40 ` Serge Robyns
2015-11-24 20:25 ` Niklas Holsti
2015-11-24 21:48 ` Jeffrey R. Carter
2015-11-25 8:24 ` Dmitry A. Kazakov
2015-11-25 11:22 ` Serge Robyns
2015-11-25 17:38 ` Dmitry A. Kazakov
2015-11-26 11:30 ` Serge Robyns
2015-11-26 13:14 ` Dmitry A. Kazakov
2015-11-26 14:27 ` Serge Robyns
2015-11-26 15:16 ` J-P. Rosen
2015-11-26 18:27 ` Serge Robyns
2015-11-26 21:20 ` J-P. Rosen
2015-11-27 8:37 ` Dmitry A. Kazakov
2015-11-27 12:58 ` J-P. Rosen
2015-11-27 13:39 ` Dmitry A. Kazakov
2015-11-30 22:22 ` Randy Brukardt
2015-12-01 8:46 ` Dmitry A. Kazakov
2015-12-01 11:19 ` G.B.
2015-12-01 13:56 ` Dmitry A. Kazakov
2015-12-01 16:05 ` G.B.
2015-12-01 17:58 ` Dmitry A. Kazakov
2015-12-02 13:06 ` G.B.
2015-12-02 13:31 ` Dmitry A. Kazakov
2015-12-02 19:33 ` Randy Brukardt
2015-12-02 19:27 ` Randy Brukardt
2015-11-29 17:59 ` Jacob Sparre Andersen
2015-11-30 22:29 ` Randy Brukardt
2015-11-25 12:27 ` G.B.
2015-11-25 17:25 ` Dmitry A. Kazakov
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