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From: "Robert I. Eachus" <rieachus@comcast.net>
Subject: Re: Usage of Interfaces with Ada 95
Date: Tue, 30 Sep 2003 03:11:02 GMT
Date: 2003-09-30T03:11:02+00:00	[thread overview]
Message-ID: <3F78F430.1070909@comcast.net> (raw)
In-Reply-To: RgNdb.7920$kD3.7890@nwrdny03.gnilink.net

Hyman Rosen wrote:

> Me too. How unfortunate that in Ada, to get abilities similar
> to C++'s constructors, destructors, and assignment operator
> you must inherit from a common base class!

Nope!  Mix-ins to the rescue.  You can mix a component of a type derived 
from Controlled (or Limited Controlled) into an uncontrolled type.  In 
fact, the base type doesn't even need to be tagged.  Access 
discriminants can be used to allow the operations of the controlled 
component to access the entire record.  (But if you use this style you 
will find that the access discriminants are not often needed.)

-- 
                                                     Robert I. Eachus

"Quality is the Buddha. Quality is scientific reality. Quality is the 
goal of Art. It remains to work these concepts into a practical, 
down-to-earth context, and for this there is nothing more practical or 
down-to-earth than what I have been talking about all along...the repair 
of an old motorcycle."  -- from Zen and the Art of Motorcycle 
Maintenance by Robert Pirsig




  reply	other threads:[~2003-09-30  3:11 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-09-26 16:36 Usage of Interfaces with Ada 95 Michael Erdmann
2003-09-26 16:50 ` chris
2003-09-26 16:55 ` Hyman Rosen
2003-09-26 19:10   ` Michael Erdmann
2003-09-26 20:37     ` Hyman Rosen
2003-09-27 15:05       ` Michael Erdmann
2003-09-28  2:11         ` Matthew Heaney
2003-09-29  2:25         ` George Shapovalov
2003-09-28  2:14   ` Matthew Heaney
2003-09-28  8:28     ` Michael Erdmann
2003-09-28 14:33       ` Matthew Heaney
2003-09-28 15:09         ` Michael Erdmann
2003-09-28 21:50           ` Matthew Heaney
2003-09-30  4:57             ` Michael Erdmann
2003-09-30 10:02               ` Mário Amado Alves
2003-09-30 12:31               ` Matthew Heaney
2003-09-30 19:58                 ` Michael Erdmann
2003-09-28 17:10         ` Simon Wright
2003-09-28 21:52           ` Matthew Heaney
2003-09-28 21:58           ` Matthew Heaney
2003-09-29 19:37             ` Georg Bauhaus
2003-09-29 19:45               ` Georg Bauhaus
2003-09-30  7:10               ` Preben Randhol
2003-09-29 20:11             ` Simon Wright
2003-09-29 22:56               ` Matthew Heaney
2003-09-30 14:53                 ` Matthew Heaney
2003-09-30 16:13                   ` Preben Randhol
2003-09-29 13:49           ` Matthew Heaney
2003-09-28 18:22       ` Robert I. Eachus
2003-09-29  3:02         ` Hyman Rosen
2003-09-30  3:11           ` Robert I. Eachus [this message]
2003-09-30 13:38             ` Hyman Rosen
2003-09-30 21:46               ` Robert I. Eachus
2003-09-30 22:10                 ` Hyman Rosen
2003-10-01  2:30                   ` Robert I. Eachus
2003-10-01  2:41                   ` Robert I. Eachus
2003-10-01 13:21                     ` Hyman Rosen
2003-10-01 17:01                       ` Robert I. Eachus
2003-10-01 18:46                       ` Matthew Heaney
2003-09-29 14:52       ` Stephen Leake
2003-09-29 23:00         ` Matthew Heaney
2003-09-30 12:49           ` Marin David Condic
2003-09-30 23:48             ` Matthew Heaney
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