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!feeder.eternal-september.org!nntp-feed.chiark.greenend.org.uk!ewrotcd!newsfeed.xs3.de!io.xs3.de!news.jacob-sparre.dk!franka.jacob-sparre.dk!pnx.dk!.POSTED.rrsoftware.com!not-for-mail
From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Strings with discriminated records
Date: Wed, 30 May 2018 15:11:23 -0500
Organization: JSA Research & Innovation
Message-ID: <pen0hn$2k6$1@franka.jacob-sparre.dk>
References: <55ce14eb-6b83-4ea0-a550-f9e1410d0b06@googlegroups.com>
 <704ab1a8-c954-460e-81e7-05c64fcfaba4@googlegroups.com>
 <c349a644-8453-4159-a38f-c41b1a209f16@googlegroups.com>
 <pedqs5$1oda$1@gioia.aioe.org>
 <71501ba6-766e-45df-927b-0ed908fba28e@googlegroups.com>
 <peegke$rt1$1@gioia.aioe.org> <pekkcn$i8d$1@franka.jacob-sparre.dk>
 <peljsm$q5i$1@gioia.aioe.org>
Injection-Date: Wed, 30 May 2018 20:11:35 -0000 (UTC)
Injection-Info: franka.jacob-sparre.dk;
 posting-host="rrsoftware.com:24.196.82.226";
	logging-data="2694"; mail-complaints-to="news@jacob-sparre.dk"
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2900.5931
X-RFC2646: Format=Flowed; Response
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.7246
Xref: reader02.eternal-september.org comp.lang.ada:52794
Date: 2018-05-30T15:11:23-05:00
List-Id: <comp.lang.ada>

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
news:peljsm$q5i$1@gioia.aioe.org...
> On 2018-05-30 12:31 AM, Randy Brukardt wrote:
>> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
>> news:peegke$rt1$1@gioia.aioe.org...
>> ...
>>> as a poor-man solution to supertyping. I.e. if it were possible to make
>>> Message a subtype of String (by providing conversions), you could simply
>>> write:
>>>
>>>     M : Message := "Hello World";
>>
>> Or you could just give string literals to type Message (although you'll 
>> have
>> to wait a bit for that capability -- but it should be in Ada 2020 -
>> finally).
>
> Yes, I heard about use-defined literals, I am glad they made into Ada.
>
> However subtyping per conversions is a more general approach which would 
> work for literals too as it does with universal types.

Yes, but it's never gotten any traction. I've never been able to get any 
interest in any sort of user-defined conversion - there is a large faction 
that thinks function calls are good enough for that.

                              Randy.