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,dbcfe2b0a74da57e
X-Google-Attributes: gid103376,public,usenet
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news3.google.com!fu-berlin.de!newsfeed.arcor.de!newsspool2.arcor-online.net!news.arcor.de.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Inherited Methods and such
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: <1190321119.206313.65290@57g2000hsv.googlegroups.com>
 <egz670qwxgyj$.15oz5zin5794w$.dlg@40tude.net>
 <1190408526.100291.265040@50g2000hsm.googlegroups.com>
 <9ukf2wtqjs0q$.iuijmal4x56b$.dlg@40tude.net>
 <1190497995.498679.119190@19g2000hsx.googlegroups.com>
 <1mw3qju08q8uj.sgzht7ld9ydc$.dlg@40tude.net>
 <1190579805.451187.71140@d55g2000hsg.googlegroups.com>
 <1i8ksr774bjbj.vpmnx3c0i9qz.dlg@40tude.net>
 <1190646125.024072.310020@19g2000hsx.googlegroups.com>
 <1r9s9v6pcjifl.vp4ktk0unpd1.dlg@40tude.net>
 <1190753631.240548.101820@19g2000hsx.googlegroups.com>
 <wcck5qdpq92.fsf@shell01.TheWorld.com>
 <1190843408.713838.128690@g4g2000hsf.googlegroups.com>
 <wccps02fw9v.fsf@shell01.TheWorld.com> <wcchclefuge.fsf@shell01.TheWorld.com>
 <1191012272.457766.273330@57g2000hsv.googlegroups.com>
 <uuiy8hvdrhef$.8tiuhv6kgf8f$.dlg@40tude.net>
 <1191099160.227234.125330@r29g2000hsg.googlegroups.com>
Date: Sun, 30 Sep 2007 10:38:11 +0200
Message-ID: <18raoy77i431w.1diy3loydmq9h$.dlg@40tude.net>
NNTP-Posting-Date: 30 Sep 2007 10:38:12 CEST
NNTP-Posting-Host: 08a0d075.newsspool4.arcor-online.net
X-Trace: 
 DXC=WXX=l16WbW<kUFX=Y?aLP;4IUK<Cl32<14Fo<]lROoR1^YC2XCjHcb9JRX@UK[JGi=DNcfSJ;bb[5IRnRBaCd<M>7S]SUVZ];98lKCJC39a4=>
X-Complaints-To: usenet-abuse@arcor.de
Xref: g2news2.google.com comp.lang.ada:2234
Date: 2007-09-30T10:38:12+02:00
List-Id: <comp.lang.ada>

On Sat, 29 Sep 2007 13:52:40 -0700, Maciej Sobczak wrote:

> On 29 Wrz, 22:35, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
> wrote:
> 
>> 1. It breaks encapsulation as you should make the record nature of type
>> public.
> 
> Why it would make any difference?
> The type is tagged and this is known. If it's tagged, then it has the
> record nature - no way and no reason to hide it.

It is a language fault that there are types which cannot be
user-constructed. The problem is that if you tried to fix the language, for
example by allowing a task object being shut down when finalized, you would
make them all records. Is it LISP or Ada?

>> 2. The base type cannot enforce vital construction code, when records are
>> exposed.
> 
> I don't understand this part.

If the object is just a record I can assemble it in any available way. And
there are many of them. You will have a difficult design problem to ensure
that all these ways do call your construction code. For example: 

Uninitialized base:

   X : Base;
begin
   return (X with ...) do ... end record;

Worked-around base:

   return (X'(Xs_Base with Something) with ...) do ... end record;

>> 4. Dispatch upon construction completion and before destruction beginning
>> is still impossible.

> Why?

It goes this way:

  return (Base with Mine) do My-take end record;

But the [class-wide] code to execute should be placed after "end record," 
IFF there is no following derived type under construction. Only compiler
magic can help here.

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