From: Dmitry A. Kazakov <mailbox@dmitry-kazakov.de>
Subject: Re: status of Ada STL?
Date: Wed, 19 Jun 2002 14:37:35 +0200
Date: 2002-06-19T14:37:35+02:00 [thread overview]
Message-ID: <ibt0hu4fdr9ql5duvgogp9iv6vf57kqgr7@4ax.com> (raw)
In-Reply-To: bebbba07.0206182132.25e9ca2a@posting.google.com
On 18 Jun 2002 22:32:12 -0700, 18k11tm001@sneakemail.com (Russ) wrote:
>Dmitry A.Kazakov <mailbox@dmitry-kazakov.de> wrote in message news:<aemvpd$8dojl$1@ID-77047.news.dfncis.de>...
>> Russ wrote:
>>
>> > Immediately after the statement "x=3" executes, it becomes true in the
>> > mathematical sense, which is why it makes sense.
>>
>> Nope. Consider C++ having user-defined type conversions. It is very easy to
>> write a program in C++ that
>>
>> SomeClass x;
>>
>> x=3;
>> if (x==3) // false
>
>I should have been more specific. For any instance x of a built-in
>numerical type, the statement "x=3" becomes true in a mathematical
>sense immediately after it executes. (If I am wrong, please provide a
>counter-example.)
1. From ADT point of view there is no difference between numerical,
built-in or whatsoever types and other types. There are good reasons
why it should be so.
2. Try [C is a funny language!]:
int x;
x=1.5;
if (x == 1.5) // false
--------------------------------
float x;
x = 1.00000001;
if (x != 1.00000001) printf ("oops!\n");
>> In fact assignment (semantic of) has nothing to do with equality. You may
>> have incomparable objects which can be assigned. You may have comparable
>> objects that cannot be assigned. You may have objects which have several
>> different semantics for assignment (deep/shallow copy/reference) and
>> equality (distance/set equality etc).
>
>That's really all irrelevant to the main point here. If you have two
>different objects A and B of the SAME type,
What is for two types to be SAME? It is not an easy question as one
might think.
> then
>
>someclass A, B;
>A = B;
>if ( A == B ) ... // better be true!
But then if you would insist that it should be so in strict
mathematical set-theoretic sense, I would derive from that, that also
A'Address = B'Address -- better be true!
If A and B are SAME then there should be no way to distingush them.
From programming point of view it has in most cases no sense [however,
see LSP]. "==" is not equality it only models one of many possible.
>If this doesn't evaluate to true, you have goofy code. Yes, I realize
>that asignment can be overloaded in C++ in all kinds of ways, but
>that's really a distraction. Your claim that "assignment has nothing
>to do with equality" is just plain wrong. Nothing to do with it? Give
>me a break!
You can start to define what is equality of two fuzzy sets. What is
equality of two floating-point numbers. What is equality of two remote
servers. What is equality of two people. Go on.
---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de
next prev parent reply other threads:[~2002-06-19 12:37 UTC|newest]
Thread overview: 188+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-06-14 7:21 status of Ada STL? Russ
2002-06-14 16:29 ` Stephen Leake
2002-06-14 18:44 ` Ted Dennison
2002-06-14 20:34 ` Ehud Lamm
2002-06-15 18:52 ` Russ
2002-06-16 2:42 ` David Marceau
2002-06-16 8:07 ` Pascal Obry
2002-06-16 18:23 ` Russ
2002-06-16 19:01 ` Pascal Obry
2002-06-16 19:04 ` Vinzent Hoefler
2002-06-17 1:59 ` Jeffrey Carter
2002-06-17 6:48 ` Russ
2002-06-17 7:04 ` Dale Stanbrough
2002-06-18 6:16 ` Russ
2002-06-19 1:07 ` Dale Stanbrough
2002-06-17 9:38 ` chris.danx
2002-06-17 15:53 ` Ted Dennison
2002-06-18 7:52 ` Russ
2002-06-18 10:57 ` chris.danx
2002-06-18 14:38 ` Robert A Duff
2002-06-18 16:19 ` Brian Rogoff
2002-06-18 17:12 ` Frank J. Lhota
2002-06-18 18:03 ` Brian Rogoff
2002-06-18 19:24 ` Frank J. Lhota
2002-06-18 19:41 ` Brian Rogoff
2002-06-25 0:02 ` Steven Deller
2002-06-25 1:24 ` Yet another assignment variation (was Re: status of Ada STL?) Dale Stanbrough
2002-06-25 12:53 ` Frank J. Lhota
2002-06-25 17:48 ` Georg Bauhaus
2002-06-26 3:13 ` Robert A Duff
2002-06-18 19:03 ` status of Ada STL? Robert A Duff
2002-06-18 19:54 ` Brian Rogoff
2002-06-18 21:09 ` Robert A Duff
2002-06-18 23:36 ` Brian Rogoff
2002-06-19 1:37 ` Robert A Duff
2002-06-19 16:25 ` Brian Rogoff
2002-06-19 18:53 ` Robert A Duff
2002-06-19 20:23 ` Brian Rogoff
2002-06-19 3:57 ` Russ
2002-06-18 21:55 ` Dmitry A.Kazakov
2002-06-19 5:32 ` Russ
2002-06-19 12:37 ` Dmitry A. Kazakov [this message]
2002-06-20 6:50 ` Russ
2002-06-20 12:21 ` Ted Dennison
2002-06-20 21:42 ` Dmitry A.Kazakov
2002-06-20 18:20 ` Russ
2002-06-21 10:27 ` Dmitry A. Kazakov
2002-06-20 18:21 ` Russ
2002-06-20 19:09 ` Russ
2002-06-17 17:16 ` Pascal Obry
2002-06-18 5:27 ` Russ
2002-06-17 17:17 ` Pascal Obry
2002-06-17 21:40 ` Vinzent Hoefler
2002-06-17 5:20 ` Russ
2002-06-17 8:22 ` chris.danx
2002-06-17 14:00 ` Frank J. Lhota
2002-06-17 15:57 ` Marin David Condic
2002-06-18 6:12 ` Russ
2002-06-18 8:16 ` chris.danx
2002-06-18 14:52 ` Robert A Duff
2002-06-18 16:02 ` Pascal Obry
2002-06-18 16:54 ` Hyman Rosen
2002-06-18 22:58 ` Jacob Sparre Andersen
2002-06-18 19:09 ` Robert A Duff
[not found] ` <ud6uolglz.fsf@w <wccsn3kxv3g.fsf@shell01.TheWorld.com>
2002-06-19 8:09 ` Pascal Obry
2002-06-19 3:04 ` Russ
2002-06-19 16:40 ` Hyman Rosen
2002-06-19 18:07 ` Brian Rogoff
2002-06-18 9:37 ` Fraser Wilson
2002-06-18 15:45 ` Hyman Rosen
2002-06-19 16:55 ` Robert I. Eachus
2002-06-19 19:13 ` Robert A Duff
2002-06-20 7:43 ` Dmitry A.Kazakov
2002-06-22 22:05 ` Robert I. Eachus
2002-06-17 21:40 ` Vinzent Hoefler
2002-06-18 15:05 ` Robert A Duff
2002-06-18 22:36 ` Vinzent Hoefler
2002-06-19 12:45 ` Dmitry A. Kazakov
2002-06-19 14:35 ` Marin David Condic
2002-06-21 11:03 ` Dmitry A. Kazakov
2002-06-21 16:58 ` Mark Biggar
2002-06-22 23:23 ` Dmitry A.Kazakov
2002-06-27 3:00 ` David Thompson
2002-06-28 13:36 ` Marin David Condic
2002-06-30 4:05 ` Russ
2002-06-30 13:50 ` Ted Dennison
2002-07-01 13:12 ` Marin David Condic
2002-07-02 19:56 ` Robert A Duff
[not found] ` <bebbba07.0206292005.45ad915a@p <wcc4rfhj43l.fsf@shell01.TheWorld.com>
2002-07-02 20:40 ` Pat Rogers
2002-06-18 15:21 ` Robert A Duff
2002-06-19 0:34 ` tmoran
2002-06-19 2:55 ` Russ
2002-06-19 4:53 ` Ted Dennison
2002-06-19 8:21 ` Pascal Obry
2002-06-19 14:52 ` Stephen Leake
2002-06-20 1:45 ` SteveD
2002-06-20 2:01 ` Ted Dennison
2002-06-16 20:01 ` Pascal Obry
2002-06-17 5:29 ` Russ
2002-06-16 23:02 ` Ted Dennison
2002-06-17 5:07 ` Russ
2002-06-17 14:03 ` Frank J. Lhota
2002-06-17 14:11 ` Ted Dennison
2002-06-18 5:55 ` Russ
2002-06-18 14:30 ` Ted Dennison
2002-06-18 15:14 ` Marin David Condic
2002-06-19 14:19 ` Ted Dennison
2002-06-19 16:05 ` Marin David Condic
2002-06-19 5:58 ` Russ
2002-06-19 14:35 ` Ted Dennison
2002-06-20 7:06 ` Russ
2002-06-20 12:27 ` Ted Dennison
2002-06-20 23:22 ` Russ
2002-06-21 2:00 ` Ted Dennison
2002-06-22 4:28 ` Russ
2002-06-22 15:05 ` Ted Dennison
2002-06-21 8:48 ` Ian Wild
2002-06-22 4:54 ` Russ
2002-06-20 22:47 ` Russ
2002-06-21 0:43 ` Ted Dennison
2002-06-22 4:05 ` Russ
2002-06-22 14:41 ` Jano
2002-06-22 20:27 ` Ted Dennison
2002-06-21 13:12 ` Marin David Condic
2002-06-24 8:29 ` Russ
2002-06-24 20:19 ` Chad R. Meiners
2002-06-18 22:36 ` Vinzent Hoefler
2002-06-18 22:42 ` Ed Falis
2002-06-19 0:07 ` Vinzent Hoefler
2002-06-19 0:07 ` Vinzent Hoefler
2002-06-17 22:37 ` Dmitry A.Kazakov
2002-06-17 14:09 ` Frank J. Lhota
2002-06-18 21:40 ` Dmitry A.Kazakov
2002-06-18 16:04 ` Robert A Duff
2002-06-18 16:37 ` Pascal Obry
2002-06-18 18:56 ` Robert A Duff
2002-06-18 22:20 ` Pascal Obry
2002-06-19 12:53 ` Dmitry A. Kazakov
2002-06-19 3:37 ` Russ
2002-06-19 8:31 ` Pascal Obry
2002-06-20 7:58 ` Russ
2002-06-20 20:34 ` Pascal Obry
2002-06-21 4:07 ` Russ
2002-06-17 15:33 ` Marin David Condic
2002-06-18 10:28 ` Adrian Hoe
2002-06-19 7:58 ` Ole-Hjalmar Kristensen
2002-06-19 13:55 ` Marin David Condic
2002-06-19 13:52 ` Marin David Condic
2002-09-18 15:23 ` Matthew Heaney
2002-09-19 12:11 ` Marin David Condic
2002-09-19 14:13 ` Hyman Rosen
2002-09-20 12:24 ` Marin David Condic
2002-09-22 7:22 ` Kevin Cline
2002-09-23 13:55 ` Hyman Rosen
2002-09-19 19:42 ` Randy Brukardt
2002-09-20 12:38 ` Marin David Condic
2002-09-27 21:21 ` Michael Bode
2002-09-27 22:11 ` Pat Rogers
2002-09-28 13:25 ` Marin David Condic
2002-09-28 14:52 ` Pat Rogers
2002-09-28 15:18 ` Martin Dowie
2002-09-29 18:02 ` Marin David Condic
2002-09-29 19:02 ` Jeffrey Carter
2002-09-30 1:36 ` Marin David Condic
2002-10-02 22:17 ` Matthew Heaney
2002-09-28 17:25 ` Richard Riehle
2002-09-30 17:12 ` Marin David Condic
2002-10-01 18:41 ` Randy Brukardt
2002-10-02 8:38 ` Jean-Pierre Rosen
2002-10-02 12:43 ` Marin David Condic
2002-10-02 14:26 ` Jean-Pierre Rosen
2002-10-02 12:30 ` Marin David Condic
2002-06-18 1:56 ` SteveD
2002-06-18 14:12 ` Robert A Duff
2002-06-18 14:28 ` chris.danx
2002-06-18 15:59 ` Pascal Obry
2002-06-18 18:58 ` Robert A Duff
2002-06-18 19:58 ` Randy Brukardt
2002-06-19 14:07 ` Marin David Condic
2002-06-19 2:19 ` SteveD
2002-06-18 11:40 ` Colin Paul Gloster
2002-06-20 15:15 ` Colin Paul Gloster
2002-06-18 19:34 ` Mike Silva
2002-06-25 16:31 ` Kevin Cline
2002-06-14 20:34 ` Dan Andreatta
-- strict thread matches above, loose matches on Subject: below --
2002-06-17 11:05 Grein, Christoph
2002-06-18 5:36 ` Russ
2002-06-26 10:50 Grein, Christoph
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