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=-0.3 required=5.0 tests=BAYES_00,
	REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4
X-Google-Thread: 103376,100eb0a59892e906
X-Google-Attributes: gid103376,domainid0,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news1.google.com!news2.google.com!npeer01.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!cyclone1.gnilink.net!gnilink.net!nx02.iad.newshosting.com!newshosting.com!newsfeed.icl.net!newsfeed.fjserv.net!newsfeed00.sul.t-online.de!newsfeed01.sul.t-online.de!t-online.de!newsfeed.arcor.de!newsspool4.arcor-online.net!news.arcor.de.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: How to pass around access types to interfaces?
Newsgroups: comp.lang.ada
User-Agent: 40tude_Dialog/2.0.15.1
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Reply-To: mailbox@dmitry-kazakov.de
Organization: cbb software GmbH
References: 
 <c5772601-5fc5-4f2c-a75d-241accf9072d@k30g2000hse.googlegroups.com>
 <op.ujk7aodyz25lew@macpro.krischik.com>
 <wccej24uxsi.fsf@shell01.TheWorld.com>
Date: Sun, 26 Oct 2008 09:02:51 +0100
Message-ID: <il41wscr7m2r.1ud5r5ac3loby.dlg@40tude.net>
NNTP-Posting-Date: 26 Oct 2008 09:02:51 CET
NNTP-Posting-Host: 83332527.newsspool2.arcor-online.net
X-Trace: 
 DXC=m`?9EmQReaj9kIfcjg:0fdA9EHlD;3Ycb4Fo<]lROoRa4nDHegD_]Rej0Cc=GPDG2dDNcfSJ;bb[eIRnRBaCd<Mn;QiHab@A2<eR:kZ<?gO\Go
X-Complaints-To: usenet-abuse@arcor.de
Xref: g2news1.google.com comp.lang.ada:2499
Date: 2008-10-26T09:02:51+01:00
List-Id: <comp.lang.ada>

On Sat, 25 Oct 2008 18:15:09 -0400, Robert A Duff wrote:

> "Martin Krischik" <krischik@users.sourceforge.net> writes:
> 
>> Am 24.10.2008, 13:45 Uhr, schrieb Sven <sven.weidauer@gmail.com>:
>>
>>>   type My_Interface_Access is access all My_Interface'Class;
>>
>> Do you realy need an access type? Read:
>>
>> http://en.wikibooks.org/wiki/Ada_Programming/Object_Orientation#The_class-wide_type
>>
>> If so, does it need to be an access all? Read:
> 
> In my experience, access-to-class-wide types almost always need to have
> "all", because you often want to convert from access-to-T2 up to
> access-to-T1'Class (where T2 is a descendant of T1).

It would be nice if that were finally fixed! [*]

But, in general it is better to use only access to class-wide. So the cases
where access to T2 is converted to access to T1 are suspicious to me. When
that happens I readily use Unchecked_Conversion, since it is already
broken.

--------
*  Similar issue: there is no good way to obtain a pool-specific access
type from Finalize.

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