From: matthias_k <nospam@digitalraid.com>
Subject: Re: Classwide Parameter?
Date: Mon, 11 Oct 2004 19:08:24 +0200
Date: 2004-10-11T19:08:24+02:00 [thread overview]
Message-ID: <ckeelg$dkb$05$1@news.t-online.com> (raw)
In-Reply-To: <uvfdhozbl.fsf@earthlink.net>
Thanks for that answer. However, I'm still having problems (I have
rewritten the code to be in one single package now):
<snip>
package Graphics is
type Shape is abstract tagged null record;
procedure Draw (Obj: Shape'Class);
type Circle is new Shape with record
Radius: Float;
Center: Float;
end record;
procedure Draw (Obj: Circle);
type Square is new Shape with record
Size: Float;
end record;
procedure Draw (Obj: Square);
end;
</snip>
Now, what I want is to have different implementations of the Draw method
for each Subtype. However, if I run this program:
<snip>
with Graphics;
use Graphics;
procedure Demo is
type Reference is access all Shape'Class;
Object: Reference;
begin
Object := new Circle;
Draw( Object.all );
Object := new Square;
Draw( Object.all );
end;
</snip>
The Shape's Draw method is always called here but it shouldn't. No late
binding happens. I have tried to make it abstract, but it didn't even
compile then. What's wrong?
- Matthias
next prev parent reply other threads:[~2004-10-11 17:08 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-10-11 16:01 Classwide Parameter? matthias_k
2004-10-11 16:53 ` Matthew Heaney
2004-10-11 17:08 ` matthias_k [this message]
2004-10-11 19:16 ` Simon Wright
2004-10-11 22:53 ` Brian May
2004-10-12 2:29 ` Matthew Heaney
2004-10-12 8:01 ` matthias_k
2004-10-12 8:53 ` Martin Krischik
2004-10-12 13:10 ` Matthew Heaney
2004-10-12 7:59 ` Dmitry A. Kazakov
[not found] ` <ckg3h6$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