From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!aioe.org!.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Bug in Ada - Latin 1 is not a subset of UTF-8
Date: Tue, 18 Oct 2016 10:45:03 +0200
Organization: Aioe.org NNTP Server
Message-ID: <nu4nee$18le$1@gioia.aioe.org>
References: <86f0d2fe-d498-4bc4-bb9d-e34629c89bb4@googlegroups.com>
 <nu3mkc$agg$1@dont-email.me> <nu4jnj$11va$1@gioia.aioe.org>
 <nu4m5k$g7g$1@dont-email.me>
NNTP-Posting-Host: vZYCW951TbFitc4GdEwQJg.user.gioia.aioe.org
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
X-Complaints-To: abuse@aioe.org
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101
 Thunderbird/45.4.0
X-Notice: Filtered by postfilter v. 0.8.2
Xref: news.eternal-september.org comp.lang.ada:32112
Date: 2016-10-18T10:45:03+02:00
List-Id: <comp.lang.ada>

On 18/10/2016 10:23, G.B. wrote:
> On 18.10.16 09:41, Dmitry A. Kazakov wrote:
>> On 18/10/2016 01:25, G.B. wrote:
>>> On 17.10.16 22:18, Lucretia wrote:
>>
>>> According to ISO 10646, UTF stands for UCS Transformation
>>> Format. So, it's a format, suggesting a representation.
>>>
>>> On similar grounds, one could define a string subtype for
>>> other types of objects, for example
>>>
>>>   subtype Number_String is String;
>>
>> You are wrong.
>
> The constraints on either UTF_String or or Number_String are
> not expressible as simple Ada subtypes. They are given by
> description and normative reference, respectively.

In the case of UTF-8 it is not a constraint. "Ä" has different 
representations as Latin-1 and UTF-8 strings.

Numeric character is a constraint expressible in Ada:

    subtype Numeric is Character range '0'..'9';

Numeric string constraint is not expressible, but it still a constraint.

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