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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Convention for naming of packages
Date: Tue, 14 Feb 2012 16:26:31 +0100
Organization: cbb software GmbH
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Date: 2012-02-14T16:26:31+01:00
List-Id: <comp.lang.ada>

On Tue, 14 Feb 2012 15:40:03 +0100, Yannick Duch�ne (Hibou57) wrote:

> Le Tue, 14 Feb 2012 14:33:43 +0100, Dmitry A. Kazakov  
> <mailbox@dmitry-kazakov.de> a �crit:
>> You shall never provide a constructing function (=factory) for singleton
>> types.
> It's initialized at package elaboration. A function can still be used to  
> return the kind of reference to the singleton.

But that is either not a constructing function or else not a singleton.

The former is because such a function would not return the target type.

The latter is if you consider access type as a stand-alone object. In that
case there could be more than one pointer objects, because you provided a
way to create them by giving a factory that returns a pointer.

> Lazy initialization may  
> also be used, while always under controle of package elaboration, which  
> will be the only one to set the initial value of the Inialized flag to  
> False.

You shall not expose this implementation detail in the interface.

> That said, I have a strange feeling I missed what you wanted to point. Did  
> I?

No a point, just an almost tautological statement: singleton shall have no
factory.

> (yes, I finally must have missed something)

Once you sorted out references from objects, public from private,
constructors from factory functions...

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de