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From: jamess1889@aol.com (JamesS1889)
Subject: Re: "use" clauses and Ada 95 OOP
Date: 1996/07/25
Date: 1996-07-25T00:00:00+00:00	[thread overview]
Message-ID: <4t7vev$ot9@newsbf02.news.aol.com> (raw)
In-Reply-To: EACHUS.96Jul23175154@spectre.mitre.org


In article <JSA.96Jul23220309@alexandria>, jsa@alexandria (Jon S Anthony)
writes:

>Well, this still does not answer my question, but maybe it does not
>matter.  I think I now see that the issue is that in Ada, dispatching
>is a local issue and does _not_ occur by default - rather it occurs
>for primitive ops of tagged tyes iff you pass in a "class-wide" actual
>to a controlling formal parameter.  To not dispatch you simply use an
>actual of a specific type and then the operation will be statically
>bound.  So, dispatching or not has nothing to do with qualified names.

And I actually don't know as much as I should about dispatching in C++. 
You're right, it probably doesn't matter.  I was actually talking about
syntactic analogy.  Semantically, you are right.

>In Java and C++ (with"virtual"...)  dispatching is a global issue and
>the default is to dispatch, and to not dispatch you have to explicitly
>request non-dispatching with a qualified name.  So, you appear to have
>linked up qualified name notation with explicit calls to the function
>so qualified.  OK, yes, this is different than the situation in Ada
>and notice that the use of "use" does not change the semantics of this
>only the visual appearance.

Agreed.

>I suppose the route that you would be more comfortable with then is the
>one that I mentioned in a previous post, viz., the use of abstract base
>types for any extension that provides _new_ primitive operations.  You
>then use dispatching invocations only on the abstract operation.  You
>would then typically (well I suppose) use qualified naming but since
>the operation is abstract it would not seem "funny" that it dispatched
>to wherever (based on the type indicator):

Maybe so.  It's under consideration ;-)

James Squire                                      
mailto:ja_squire@csehp3.mdc.com
MDA Avionics Tools & Processes
McDonnell Douglas Aerospace              http://www.mdc.com
Opinions expressed here are my own and NOT my company's
"Only one Earth Captain has ever survived battle with a Minbari fleet.  He
is behind me.
You are in front of me.  If you value your lives, be somewhere else!"
           -- Delenn, "Severed Dreams"




  reply	other threads:[~1996-07-25  0:00 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1996-07-17  0:00 "use" clauses and Ada 95 OOP Mitch Gart
1996-07-19  0:00 ` James A. Squire
1996-07-22  0:00   ` Stephen Schmid
1996-07-23  0:00     ` JamesS1889
1996-07-23  0:00     ` Mitch Gart
1996-07-23  0:00       ` Kevin J. Weise
1996-07-23  0:00         ` JamesS1889
1996-07-23  0:00       ` Kevin J. Weise
1996-07-23  0:00       ` Robert Dewar
1996-07-25  0:00         ` JamesS1889
1996-07-26  0:00           ` Robert A Duff
1996-07-23  0:00       ` Robert A Duff
1996-07-23  0:00     ` Laurent Guerby
1996-07-23  0:00       ` Robert A Duff
1996-07-23  0:00     ` JamesS1889
1996-07-24  0:00     ` Jon S Anthony
1996-07-24  0:00     ` Jon S Anthony
1996-07-19  0:00 ` Jon S Anthony
1996-07-19  0:00 ` Robert I. Eachus
1996-07-23  0:00   ` JamesS1889
1996-07-23  0:00     ` Robert Dewar
1996-07-24  0:00     ` Robert I. Eachus
1996-07-23  0:00   ` Robert I. Eachus
1996-07-25  0:00     ` JamesS1889 [this message]
1996-07-24  0:00   ` Jon S Anthony
1996-07-20  0:00 ` James A. Squire
1996-07-21  0:00   ` Robert A Duff
1996-07-22  0:00 ` Jon S Anthony
1996-07-23  0:00 ` Jon S Anthony
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