From: jhd@herold.franken.de (Joachim Durchholz)
Subject: Re: Interesting but sensitive topic to discuss (HELP: - OOP and CASE t
Date: 1996/11/08
Date: 1996-11-08T00:00:00+00:00 [thread overview]
Message-ID: <6KVOxOkk3RB@herold.franken.de> (raw)
In-Reply-To: 32813322.41C6@kyebek3.kjist.ac.kr
alovejoy@concentric.net wrote 08.11.96:
> > I think this is a bit misleading.
Seems I got mislead my self a bit :)
> execution of a program. And in a Self program, classes never exist at all
> (not even in the program text).
Well, I don't know Self (or any other prototype language), so I'm a bit
bewildered about what you say about this statement.
Could anybody post a short characterisation of prototype languages?
> > We don't specify a single objects when
> > writing code for a class; instead, we specify the behaviour of a set of
> > objects, of which there may be none, one, or an unlimited number present
> > at run-time.
>
> To the extent that this is true, this is an artifact of using classes as an
> abstraction mechanism to specify the behavior of objects.
I don't think it is too artificial to define a class, even if it is for a
single object. At least not if the class specification isn't longer or
more complicated than the specification for the single object.
I do see some overhead in that it is necessary to declare an attribute
that is instantiated with the constructor of the class. Given the size of
class texts, I doubt that this overhead is a problem.
> > > Class inheritance is an abstraction mechanism for code sharing.
> >
> > It is much more. It is a mechanism for specifying similarities, and in
> > this respect goes far beyond mere code sharing.
>
> A class specifies the internal mechanisms of an object. Class inheritance
> therefore specifies the commonality of implementation mechanisms.
> ...
> This is actually what I was trying to get at
> in saying that "class inheritance is an abstraction mechanism for code
> [implementation mechanism] sharing."
Not in all cases. Most OO languages have abstract/virtual/deferred classes
that primarily serve to specify external behaviour, not implementation.
I definitely agree that inheritance can be used for code sharing, but it
is also useful for object classification.
> The type/interface hierarchy is an important topic in design, and hence is
> an important issue that should be addressed by a design methodology.
> ...
Agreed. (As with the rest of your post :)
-Joachim
--
Looking for a new job. Resume available on request. WWW version of resume
available under http://www.franken.de/users/herold/jhd/resume/index.html
next prev parent reply other threads:[~1996-11-08 0:00 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
1996-11-06 0:00 Interesting but sensitive topic to discuss (HELP: - OOP and CASE tools) Dong Oh Kim
1996-11-06 0:00 ` Paul_Gover
1996-11-06 0:00 ` Jan Steinman
1996-11-07 0:00 ` Paul_Gover
1996-11-12 0:00 ` Robert C. Martin
1996-11-12 0:00 ` Alan Lovejoy
1996-11-12 0:00 ` Snowball
1996-11-15 0:00 ` Soren Skogstad Nielsen
1996-11-28 0:00 ` Piercarlo Grandi
1996-11-28 0:00 ` Piercarlo Grandi
1996-11-06 0:00 ` Alan Lovejoy
1996-11-07 0:00 ` Piercarlo Grandi
1996-11-10 0:00 ` drs
1996-11-12 0:00 ` Piercarlo Grandi
1996-11-10 0:00 ` Vlastimil Adamovsky
1996-11-11 0:00 ` Piercarlo Grandi
1996-11-11 0:00 ` Anthony Menio
1996-11-18 0:00 ` Piercarlo Grandi
1996-11-20 0:00 ` Anthony Menio
1996-11-27 0:00 ` Piercarlo Grandi
1996-11-12 0:00 ` Anthony Menio
1996-11-18 0:00 ` Piercarlo Grandi
1996-11-19 0:00 ` Anthony Menio
1996-11-27 0:00 ` Piercarlo Grandi
1996-11-11 0:00 ` Daniel Drasin
1996-11-12 0:00 ` Anthony Menio
1996-11-08 0:00 ` Paul_Gover
1996-11-08 0:00 ` Ell
1996-11-08 0:00 ` Alan Lovejoy
1996-11-13 0:00 ` Ell
1996-11-08 0:00 ` Alan Lovejoy
[not found] ` <6KZQfjK-3RB@herold.franken.de>
1996-11-10 0:00 ` Interesting but sensitive topic to discuss (HELP: - OOP and CASE t Chris
1996-11-10 0:00 ` Vlastimil Adamovsky
1996-11-11 0:00 ` Interesting but sensitive topic to discuss (HELP: - OOP and CASE tools) Bill Gooch
1996-11-12 0:00 ` Jan Steinman
1996-11-12 0:00 ` Alan Lovejoy
1996-11-13 0:00 ` Nick Thurn
1996-11-13 0:00 ` Alan Lovejoy
1996-11-14 0:00 ` Nick Thurn
1996-11-12 0:00 ` Alan Lovejoy
1996-11-13 0:00 ` Nick Thurn
1996-11-13 0:00 ` Ell
1996-11-14 0:00 ` Bill Gooch
1996-11-19 0:00 ` Tim Ottinger
1996-11-10 0:00 ` vlad
1996-11-12 0:00 ` Robert C. Martin
1996-11-12 0:00 ` Alan Lovejoy
1996-11-14 0:00 ` David N. Smith
1996-11-14 0:00 ` Bill Gooch
1996-11-20 0:00 ` Robert C. Martin
1996-11-20 0:00 ` Robert Dewar
1996-11-20 0:00 ` Michael Malak
1996-11-20 0:00 ` Robert Dewar
1996-11-26 0:00 ` Tucker Taft
1996-12-03 0:00 ` Robert C. Martin
1996-12-08 0:00 ` Tucker Taft
1996-11-06 0:00 ` Snowball
1996-11-13 0:00 ` Peter Pflaum
1996-11-13 0:00 ` David N. Smith
1996-11-07 0:00 ` Interesting but sensitive topic to discuss (HELP: - OOP and CASE t Joachim Durchholz
1996-11-08 0:00 ` Richard A. O'Keefe
1996-11-09 0:00 ` Piercarlo Grandi
1996-11-13 0:00 ` Richard A. O'Keefe
1996-11-27 0:00 ` Piercarlo Grandi
1996-11-08 0:00 ` Nick Thurn
1996-11-08 0:00 ` Alan Lovejoy
1996-11-11 0:00 ` Nick Thurn
1996-11-11 0:00 ` Paul_Gover
1996-11-11 0:00 ` Anthony Menio
1996-11-11 0:00 ` Interesting but sensitive topic to discuss (HELP: - OOP and CASE tools) David N. Smith
1996-11-12 0:00 ` Anthony Menio
1996-11-08 0:00 ` Joachim Durchholz [this message]
1996-11-12 0:00 ` Interesting but sensitive topic to discuss (HELP: - OOP and CASE t Alaric B. Williams
1996-11-13 0:00 ` Richard A. O'Keefe
1996-11-08 0:00 ` Alan Lovejoy
1996-11-08 0:00 ` Jon S Anthony
1996-11-11 0:00 ` Interesting but sensitive topic to discuss (HELP: - OOP and CASE tools) Cesar A. Gonzalez Perez
1996-11-12 0:00 ` Interesting but sensitive topic to discuss (HELP: - OOP and CASE t Joachim Durchholz
1996-11-20 0:00 ` Piercarlo Grandi
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