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: 103376,887e603b44eb2706
X-Google-Attributes: gid103376,public
X-Google-Language: ENGLISH,ASCII-7-bit
Path: 
 g2news2.google.com!news4.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!newsfeed00.sul.t-online.de!newsfeed01.sul.t-online.de!t-online.de!newsfeed.arcor.de!newsspool1.arcor-online.net!news.arcor.de.POSTED!not-for-mail
From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: null exclusion and generics
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: <1161262319.24061.19.camel@localhost.localdomain>
 <reSdnSjHmLyTRqrYnZ2dnUVZ_qadnZ2d@megapath.net>
Date: Fri, 20 Oct 2006 09:57:41 +0200
Message-ID: <rzi6fg9dvwkj$.1sgq0u8z632e4.dlg@40tude.net>
NNTP-Posting-Date: 20 Oct 2006 09:57:41 CEST
NNTP-Posting-Host: 292d3df7.newsspool4.arcor-online.net
X-Trace: 
 DXC==ZICjlE<P2B74okIm;?DS@4IUK<Cl32<A4Fo<]lROoRA4nDHegD_]REEDZ^>WT\7JIDNcfSJ;bb[EFCTGGVUmh?DN\HXHJ4e80NCS\DDa:9ngE
X-Complaints-To: usenet-abuse@arcor.de
Xref: g2news2.google.com comp.lang.ada:7063
Date: 2006-10-20T09:57:41+02:00
List-Id: <comp.lang.ada>

On Thu, 19 Oct 2006 15:08:17 -0500, Randy Brukardt wrote:

> So all access types are initialized with null, and if the subtype is
> null-excluding, that will automatically raise Constraint_Error. A null
> exclusion is essentially a kind of constraint (it is not technically a
> constraint, but that has to do with independence from other forms of
> constraint). Think of  it being like:
> 
>     subtype A is Integer range 1 .. 10;
> 
>     Obj : A := Integer'First;
> 
> which also will raise C_E. (If we had allowed a way to declare automatic
> initializations for scalar types -- something I wish we had done -- it would
> have had a similar effect as the explicit initialization here).

This is one more reason to finally introduce a sane
construction/destruction model in Ada. Compromises never buy off.

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