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From: schlegel@pella.informatik.uni-rostock.de (Juergen Schlegelmilch)
Subject: Re: To overload or not to overload (was Eiffel and Java + Ada dispatching)
Date: 1996/11/07
Date: 1996-11-07T00:00:00+00:00	[thread overview]
Message-ID: <slrn5836sh.rl.schlegel@pella.informatik.uni-rostock.de> (raw)
In-Reply-To: E0HKx9.8E3@syd.csa.com.au


In article <E0HKx9.8E3@syd.csa.com.au>, Don Harrison wrote:
>
>However, in relation to Eiffel, I'm saying that it has no *need* of an 
>overloading mechanism because it is redundant due to the availability of 
>covariance. An operation which you might choose to implement in Ada by 
>overloading an inherited one (because they do the same job), you would 
>implement in Eiffel as an overriding operation because it belongs in the 
>same inheritance hierarchy (according to Eiffel's scheme of things).

Hm, being not too familiar with Ada, I may be wrong, but in the subclass
you have both operations available, while with Eiffel's redefinition you
only have the redefined but not the inherited (unless you inherited once,
but then you have to rename). Thus, in a piece of code where an operation 
is applied to arguments suitable only for the inherited version, Eiffel 
will signal a type error (system validity or by runtime crash :-), while Ada 
will use the inherited (overloaded) version.

So, covariant redefinition is not a mechanism to implement/simulate 
overloading.

  Juergen Schlegelmilch

-- 
+-----------------------------------------------------------------------------+
 Dipl.-Inf. Juergen Schlegelmilch                 University of Rostock
 email: schlegel@Informatik.Uni-Rostock.de        Computer Science Department
 http://www.informatik.uni-rostock.de/~schlegel   Database Research Group 
 Tel: ++49 381 498 3402                           18051 Rostock 
 Fax: ++49 381 498 3426                           Germany
+-----------------------------------------------------------------------------+





  reply	other threads:[~1996-11-07  0:00 UTC|newest]

Thread overview: 162+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1996-10-27  0:00 Eiffel and Java Vincent WEBER
1996-10-27  0:00 ` Jean-Michel P. Decombe
1996-10-28  0:00   ` Robert Dewar
1996-10-31  0:00     ` Doug Marker
1996-10-28  0:00   ` Alexandre Oliva
1996-10-28  0:00   ` David Hanley
1996-10-28  0:00     ` Matt Kennel
1996-10-29  0:00   ` Chris Trimble
1996-10-31  0:00     ` Doug Marker
1996-10-31  0:00   ` David Bennett
1996-10-28  0:00 ` Larry Kilgallen
1996-10-30  0:00   ` Ronald Cole
1996-10-28  0:00 ` Matthew Heaney
1996-10-29  0:00   ` Vincent WEBER
1996-10-31  0:00     ` James McKim
1996-11-01  0:00       ` Matthew Heaney
1996-11-04  0:00         ` James McKim
1996-10-30  0:00   ` Don Harrison
1996-10-31  0:00     ` James McKim
1996-11-04  0:00       ` Don Harrison
1996-11-23  0:00       ` Van Snyder
1996-10-30  0:00   ` Jon S Anthony
1996-11-01  0:00     ` Eiffel and Java + Ada dispatching Jean-Marc Jezequel
1996-10-31  0:00   ` Eiffel and Java Joachim Durchholz
1996-11-01  0:00   ` Norman H. Cohen
1996-11-02  0:00   ` Jon S Anthony
1996-11-02  0:00   ` Eiffel and Java + Ada dispatching Jon S Anthony
1996-11-03  0:00   ` Eiffel and Java Joachim Durchholz
1996-11-05  0:00   ` Norman H. Cohen
1996-10-29  0:00 ` Don Harrison
1996-10-29  0:00   ` Fergus Henderson
1996-10-30  0:00     ` Don Harrison
1996-10-30  0:00       ` Fergus Henderson
1996-10-31  0:00     ` David L. Shang
1996-11-01  0:00       ` Matt Kennel
1996-11-04  0:00         ` David L. Shang
1996-11-05  0:00           ` Matt Kennel
1996-11-06  0:00             ` David L. Shang
1996-11-04  0:00       ` Robert I. Eachus
1996-11-01  0:00     ` Jon S Anthony
1996-11-02  0:00       ` Fergus Henderson
1996-11-04  0:00       ` David L. Shang
1996-11-05  0:00         ` Jon S Anthony
1996-11-02  0:00     ` Darko BUDOR
1996-11-02  0:00       ` Fergus Henderson
1996-11-03  0:00         ` Darko BUDOR
1996-11-03  0:00         ` Matt Kennel
1996-11-03  0:00     ` Jon S Anthony
1996-11-03  0:00     ` Matthias Ernst
1996-11-05  0:00     ` Jon S Anthony
1996-11-10  0:00     ` Marcos F. F. de Macedo
1996-11-11  0:00       ` David L. Shang
1996-11-12  0:00         ` Fergus Henderson
1996-11-12  0:00           ` David L. Shang
1996-11-12  0:00             ` David L. Shang
1996-11-16  0:00             ` Fergus Henderson
1996-11-18  0:00               ` David L. Shang
1996-11-18  0:00             ` Kai Quale
1996-11-18  0:00               ` David L. Shang
1996-11-25  0:00                 ` Kai Quale
1996-11-15  0:00         ` Paul Johnson
1996-11-12  0:00       ` Alexander Asteroth
1996-11-11  0:00         ` Marcos F. F. de Macedo
1996-11-12  0:00         ` Benedict A. Gomes
1996-11-12  0:00         ` Matt Kennel
1996-10-29  0:00   ` Eiffel and Java + Ada dispatching Vincent WEBER
1996-10-30  0:00     ` Don Harrison
1996-10-30  0:00       ` Jon S Anthony
1996-10-30  0:00     ` Jean-Marc Jezequel
1996-11-01  0:00       ` Don Harrison
1996-11-01  0:00       ` Joachim Durchholz
1996-10-30  0:00   ` Robert I. Eachus
1996-10-30  0:00   ` Jon S Anthony
1996-11-04  0:00     ` Don Harrison
1996-11-04  0:00       ` C to Ada Ali Mirhosseini
1996-11-04  0:00         ` Robert Dewar
1996-11-04  0:00         ` Matthew Daniel
1996-11-05  0:00       ` Eiffel and Java + Ada dispatching Jon S Anthony
1996-11-05  0:00         ` Don Harrison
1996-11-06  0:00           ` Jon S Anthony
1996-10-30  0:00   ` Eiffel and Java David Petrie Stoutamire
1996-10-31  0:00   ` Eiffel and Java + Ada dispatching Jon S Anthony
1996-11-01  0:00     ` Jean-Marc Jezequel
     [not found]     ` <E06F2B.Az7@syd.csa.com.au>
1996-11-01  0:00       ` Jon S Anthony
1996-11-04  0:00         ` Don Harrison
1996-11-05  0:00           ` Jon S Anthony
1996-11-02  0:00       ` Robert Dewar
1996-11-04  0:00         ` Norman H. Cohen
1996-11-05  0:00         ` Don Harrison
1996-11-05  0:00           ` Robb Nebbe
1996-11-06  0:00             ` Jean-Marc Jezequel
1996-11-07  0:00               ` Robb Nebbe
1996-11-06  0:00             ` To overload or not to overload (was Eiffel and Java + Ada dispatching) Don Harrison
1996-11-06  0:00               ` Robb Nebbe
1996-11-07  0:00                 ` Don Harrison
1996-11-07  0:00                   ` Juergen Schlegelmilch [this message]
1996-11-08  0:00                     ` Don Harrison
1996-11-08  0:00                       ` Don Harrison
1996-11-14  0:00                         ` Jon S Anthony
1996-11-14  0:00                     ` Jon S Anthony
1996-11-07  0:00                   ` Jon S Anthony
1996-11-07  0:00                   ` Jon S Anthony
1996-11-11  0:00                     ` Don Harrison
1996-11-08  0:00                   ` bill.williams
1996-11-11  0:00                     ` Don Harrison
1996-11-07  0:00                 ` Norman H. Cohen
1996-11-08  0:00             ` Eiffel and Java + Ada dispatching Robert I. Eachus
1996-11-05  0:00           ` Joachim Durchholz
1996-11-06  0:00           ` Robert I. Eachus
1996-11-08  0:00             ` Don Harrison
1996-11-08  0:00               ` Jon S Anthony
1996-11-08  0:00               ` Robert A Duff
1996-11-12  0:00                 ` Don Harrison
1996-11-12  0:00                   ` Robert A Duff
1996-11-13  0:00                     ` Don Harrison
1996-11-13  0:00                       ` Jon S Anthony
1996-11-15  0:00                         ` Don Harrison
1996-11-19  0:00                           ` Jon S Anthony
1996-11-20  0:00                             ` Don Harrison
1996-11-13  0:00                       ` Robert A Duff
1996-11-14  0:00                         ` Don Harrison
1996-11-12  0:00                   ` Joachim Durchholz
1996-11-15  0:00                     ` Richard Riehle
1996-11-16  0:00                     ` Interfacing contracts (Was: Eiffel and Java + Ada dispatching) Geert Bosch
1996-11-17  0:00                       ` Robert A Duff
1996-11-14  0:00               ` Eiffel and Java + Ada dispatching Robert I. Eachus
1996-11-14  0:00                 ` Robert A Duff
1996-11-15  0:00                 ` Don Harrison
1996-11-15  0:00                   ` Robert I. Eachus
1996-11-19  0:00                     ` Don Harrison
1996-11-18  0:00                       ` Vincent Celier
1996-11-22  0:00                         ` Don Harrison
1996-11-19  0:00                 ` Jon S Anthony
1996-11-15  0:00               ` portmanteau (was Re: Eiffel and Java + Ada dispatching) Robert I. Eachus
1996-11-07  0:00           ` Eiffel and Java + Ada dispatching Jon S Anthony
1996-11-07  0:00           ` Robb Nebbe
1996-11-12  0:00           ` Jon S Anthony
1996-10-31  0:00   ` Joachim Durchholz
1996-11-01  0:00   ` Eiffel and Java Matthias Ernst
1996-11-01  0:00     ` William Clodius
1996-11-01  0:00     ` Benedict A. Gomes
1996-11-02  0:00   ` Eiffel and Java + Ada dispatching Jon S Anthony
1996-11-02  0:00   ` Jon S Anthony
1996-11-04  0:00   ` Eiffel and Java Robert I. Eachus
1996-10-30  0:00 ` Jon S Anthony
1996-11-01  0:00   ` Don Harrison
1996-11-01  0:00     ` Jon S Anthony
1996-11-07  0:00       ` Marcos F. F. de Macedo
1996-11-11  0:00         ` Ian Joyner
1996-11-12  0:00         ` Don Harrison
1996-11-13  0:00           ` Norman H. Cohen
1996-11-15  0:00             ` Don Harrison
1996-11-14  0:00           ` Jon S Anthony
1996-11-15  0:00             ` Don Harrison
1996-11-19  0:00               ` Jon S Anthony
1996-11-21  0:00                 ` Don Harrison
1996-11-12  0:00     ` Jon S Anthony
1996-10-31  0:00 ` Joachim Durchholz
1996-11-01  0:00 ` Jon S Anthony
1996-11-02  0:00 ` Jon S Anthony
1996-11-03  0:00 ` Eiffel and Java + Ada dispatching Joachim Durchholz
1996-11-04  0:00 ` Eiffel and Java Richard A. O'Keefe
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