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,MAILING_LIST_MULTI
	autolearn=unavailable autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,f813b1b9c8de30d6,start
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2001-03-07 03:50:08 PST
Path: 
 supernews.google.com!sn-xit-03!supernews.com!logbridge.uoregon.edu!newsfeed2.news.nl.uu.net!sun4nl!fr.usenet-edu.net!usenet-edu.net!enst!enst.fr!not-for-mail
From: Mario Amado Alves <maa@di.fct.unl.pt>
Newsgroups: comp.lang.ada
Subject: Getting a one-touch option (was: Ada95 tutorials with sample code)
Date: Wed, 7 Mar 2001 11:50:21 +0000 (WET)
Organization: ENST, France
Sender: comp.lang.ada-admin@ada.eu.org
Message-ID: <mailman.983965508.309.comp.lang.ada@ada.eu.org>
Reply-To: comp.lang.ada@ada.eu.org
NNTP-Posting-Host: marvin.enst.fr
Mime-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
X-Trace: avanie.enst.fr 983965508 13280 137.194.161.2 (7 Mar 2001 11:45:08
 GMT)
X-Complaints-To: usenet@enst.fr
NNTP-Posting-Date: Wed, 7 Mar 2001 11:45:08 +0000 (UTC)
To: "'comp.lang.ada@ada.eu.org'" <comp.lang.ada@ada.eu.org>
Return-Path: <maa@di.fct.unl.pt>
X-Authentication-Warning: lexis.di.fct.unl.pt: maa owned process doing -bs
In-Reply-To: 
 <B6A1A9B09E52D31183ED00A0C9E0888C469A44@nctswashxchg.nctswash.navy.mil>
Errors-To: comp.lang.ada-admin@ada.eu.org
X-BeenThere: comp.lang.ada@ada.eu.org
X-Mailman-Version: 2.0
Precedence: bulk
List-Help: <mailto:comp.lang.ada-request@ada.eu.org?subject=help>
List-Post: <mailto:comp.lang.ada@ada.eu.org>
List-Subscribe: <http://ada.eu.org/mailman/listinfo/comp.lang.ada>,
	<mailto: comp.lang.ada-request@ada.eu.org?subject=subscribe>
List-Id: comp.lang.ada mail<->news gateway <comp.lang.ada.ada.eu.org>
List-Unsubscribe: <http://ada.eu.org/mailman/listinfo/comp.lang.ada>,
	<mailto: comp.lang.ada-request@ada.eu.org?subject=unsubscribe>
List-Archive: <http://ada.eu.org/pipermail/comp.lang.ada/>
Errors-To: comp.lang.ada-admin@ada.eu.org
X-BeenThere: comp.lang.ada@ada.eu.org
Xref: supernews.google.com comp.lang.ada:5495
Date: 2001-03-07T11:50:21+00:00

> procedure Xyz is
> 
>   opt_is : character := ' ';
> 
> begin
> 
>   while opt_is /= 'V' and then opt_is /= 'A' loop
>     Put( opt_prompt );
>     NEW_LINE;
>     Ada.Text_IO.Put_Line( "Please enter either a 'V' or an 'A' );
>     Get( opt_is );
>     opt_is := To_Upper(opt_is);
>   end loop;
> 
> end Xyz;

Lately I have been using enumerations and exceptions for this kind of
problem:

  type Options is (A, V);
  Option: Options;
  C: Character;
begin
  loop
    Put("Please enter either a 'V' or an 'A'");
    Get_Immediate(C);
    begin
      Option := Options'Value(C & "");
      exit;
    exception
      when Constraint_Error => null;
    end;
  end loop;

There is of course more to be said about "exception-oriented" programming. 
Let us save that for the Ada-Europe'2001 workshop ;-)

| |,| | | |RuaFranciscoTaborda24RcD 2815-249CharnecaCaparica 351+939354005
|M|A|R|I|O|
|A|M|A|D|O|DepartmentoDeInformaticaFCT/UNL 2825-114 Caparica 351+212958536
|A|L|V|E|S|                                                  fax 212948541
| | | | | |                 maa@di.fct.unl.pt                FCT 212948300