From: matthias_k <nospam@digitalraid.com>
Subject: Re: Classwide Parameter?
Date: Tue, 12 Oct 2004 10:01:34 +0200
Date: 2004-10-12T10:01:34+02:00 [thread overview]
Message-ID: <ckg303$dbt$00$1@news.t-online.com> (raw)
In-Reply-To: <umzyseeo5.fsf@earthlink.net>
Matthew Heaney wrote:
> matthias_k <nospam@digitalraid.com> writes:
>
>
>>Thanks for that answer. However, I'm still having problems (I have
>>rewritten the code to be in one single package now):
>>
>><snip>
>>package Graphics is
>>
>> type Shape is abstract tagged null record;
>> procedure Draw (Obj: Shape'Class);
>
>
> Get rid of this operation. It's a "class-wide" operation (like a static
> method in C++), and hence the operation isn't primitive for the type
> (and therefore doesn't dispatch).
>
>
Oha? I thought it would be analogous to 'virtual' in C++, not static.
If I leave out the method completely, then this is not what I know as
'Inheritance' anymore.
Shape is supposed to be an abstract base class, which -declares- (not
necessarily -defines-) a common interface for its subtypes. The code I
posted may not reflect this too well, it's just samplecode.
I doubt -any- dynamic binding will happen when completely leaving out
Shape's Draw method.
And btw.: What does dispatch mean? :) Is that the Ada term for dynamic
binding?
- Matthias
next prev parent reply other threads:[~2004-10-12 8:01 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-11 16:01 Classwide Parameter? matthias_k
2004-10-11 16:53 ` Matthew Heaney
2004-10-11 17:08 ` matthias_k
2004-10-11 19:16 ` Simon Wright
2004-10-11 22:53 ` Brian May
2004-10-12 2:29 ` Matthew Heaney
2004-10-12 8:01 ` matthias_k [this message]
2004-10-12 8:53 ` Martin Krischik
2004-10-12 13:10 ` Matthew Heaney
2004-10-12 7:59 ` Dmitry A. Kazakov
[not found] ` <ckg3h6$qau$03$1@news.t-online.com>
2004-10-12 8:14 ` matthias_k
2004-10-12 15:13 ` Dmitry A. Kazakov
2004-10-12 8:10 ` Martin Krischik
replies disabled
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox