comp.lang.ada
 help / color / mirror / Atom feed
From: "Randy Brukardt" <randy@rrsoftware.com>
Subject: Re: Custom Storage Pool questions
Date: Mon, 20 Sep 2021 18:48:02 -0500	[thread overview]
Message-ID: <sib6jj$mij$1@franka.jacob-sparre.dk> (raw)
In-Reply-To: shpf4d$1a6s$1@gioia.aioe.org

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:shpf4d$1a6s$1@gioia.aioe.org...
> On 2021-09-14 02:48, Jere wrote:
...
> The problem with unconstrained arrays is not that the bounds are not 
> allocated, they are, but the semantics of X'Address when applied to 
> arrays.
>
> A'Address is the address of the first array element, not of the array 
> object. For a pool designer it constitutes a problem of getting the array 
> object by address. This is what Emmanuel discusses in the blog.

Right, this is why Janus/Ada never "fixed" 'Address to follow the Ada 
requirement. (Our Ada 83 compiler treats the "object" as whatever the 
top-level piece is, for an unconstrained array, that's the bounds -- the 
data lies elsewhere and is separately allocated -- something that follows 
from slice semantics.)

I suppose your suggestion of implementing yet-another-attribute is probably 
the right way to go, and then finding every use of 'Address in existing RRS 
Janus/Ada code and changing it to use the new attribute that works "right".

                                               Randy.



> [ The motivation behind Ada choice was probably to keep the semantics 
> implementation-independent. ]
>
> Consider for example a list of String elements. When Allocate is called 
> with String, it returns the address of all String. But that is not the 
> address you would get if you applied 'Address. You have to add/subtract 
> some offset in order to get one from another.
>
> In Simple Components this offset is determined at run-time for each 
> generic instance.
>
> Of course, a proper solution would be fixing Ada by adding another address 
> attribute:
>
>    X'Object_Address
>
> returning the first address of the object as allocated.
>
> -- 
> Regards,
> Dmitry A. Kazakov
> http://www.dmitry-kazakov.de 


  parent reply	other threads:[~2021-09-20 23:48 UTC|newest]

Thread overview: 97+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-13  0:53 Custom Storage Pool questions Jere
2021-09-13  5:29 ` Randy Brukardt
2021-09-14  1:04   ` Jere
2021-09-21  0:06     ` Randy Brukardt
2021-09-18 11:32   ` Simon Wright
2021-09-20  0:31   ` Jere
2021-09-20  6:34     ` Niklas Holsti
2021-09-20  6:48       ` Emmanuel Briot
2021-09-20  7:35         ` Dmitry A. Kazakov
2021-09-20 16:59         ` Shark8
2021-09-21  0:50         ` Randy Brukardt
2021-09-21 23:08           ` Jere
2021-09-28  4:42             ` Randy Brukardt
2021-10-02 23:19               ` Jere
2021-10-03  8:52                 ` Dmitry A. Kazakov
2021-10-14  1:26                   ` Randy Brukardt
2021-09-13 11:12 ` J-P. Rosen
2021-09-14  0:48   ` Jere
2021-09-14  6:08     ` J-P. Rosen
2021-09-15  0:39       ` Jere
2021-09-15  7:01         ` Simon Wright
2021-09-16 23:32           ` Jere
2021-09-20 23:51             ` Randy Brukardt
2021-09-21 22:40               ` Jere
2021-09-14  6:23     ` Dmitry A. Kazakov
2021-09-14  6:42       ` J-P. Rosen
2021-09-14  7:00         ` Dmitry A. Kazakov
2021-09-20 23:58         ` Randy Brukardt
2021-09-15  0:21       ` Jere
2021-09-15  6:54         ` Dmitry A. Kazakov
2021-09-20 23:48       ` Randy Brukardt [this message]
2021-09-14 10:54     ` Egil H H
2021-09-15  0:11       ` Jere
2021-09-15 16:43 ` Simon Wright
2021-09-15 17:03   ` Simon Wright
2021-09-15 19:07   ` Dmitry A. Kazakov
2021-09-15 20:40     ` Simon Wright
2021-09-16  7:12       ` Emmanuel Briot
2021-09-16 23:21         ` Jere
2021-09-17  7:08           ` Emmanuel Briot
2021-09-17  7:18           ` Simon Wright
2021-09-17 13:56           ` Dmitry A. Kazakov
2021-09-17 19:46             ` Simon Wright
2021-09-17 20:39               ` Dmitry A. Kazakov
2021-09-17 21:17                 ` Niklas Holsti
2021-09-18  7:49                   ` Dmitry A. Kazakov
2021-09-18  9:03                     ` Niklas Holsti
2021-09-18 10:22                       ` Dmitry A. Kazakov
2021-09-18 15:59                         ` Niklas Holsti
2021-09-18 16:19                           ` Dmitry A. Kazakov
2021-09-19 10:36                             ` Niklas Holsti
2021-09-19 11:41                               ` Dmitry A. Kazakov
2021-09-20  7:05                                 ` Niklas Holsti
2021-09-20  7:35                                   ` Dmitry A. Kazakov
2021-09-20  8:08                                     ` Niklas Holsti
2021-09-20  8:28                                       ` Dmitry A. Kazakov
2021-09-21  0:45                                         ` Randy Brukardt
2021-09-21  0:40                                       ` Randy Brukardt
2021-09-21  0:30                                 ` Randy Brukardt
2021-09-21  0:37                                 ` Randy Brukardt
2021-09-21  6:28                                   ` Dmitry A. Kazakov
2021-09-28  4:38                                     ` Randy Brukardt
2021-09-28  7:00                                       ` Dmitry A. Kazakov
2021-09-21  0:26                         ` Randy Brukardt
2021-09-21  6:51                           ` Dmitry A. Kazakov
2021-09-28  4:31                             ` Randy Brukardt
2021-09-28  6:56                               ` Dmitry A. Kazakov
2021-09-28  7:52                                 ` Simon Wright
2021-09-28  8:07                                   ` Dmitry A. Kazakov
2021-09-28 22:04                                     ` Randy Brukardt
2021-09-29  7:57                                       ` Dmitry A. Kazakov
2021-09-29 14:41                                         ` Shark8
2021-09-29 15:16                                           ` Dmitry A. Kazakov
2021-09-30  0:16                                             ` Randy Brukardt
2021-09-30  8:08                                               ` Dmitry A. Kazakov
2021-10-01  0:04                                                 ` Randy Brukardt
2021-10-01  8:25                                                   ` Dmitry A. Kazakov
2021-10-02  9:06                                                     ` Randy Brukardt
2021-10-02 10:18                                                       ` Dmitry A. Kazakov
2021-10-03  4:33                                                         ` Randy Brukardt
2021-10-03  8:40                                                           ` Dmitry A. Kazakov
2021-10-14  1:21                                                             ` Randy Brukardt
2021-10-14  3:12                                                               ` philip...@gmail.com
2021-10-14  7:31                                                               ` Dmitry A. Kazakov
2021-10-15  0:36                                                                 ` Randy Brukardt
2021-10-15  8:08                                                                   ` Stephen Leake
2021-10-15  8:18                                                                     ` Dmitry A. Kazakov
2021-10-15 22:22                                                                     ` Randy Brukardt
2021-10-15  8:15                                                                   ` Dmitry A. Kazakov
2021-10-15 22:44                                                                     ` Randy Brukardt
2021-10-16  9:00                                                                       ` Dmitry A. Kazakov
2021-10-16 14:32                                                                         ` Simon Wright
2021-10-16 15:06                                                                           ` Dmitry A. Kazakov
2021-10-18 14:23                                                                             ` Shark8
2021-09-21  0:19                     ` Randy Brukardt
2021-09-21  0:18                 ` Randy Brukardt
2021-09-16  8:41       ` Dmitry A. Kazakov
replies disabled

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox