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From: Thomas <fantome.forums.tDeContes@free.fr.invalid>
Subject: Re: Ada and Unicode
Date: Sun, 03 Apr 2022 19:24:11 +0200	[thread overview]
Message-ID: <fantome.forums.tDeContes-6263C7.19241103042022@news.free.fr> (raw)
In-Reply-To: s5k0ne$opv$1@gioia.aioe.org

In article <s5k0ne$opv$1@gioia.aioe.org>,
 "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote:

> On 2021-04-19 15:15, Luke A. Guest wrote:
> > On 19/04/2021 14:10, Dmitry A. Kazakov wrote:
> > 
> >>> They're different types and should be incompatible, because, well, 
> >> they are. What does Ada have that allows for this that other languages 
> >> doesn't? Oh yeah! Types!
> >>
> >> They are subtypes, differently constrained, like Positive and Integer. 
> > 
> > No they're not. They're subtypes only and therefore compatible. The UTF 
> > string isn't constrained in any other ways.
> 
> Of course it is. There could be string encodings that have no Unicode 
> counterparts and thus missing in UTF-8/16.

1
there is missing a validity function to tell weather a given 
UTF_8_String is valid or not,
and a Dynamic_Predicate on the subtype UTF_8_String connected to the 
function.

2
more important, (when non-ASCII,) valid UTF_8_String *do not* represent 
the same thing as themselves converted to String.

> 
> >> Operations are same values are differently constrained. It does not 
> >> make sense to consider ASCII 'a', Latin-1 'a', UTF-8 'a' different. It 
> >> is same glyph differently encoded. Encoding is a representation 
> >> aspect, ergo out of the interface!

it works because 'a' is ASCII.
if you try it with a non-ASCII character, all goes wrong.

-- 
RAPID maintainer
http://savannah.nongnu.org/projects/rapid/

  reply	other threads:[~2022-04-03 17:24 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-17 22:03 Ada and Unicode DrPi
2021-04-18  0:02 ` Luke A. Guest
2021-04-19  9:09   ` DrPi
2021-04-19  8:29 ` Maxim Reznik
2021-04-19  9:28   ` DrPi
2021-04-19 13:50     ` Maxim Reznik
2021-04-19 15:51       ` DrPi
2021-04-19 11:15   ` Simon Wright
2021-04-19 11:50     ` Luke A. Guest
2021-04-19 15:53     ` DrPi
2022-04-03 19:20     ` Thomas
2022-04-04  6:10       ` Vadim Godunko
2022-04-04 14:19         ` Simon Wright
2022-04-04 15:11           ` Simon Wright
2022-04-05  7:59           ` Vadim Godunko
2022-04-08  9:01             ` Simon Wright
2023-03-30 23:35         ` Thomas
2022-04-04 14:33       ` Simon Wright
2021-04-19  9:08 ` Stephen Leake
2021-04-19  9:34   ` Dmitry A. Kazakov
2021-04-19 11:56   ` Luke A. Guest
2021-04-19 12:13     ` Luke A. Guest
2021-04-19 15:48       ` DrPi
2021-04-19 12:52     ` Dmitry A. Kazakov
2021-04-19 13:00       ` Luke A. Guest
2021-04-19 13:10         ` Dmitry A. Kazakov
2021-04-19 13:15           ` Luke A. Guest
2021-04-19 13:31             ` Dmitry A. Kazakov
2022-04-03 17:24               ` Thomas [this message]
2021-04-19 13:24         ` J-P. Rosen
2021-04-20 19:13           ` Randy Brukardt
2022-04-03 18:04           ` Thomas
2022-04-06 18:57             ` J-P. Rosen
2022-04-07  1:30               ` Randy Brukardt
2022-04-08  8:56                 ` Simon Wright
2022-04-08  9:26                   ` Dmitry A. Kazakov
2022-04-08 19:19                     ` Simon Wright
2022-04-08 19:45                       ` Dmitry A. Kazakov
2022-04-09  4:05                         ` Randy Brukardt
2022-04-09  7:43                           ` Simon Wright
2022-04-09 10:27                           ` DrPi
2022-04-09 16:46                             ` Dennis Lee Bieber
2022-04-09 18:59                               ` DrPi
2022-04-10  5:58                             ` Vadim Godunko
2022-04-10 18:59                               ` DrPi
2022-04-12  6:13                               ` Randy Brukardt
2021-04-19 16:07         ` DrPi
2021-04-20 19:06         ` Randy Brukardt
2022-04-03 18:37           ` Thomas
2022-04-04 23:52             ` Randy Brukardt
2023-03-31  3:06               ` Thomas
2023-04-01 10:18                 ` Randy Brukardt
2021-04-19 16:14   ` DrPi
2021-04-19 17:12     ` Björn Lundin
2021-04-19 19:44       ` DrPi
2022-04-16  2:32   ` Thomas
2021-04-19 13:18 ` Vadim Godunko
2022-04-03 16:51   ` Thomas
2023-04-04  0:02     ` Thomas
2021-04-19 22:40 ` Shark8
2021-04-20 15:05   ` Simon Wright
2021-04-20 19:17     ` Randy Brukardt
2021-04-20 20:04       ` Simon Wright
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