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=-2.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,
	MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no
	version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,309015504ed37ff0
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-09-30 02:55:08 PST
Path: 
 archiver1.google.com!news2.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!newsfeed.stueberl.de!teaser.fr!enst.fr!melchior!cuivre.fr.eu.org!melchior.frmug.org!not-for-mail
From: =?iso-8859-1?Q?M=E1rio_Amado_Alves?= <amado.alves@netcabo.pt>
Newsgroups: comp.lang.ada
Subject: RE: Usage of Interfaces with Ada 95
Date: Tue, 30 Sep 2003 11:02:04 +0100
Organization: Cuivre, Argent, Or
Message-ID: <mailman.13.1064915564.25614.comp.lang.ada@ada-france.org>
NNTP-Posting-Host: lovelace.ada-france.org
Mime-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
X-Trace: melchior.cuivre.fr.eu.org 1064915565 863 80.67.180.195 (30 Sep 2003
 09:52:45 GMT)
X-Complaints-To: usenet@melchior.cuivre.fr.eu.org
NNTP-Posting-Date: Tue, 30 Sep 2003 09:52:45 +0000 (UTC)
To: <comp.lang.ada@ada-france.org>
Return-Path: <amado.alves@netcabo.pt>
X-Priority: 3 (Normal)
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook, Build 10.0.2627
Importance: Normal
In-Reply-To: <l2fn41-0j8.ln1@boavista.snafu.de>
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2727.1300
X-OriginalArrivalTime: 30 Sep 2003 09:47:35.0484 (UTC)
	FILETIME=[E06F2FC0:01C38737]
X-Virus-Scanned: by amavisd-new-20030616-p5 (Debian) at ada-france.org
X-BeenThere: comp.lang.ada@ada-france.org
X-Mailman-Version: 2.1.2
Precedence: list
List-Id: Gateway to the comp.lang.ada Usenet newsgroup
	<comp.lang.ada.ada-france.org>
List-Unsubscribe: <http://www.ada-france.org/mailman/listinfo/comp.lang.ada>,
	<mailto:comp.lang.ada-request@ada-france.org?subject=unsubscribe>
List-Post: <mailto:comp.lang.ada@ada-france.org>
List-Help: <mailto:comp.lang.ada-request@ada-france.org?subject=help>
List-Subscribe: <http://www.ada-france.org/mailman/listinfo/comp.lang.ada>,
	<mailto:comp.lang.ada-request@ada-france.org?subject=subscribe>
Xref: archiver1.google.com comp.lang.ada:3
Date: 2003-09-30T11:02:04+01:00

> >   generic
> >      type Iterator_Type is private;
> >      with function Succ (Iterator : Iterator_Type)
> >        return Iterator_Type is <>;
> >      with procedure Process (Iterator : Iterator_Type) is <>;
> >      with function "=" (L, R : Iterator_Type)
> >        return Boolean is <>;
> >   procedure Generic_Algorithm (First, Back : Iterator_Type);
>
> I think the is a different view on the topic by defining a 
> functionality of an interface, providing a generic 
> implementation which defines the 
> interface for the programmer. This was exactly what i dont like to 
> do. I dont like to spent the effort of breaking down a concept into 
> a generic implementation. This is the reason why i like to 
> use interfaces.

Somebody has to implement at some point. I think the example come short.
There is a 'zero-implementation' way to specify interfaces in Ada:
signature packages. The signature package for the stuff above is

generic
  type Iterator_Type is private;
  with function Succ (Iterator : Iterator_Type) return Iterator_Type is
<>;
  with procedure Process (Iterator : Iterator_Type) is <>;
  with function "=" (L, R : Iterator_Type) return Boolean is <>;
  with procedure Generic_Algorithm (First, Back : Iterator_Type) is <>;
package Signature is end;