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From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Desirability of C++
Date: 2000/05/03
Date: 2000-05-03T00:00:00+00:00	[thread overview]
Message-ID: <wcc7ldblluu.fsf@world.std.com> (raw)
In-Reply-To: 8eonat$sqj3@ftp.kvaerner.com

"Tarjei T. Jensen" <tarjei.jensen@kvaerner.com> writes:

> Robert A Duff wrote
> >The designer of Ada.Strings.Unbounded (Ben Brosgol) considered doing it
> >as in the above-mentioned package.  The reason not to do it that way is
> >documented in the AARM -- assignment statements don't work properly.
> >That is, if you assign a 5-character string (whose max length is 80) to
> >a string variable whose max is 120, you will get a Constraint_Error,
> >even though 5 characters fit nicely in 120.  JPR points this out in the
> >documentation for his package, and he provides a procedure for copying
> >strings, which should be used instead of assignment.
> 
> A more natural conclusion would be that there was a language problem. 

That *was* the conclusion.

>...In order
> to fix it one would either have to make the compiler aware of strings, make it
> possible to tell the compiler about what controls the size of a variable sized
> object like a counted string or make it possible to override the assignment
> operator.

All of those changes were considered too big.

> It would be convenient to be able to tell the compiler how to access the
> character array in string types other than the ordinary ada string. It would
> save a lot of copying. And it should be quite safe since routines that use the
> ordinary string types cannot change the length of the string.
> 
> >Apparently, Turbo Pascal actually makes assignment work, which is
> >obviously preferable to either of the above Ada alternatives.  On the
> >other hand, there are lots of *other* things wrong with the Turbo Pascal
> >solution, which have been pointed out in this thread.
> 
> I think it was the ucsd-pascal people who first got it right.

They got some things right, and some things wrong.  For example, the
limit of 255 characters is pretty annoying -- even in the bad old days
of smaller memories.

> C has only one string type.

C doesn't even have a character type, much less a string type!  It has
an integer type called char, it has pointers to [arrays of] those, it
has character literal and string literal notations, it has a
nul-termination convention, and a few library routines.  But it doesn't
have the most basic things you want, such as carrying the length with
the string, comparison operators, assignment operator.

>... It works reasonably well. Probably the most
> important "feature" is that everything is by reference, so there is no problems
> with strings of different sizes, etc.

- Bob




  parent reply	other threads:[~2000-05-03  0:00 UTC|newest]

Thread overview: 176+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2000-02-04  0:00 where can we get a job with ada HollymaN
2000-02-03  0:00 ` David Kristola
2000-02-04  0:00   ` EKoerber
2000-02-04  0:00     ` Ted Dennison
2000-02-04  0:00       ` Brian Rogoff
2000-02-05  0:00         ` David Kristola
2000-02-06  0:00           ` Simon Brady
2000-02-07  0:00             ` Ted Dennison
2000-02-07  0:00             ` Gareth
2000-02-07  0:00               ` Kent Paul Dolan
2000-02-07  0:00                 ` Gareth
2000-02-08  0:00                   ` Kent Paul Dolan
2000-02-11  0:00                 ` where can we ... [off topic] Nick Roberts
2000-02-07  0:00               ` where can we get a job with ada Simon Brady
2000-02-07  0:00               ` Ted Dennison
2000-02-12  0:00               ` Jeff Carter
2000-02-28  0:00             ` Florian Weimer
2000-02-29  0:00               ` Ted Dennison
2000-03-01  0:00               ` Wes Groleau
2000-03-04  0:00               ` Robert B. Love 
2000-03-05  0:00                 ` Ted Dennison
2000-03-05  0:00                 ` Ada on International Space Station (Re: where can we get a job with ada) Vladimir Olensky
2000-03-08  0:00                   ` Robert B. Love 
2000-03-08  0:00                     ` Vladimir Olensky
2000-03-08  0:00                     ` Jean St-Pierre
2000-04-03  0:00                   ` Andrew Thomas Wilson
2000-04-12  0:00                     ` David Hoffman
2000-04-13  0:00                       ` Robert B. Love 
2000-04-14  0:00                         ` Desirability of C++ (was Re: Ada on International Space Station (Re: where can we get a job with ada)) David Kristola
2000-04-14  0:00                           ` Wes Groleau
2000-04-14  0:00                             ` Desirability of C++ Stanley R. Allen
2000-04-14  0:00                               ` Marin D. Condic
2000-04-15  0:00                                 ` Tarjei T. Jensen
2000-04-15  0:00                                   ` Marin D. Condic
2000-04-15  0:00                                     ` Tarjei T. Jensen
2000-04-17  0:00                                   ` Alfred Hilscher
2000-04-17  0:00                                     ` Gautier
2000-04-18  0:00                                       ` Pascal Obry
2000-04-18  0:00                                       ` Tarjei T. Jensen
2000-04-18  0:00                                         ` Gautier
2000-04-28  0:00                                         ` Richard D Riehle
2000-05-02  0:00                                           ` Tarjei T. Jensen
2000-04-23  0:00                                       ` David Kristola
2000-04-18  0:00                                     ` Tarjei T. Jensen
2000-04-17  0:00                                 ` Alfred Hilscher
2000-04-17  0:00                                   ` Marin D. Condic
2000-04-17  0:00                                     ` Gary Scott
2000-04-28  0:00                               ` Richard D Riehle
2000-04-30  0:00                                 ` Robert B. Love 
2000-05-01  0:00                                   ` Richard D Riehle
2000-05-01  0:00                                     ` E. Robert Tisdale
2000-04-30  0:00                                       ` Keith Thompson
2000-05-01  0:00                                         ` E. Robert Tisdale
2000-05-01  0:00                                           ` Keith Thompson
2000-05-01  0:00                                       ` Ted Dennison
2000-05-01  0:00                                       ` Gautier
2000-05-01  0:00                                         ` E. Robert Tisdale
2000-05-01  0:00                                           ` Pat Rogers
2000-05-01  0:00                                             ` E. Robert Tisdale
2000-05-01  0:00                                               ` Pat Rogers
2000-05-01  0:00                                                 ` Michael P. Walsh
2000-05-01  0:00                                                   ` Pat Rogers
2000-05-01  0:00                                                     ` E. Robert Tisdale
2000-05-02  0:00                                                       ` Bill Greene
2000-05-01  0:00                                             ` David Starner
2000-05-01  0:00                                               ` David Starner
2000-05-01  0:00                                               ` Florian Weimer
2000-05-01  0:00                                                 ` tmoran
2000-05-01  0:00                                                 ` Lionel Draghi
2000-05-02  0:00                                                   ` Florian Weimer
2000-05-01  0:00                                                 ` David Starner
2000-05-01  0:00                                                 ` Ted Dennison
2000-05-01  0:00                                                   ` Tarjei Tj�stheim Jensen
2000-05-01  0:00                                                     ` Ted Dennison
2000-05-02  0:00                                                       ` Preben Randhol
2000-05-02  0:00                                                       ` Florian Weimer
2000-05-02  0:00                                                   ` Application in Ada (was Desirability of C++) Jean-Pierre Rosen
2000-05-02  0:00                                                     ` Ted Dennison
2000-05-02  0:00                                                       ` Jean-Pierre Rosen
2000-05-03  0:00                                                       ` Tarjei Tj�stheim Jensen
2000-05-03  0:00                                                         ` Ted Dennison
2000-05-01  0:00                                               ` Desirability of C++ Pat Rogers
2000-05-01  0:00                                                 ` Ted Dennison
2000-05-01  0:00                                                   ` E. Robert Tisdale
2000-05-01  0:00                                                     ` Pat Rogers
2000-05-01  0:00                                                     ` Gautier
2000-05-01  0:00                                         ` Marin D. Condic
2000-05-01  0:00                                         ` Hyman Rosen
2000-05-01  0:00                                           ` Tarjei Tj�stheim Jensen
2000-05-01  0:00                                             ` tmoran
2000-05-02  0:00                                               ` Tarjei T. Jensen
2000-05-02  0:00                                                 ` Preben Randhol
2000-05-02  0:00                                                   ` Strings TP/Ada (was Desirability of C++) Gautier
2000-05-02  0:00                                                   ` Desirability of C++ Keith Thompson
2000-05-03  0:00                                                   ` Tarjei T. Jensen
2000-05-03  0:00                                                     ` Robert A Duff
2000-05-02  0:00                                               ` Gautier
2000-05-02  0:00                                                 ` Jean-Pierre Rosen
2000-05-02  0:00                                                   ` Gautier
2000-05-02  0:00                                                     ` Jean-Pierre Rosen
2000-05-03  0:00                                                       ` Marin D. Condic
2000-05-03  0:00                                                         ` Jean-Pierre Rosen
2000-05-03  0:00                                                           ` Wes Groleau
2000-05-04  0:00                                                         ` Robert I. Eachus
2000-05-05  0:00                                                           ` Marin D. Condic
2000-05-03  0:00                                                       ` Robert A Duff
2000-05-03  0:00                                                         ` Jean-Pierre Rosen
2000-05-02  0:00                                                     ` Robert A Duff
2000-05-03  0:00                                                       ` Robert I. Eachus
2000-05-03  0:00                                                         ` Robert A Duff
2000-05-04  0:00                                                           ` Robert I. Eachus
2000-05-03  0:00                                                       ` Tarjei T. Jensen
2000-05-03  0:00                                                         ` Pascal Obry
2000-05-03  0:00                                                           ` Paul Graham
2000-05-03  0:00                                                             ` Pascal Obry
2000-05-03  0:00                                                               ` Paul Graham
2000-05-03  0:00                                                                 ` Robert A Duff
2000-05-04  0:00                                                               ` Ole-Hjalmar Kristensen
2000-05-04  0:00                                                                 ` Preben Randhol
2000-05-04  0:00                                                                   ` Ole-Hjalmar Kristensen
2000-05-04  0:00                                                                     ` Preben Randhol
2000-05-04  0:00                                                                 ` Pascal Obry
2000-05-05  0:00                                                             ` Gautier
2000-05-04  0:00                                                           ` Ole-Hjalmar Kristensen
2000-05-03  0:00                                                         ` Robert A Duff [this message]
2000-05-03  0:00                                                           ` Delphi Strings (was Re: Desirability of C++) Ray Blaak
2000-05-02  0:00                                               ` Desirability of C++ Al Christians
2000-05-02  0:00                                             ` Gautier
2000-05-01  0:00                                           ` Gautier
2000-05-01  0:00                                             ` Brian Rogoff
2000-05-02  0:00                                               ` Gautier
2000-05-02  0:00                                             ` Ole-Hjalmar Kristensen
2000-05-02  0:00                                           ` Richard D Riehle
2000-05-01  0:00                                       ` Tarjei Tj�stheim Jensen
2000-05-01  0:00                                         ` Gautier
2000-05-01  0:00                                         ` Pascal Obry
2000-05-01  0:00                                           ` Gautier
2000-05-01  0:00                                             ` Ted Dennison
2000-05-01  0:00                                           ` Tarjei Tj�stheim Jensen
2000-05-07  0:00                                       ` ANTHONY GAIR
2000-05-07  0:00                                         ` Richard D Riehle
2000-05-07  0:00                                           ` ANTHONY GAIR
2000-05-08  0:00                                             ` Pascal Obry
2000-05-08  0:00                                               ` Ehud Lamm
2000-05-08  0:00                                                 ` Larry Kilgallen
2000-05-08  0:00                                           ` Stanley R. Allen
2000-05-09  0:00                                             ` Richard D Riehle
2000-05-08  0:00                                           ` Mario Klebsch
2000-05-08  0:00                                             ` E. Robert Tisdale
2000-05-08  0:00                                               ` Gautier
2000-05-09  0:00                                               ` Stanley R. Allen
2000-05-10  0:00                                                 ` Mario Klebsch
2000-05-10  0:00                                                 ` Alfred Hilscher
2000-05-07  0:00                                         ` Robert Dewar
2000-05-07  0:00                                         ` Hyman Rosen
2000-05-07  0:00                                           ` ANTHONY GAIR
2000-05-08  0:00                                             ` Hyman Rosen
2000-05-09  0:00                                               ` Pascal Obry
2000-05-11  0:00                                             ` wv12
2000-05-11  0:00                                               ` Frank J. Lhota
2000-05-11  0:00                                               ` Warner Bruns
2000-05-18  0:00                                                 ` Warner Bruns
2000-05-19  0:00                                                   ` ANTHONY GAIR
2000-05-24  0:00                                                   ` Richard Kenner
2000-05-18  0:00                                                 ` ANTHONY GAIR
2000-05-01  0:00                                     ` Tarjei Tj�stheim Jensen
2000-05-01  0:00                                 ` Ken Garlington
2000-04-29  0:00                         ` Ada on International Space Station (Re: where can we get a job with ada) Chris Johnston
2000-05-01  0:00                           ` Ted Dennison
2000-05-01  0:00                       ` Desirability of C++ Larry Kilgallen
     [not found]                       ` <7EA1B852F5D4D8C6.26EEE9181C8Reply-To: Kilgallen@eisner.decus.org.nospam <Ij4OaidfGTH8@eisner.decus.org>
2000-05-01  0:00                         ` E. Robert Tisdale
2000-03-22  0:00                 ` where can we get a job with ada Florian Weimer
2000-03-05  0:00               ` David Kristola
2000-02-04  0:00 ` Stanley R. Allen
2000-02-04  0:00   ` Stanley R. Allen
2000-02-06  0:00 ` David Tannen
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