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From: Maciej Sobczak <see.my.homepage@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Limited use for limited with?
Date: Wed, 29 Sep 2010 01:25:29 -0700 (PDT)
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On 29 Wrz, 08:03, Ludovic Brenta <ludo...@ludovic-brenta.org> wrote:

> > Consider:
>
> > =A0 =A0procedure Register (X : in Object'Class);
>
> > X will be passed by reference, but there is still nothing in the
> > signature (apart from the name of the operation) that would suggest
> > that the reference will be leaked out of the operation's scope. So the
> > user does this:
>
> > declare
> > =A0 =A0X : My_Concrete_Object;
> > begin
> > =A0 =A0Register (X);
> > endl;
>
> > and bang, everything breaks into pieces.
>
> No, because this is Ada :)
[...]

I was thinking about Register storing the access value somewhere, not
copying the whole object.

The whole idea of registering something is that state changes that are
provoked by the registry are visible to the original creator of the
object. Copying X by value makes no sense in this scenario, because
object updates would not affect the original object. I want to
logically register *my* object, not its copy.

And of course there is still the possibility of Object to be limited
(which is actually the case) - then no deep copy is possible.

--
Maciej Sobczak * http://www.inspirel.com