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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: discriminant questions
Date: Mon, 19 Sep 2011 09:39:15 +0200
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Date: 2011-09-19T09:39:15+02:00
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On Sun, 18 Sep 2011 12:20:26 -0700 (PDT), Maciej Sobczak wrote:

> On Sep 18, 8:01�pm, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
> wrote:
> 
>> I don't care about iterators and accessors, they IMO are just
>> misconceptions coming from languages with pointers.
> 
> Problem: enumerate elements from two parallel containers (aka
> zipping).

What is wrong with using relative positions? Actually, mathematically,
there is no other way, and the word enumeration technically means a mapping
of the elements of a set onto a set numbers.

> Which might mean that the concept of pointers is not completely
> missing the point (pun intended).

It does. Consider a container located in a machine registers, where are the
pointers? The pointer itself is based on an enumeration in mathematical
sense of this word, where memory elements are mapped onto numbers.

The problem of pointers/iterators etc is that they require more than needed
(persistent element identity), which is a burden for both the container
designer and the user of. It might be a minor problem for C++, which walked
wrong path from very beginning: in C you can have pointer to almost
anything. But Ada tried not fall into this.

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