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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,6b6619eb9cada212
X-Google-Attributes: gid103376,public
From: Tucker Taft <stt@averstar.com>
Subject: Re: Help me to chose between ADA 95 and C++
Date: 1999/12/14
Message-ID: <3856A1F5.4E360DC@averstar.com>#1/1
X-Deja-AN: 560663835
Content-Transfer-Encoding: 7bit
Sender: news@inmet.camb.inmet.com (USENET news)
X-Nntp-Posting-Host: houdini.burl.averstar.com
References: <01bf37fb$a91afb60$0564a8c0@IS-D2D04C.test>
 <B46461D2.259F%Harald.Schmidt@tomcat.de>
 <829rbv$a8m$1@nntp6.atl.mindspring.net> <01bf3e32$0b9dc880$022a6282@dieppe>
 <385112AE.7E2CFA9@rdel.co.uk>
 <Pine.BSF.4.21.9912131540530.6417-100000@shell5.ba.best.com>
 <38564CD6.F13F69FB@rdel.co.uk> <m3u2llv5rt.fsf@kiuk0156.chembio.ntnu.no>
 <uwvqhbbxy.fsf@gsfc.nasa.gov>
X-Accept-Language: en
Content-Type: text/plain; charset=us-ascii
Organization: AverStar (formerly Intermetrics)  Burlington, MA  USA
Mime-Version: 1.0
Newsgroups: comp.lang.ada
Date: 1999-12-14T00:00:00+00:00
List-Id: <comp.lang.ada>

Stephen Leake wrote:
> 
> Preben Randhol <randhol@pvv.org> writes:
> 
> > | Interestingly, many of the OO related pitfalls are evident in Ada 95 and
> > | C++, because the way the two languages work is not actually that
> > | different, for example attempting to override a method, but mis-typing
> > | the name in the derived class making it a new method rather than an
> > | overriden one.
> >
> > What is your solution to this? To me it sounds like the programmer
> > does not proof-read his code if this is a _real_ problem. :-)
> 
> I just wasted a couple of hours on a closely related problem, which I
> propose we call "the snark effect" (see thread "hunting snarks"). I
> changed the profile of the base type operation (one parameter changed
> from "in out" to "access" to avoid an accesibility problem). But I
> forgot to change one of the operations in one of the (many) derived
> types. In similar situations, Ada catches such errors (ie, change spec
> but forget to change body). I'd like Ada to catch this as well.

A trio of pragmas have been proposed for eventual standardization that will
allow the compiler to catch this problem.  Basically you will be able
to indicate whether a given operation is or is not presumed to override
some inherited operation.  See the following AI for details:

    http://www.ada-auth.org/cgi-bin-acats/cvsweb.cgi/AIs/AI-00218.DOC?rev=1.3
> 
> -- Stephe

-- 
-Tucker Taft   stt@averstar.com   http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions  (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.)   Burlington, MA  USA