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=0.5 required=5.0 tests=BAYES_00,TO_NO_BRKTS_PCNT
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,fa18fb47ddd229a7,start
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-12-09 21:48:57 PST
Path: 
 archiver1.google.com!news2.google.com!newsfeed2.dallas1.level3.net!news.level3.com!news-out.visi.com!petbe.visi.com!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed.icl.net!newsfeed.fjserv.net!kibo.news.demon.net!news.demon.co.uk!demon!not-for-mail
From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Proposed change to BC iterator parameters
Date: 10 Dec 2003 05:46:11 +0000
Organization: Pushface
Sender: simon@smaug.pushface.org
Message-ID: <x7viskpz0m4.fsf@smaug.pushface.org>
NNTP-Posting-Host: pogner.demon.co.uk
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: news.demon.co.uk 1071035336 21415 62.49.19.209 (10 Dec 2003 05:48:56
 GMT)
X-Complaints-To: abuse@demon.net
NNTP-Posting-Date: Wed, 10 Dec 2003 05:48:56 +0000 (UTC)
User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.1
Xref: archiver1.google.com comp.lang.ada:3296
Date: 2003-12-10T05:46:11+00:00
List-Id: <comp.lang.ada>

Martin Krischik <krischik@users.sourceforge.net>'s AdaCL
(http://adacl.sourceforge.net) includes changes to some of the Booch
Component iterators. For example,

   generic
      type Param_Type is private;
      with procedure Apply (Elem : in Item;
                            Param : in Param_Type;
                            OK : out Boolean);
   procedure Visit_With_In_Param (Using : in out Iterator'Class;
                                  Param : in Param_Type);
   --  Call Apply with a Parameter for each Item in the Container to
   --  which the iterator Using is bound. The iteration will terminate
   --  early if Apply sets OK to False.

Martin proposes

      type Param_Type (<>) is private;

but it occurs to me that the code ought to be

      type Param_Type (<>) is limited private;

As I understand it, this allows users much more freedom (you can even
use a tagged type provided you instantiate with Tagged_Type'Class).

But are there any downsides? (backward incompatibility being something
to for me to avoid!)

-- 
Simon Wright                               100% Ada, no bugs.