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=ham
	autolearn_force=no version=3.4.4
X-Google-Thread: 103376,100eb0a59892e906
X-Google-Attributes: gid103376,domainid0,public,usenet
X-Google-Language: ENGLISH,UTF8
Path: 
 g2news2.google.com!news1.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!wns14feed!worldnet.att.net!164.128.36.58!news.ip-plus.net!newsfeed.ip-plus.net!news.post.ch!not-for-mail
From: Martin Krischik <krischik@users.sourceforge.net>
Newsgroups: comp.lang.ada
Subject: Re: How to pass around access types to interfaces?
Date: Wed, 29 Oct 2008 15:15:20 +0100
Organization: Swisscom IP+ (post doesn't reflect views of Swisscom)
Message-ID: <49086ff8$1@news.post.ch>
References: 
 <c5772601-5fc5-4f2c-a75d-241accf9072d@k30g2000hse.googlegroups.com>
 	<op.ujk7aodyz25lew@macpro.krischik.com>
 <wccej24uxsi.fsf@shell01.TheWorld.com>
 	<op.ujm2apryz25lew@macpro.krischik.com>
 <8bd7e8eb-b463-4dea-8b62-42b6486557f0@u65g2000hsc.googlegroups.com>
NNTP-Posting-Host: 194.41.146.1
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-Trace: atlas.ip-plus.net 1225289724 5832 194.41.146.1 (29 Oct 2008 14:15:24
 GMT)
X-Complaints-To: abuse@ip-plus.net
NNTP-Posting-Date: Wed, 29 Oct 2008 14:15:24 +0000 (UTC)
User-Agent: Thunderbird 2.0.0.17 (Windows/20080914)
In-Reply-To: 
 <8bd7e8eb-b463-4dea-8b62-42b6486557f0@u65g2000hsc.googlegroups.com>
X-Original-NNTP-Posting-Host: w03duo.pnet.ch
X-Original-Trace: 29 Oct 2008 15:15:20 +0200, w03duo.pnet.ch
Xref: g2news2.google.com comp.lang.ada:8252
Date: 2008-10-29T15:15:20+01:00
List-Id: <comp.lang.ada>

Maciej Sobczak schrieb:
> On 26 Paź, 16:50, "Martin Krischik" <krisc...@users.sourceforge.net>
> wrote:
> 
>> But then: access to class wide is the kind of  
>> access which a C++ convert will uses without realy needing them. I should  
>> know, I am a C++ convert who made precisely that mistake.
> 
> It might depend on what you did in C++ before converting. ;-)
> Since most of the code does not need pointers anyway, the frequent
> idiom is to pass objects by reference (likely to the base class),
> something like:
> 
> void foo(const SomeClass & object);

Not the function call is the problem - the creation and storage of
objects is.

For example: now are you going to fill a vector<base_class&> with
objects? And how do you delete those objects again? This is where C++ lags.

In Ada we have Ada.Container.Indefinite_Vector which can hold Base'Class
objects. (Remember that is was me who requested the inclusion of
Ada.Container.Indefinite_Vector into the standard. It was also me who
created BC.Indefinite_Containers)

> I think that in the above context what is *really* dangerous and
> difficult to clean up is the C background, not C++. Unfortunately the
> former one prevails.

Well I did C before C++ and Modula-2 before that and Pascal before that.

Martin

-- 
mailto://krischik@users.sourceforge.net
Ada programming at: http://ada.krischik.com