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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: New aggregates with Ada 2022.
Date: Tue, 28 Jun 2022 09:52:11 +0200	[thread overview]
Message-ID: <t9ebvc$1amt$1@gioia.aioe.org> (raw)
In-Reply-To: t9d7u5$ogle$1@dont-email.me

On 2022-06-27 23:37, Randy Brukardt wrote:

> The distributed overhead that they cause is
> immense (for instance, you can't have a discontigious array represesentation
> with slices, unless you are willing to pay a substantial cost for *every*
> array parameter). They're the anti-abstraction feature.

There is nothing wrong with having non-contiguous slices of 
non-contiguous arrays! Contiguity of index does not automatically imply 
contiguity of element allocation, unless specifically required by the 
[sub]type constraint.

1D array abstraction is a mapping index -> element where

1. Index has an order. Index has operations 'Succ and 'Pred;

2. The mapping is convex. If there are elements for two indices, then 
there are elements for all indices between them.

Contiguity is a representation constraint.

One should be able to have an array equivalent of unbounded string with 
unbounded slices both allocated non-contiguously. The slices you could 
shrink or expand:

    Text (45..80) := "";  -- Cut a piece off

At the same time one should have a contiguous subtype of the same 
unbounded string for interfacing purposes, dealt by copy-out copy-in.

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

  parent reply	other threads:[~2022-06-28  7:52 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-19  7:59 New aggregates with Ada 2022 Blady
2022-06-19 14:15 ` Simon Wright
2022-06-20 19:36   ` Blady
2022-06-20 22:01     ` Simon Wright
2022-06-20 21:47 ` Randy Brukardt
2022-06-20 22:18   ` Dmitry A. Kazakov
2022-06-21 23:28     ` Randy Brukardt
2022-06-22  9:04       ` Dmitry A. Kazakov
2022-06-23  1:06         ` Randy Brukardt
2022-06-23  9:32           ` Dmitry A. Kazakov
2022-06-23 10:53             ` G.B.
2022-06-24  1:21               ` Randy Brukardt
2022-06-24  1:24             ` Randy Brukardt
2022-06-24  6:50               ` Dmitry A. Kazakov
2022-06-25  3:13                 ` Randy Brukardt
2022-06-25  8:50                   ` Dmitry A. Kazakov
2022-06-27 21:37                     ` Randy Brukardt
2022-06-28  5:36                       ` Niklas Holsti
2022-06-29  4:01                         ` Randy Brukardt
2022-06-29  8:30                           ` Jeffrey R.Carter
2022-06-29  9:04                             ` Dmitry A. Kazakov
2022-06-30  5:03                               ` Randy Brukardt
2022-06-30  8:44                                 ` Dmitry A. Kazakov
2022-06-29 11:06                             ` Niklas Holsti
2022-06-29 12:53                               ` Jeffrey R.Carter
2022-06-30  5:07                                 ` Randy Brukardt
2022-06-30  5:14                               ` Randy Brukardt
2022-06-30  8:31                                 ` Marius Amado-Alves
2022-07-01  5:20                                   ` Randy Brukardt
2022-06-30 10:30                                 ` Jeffrey R.Carter
2022-06-30 15:48                                   ` Marius Amado-Alves
2022-06-30 16:39                                     ` Jeffrey R.Carter
2022-07-01  0:07                                       ` Marius Amado-Alves
2022-06-28  7:52                       ` Dmitry A. Kazakov [this message]
2022-06-29  4:07                         ` Randy Brukardt
2022-06-29  7:24                           ` Dmitry A. Kazakov
2022-06-30  5:00                             ` Randy Brukardt
2022-06-21 23:39     ` Randy Brukardt
2022-06-22  8:26       ` Dmitry A. Kazakov
2022-06-23  1:10         ` Randy Brukardt
2022-06-23  9:32           ` Dmitry A. Kazakov
2022-06-20 22:10 ` Jesper Quorning
2022-06-20 22:59   ` Jesper Quorning
2022-06-21 23:20     ` Randy Brukardt
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