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From: george.priv@gmail.com
Newsgroups: comp.lang.ada
Subject: Re: How to return an empty aggregate
Date: Sat, 5 Apr 2008 09:04:29 -0700 (PDT)
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Date: 2008-04-05T09:04:29-07:00
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On Apr 5, 9:48 am, Maciej Sobczak <see.my.homep...@gmail.com> wrote:
> On 5 Kwi, 01:58, george.p...@gmail.com wrote:
>
> > To me it seems that simple callback will be much more simple and clear
> > way to achieve the same result.
>
> It depends where you start with the design. If you start with
> stateless concrete factories (or you just see the whole picture right
> from the beginning), then callbacks will seem attractive. But if you
> start from the user site without knowing up-front what will kind of
> factory will be used then 'Class is the OO way to solve the problem.
>
> What will you do with the callback interface if at some point you
> discover that stateful factory will be most appropriate? Will you mess
> around with local functions that manipulate state from their enclosing
> scope? What about many such factories that have distinct states? And
> so on.
>
> > > If it's stateless, then it does not need any protection - there is
> > > nothing to protect.
>
> > except for reenterance that in most of cases matter for that type of
> > objects.
>
> If it's stateless, then reentrance is given for free.
>
> --
> Maciej Sobczak *www.msobczak.com*www.inspirel.com

Can you provide non-academic example?