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From: Georg Bauhaus <bauhaus@futureapps.invalid>
Newsgroups: comp.lang.ada
Subject: Re: Design of cross referring types/classes and proper usage of
 containers
Date: Thu, 6 Aug 2015 07:00:24 +0000 (UTC)
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Date: 2015-08-06T07:00:24+00:00
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"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote:
> On Wed, 5 Aug 2015 10:51:36 -0700 (PDT), Serge Robyns wrote:
> 
>> Limited objects is one of these things I'm struggling getting my head
>> around.  I will need to (re)read about it to fully understand their
>> purpose as for now I perceive them as a pain.
> 
> Limited object is an object with an identity (inside its value). That is
> why you cannot copy it. It is neither a pain or bliss, just an aspect of
> design. Some things have identity some don't, you choose the type
> appropriately.

Invariable identity may be more suggestive.
Like Earth and Mars: you may change them,
but cannot change Mars to be like Earth
and then have it take Earth's place. That is,
Mars stays Mars no matter how you'd change it.