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-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,1dd28d5040ded1f8 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-05-13 12:16:30 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!paloalto-snh1.gtei.net!lsanca1-snf1!news.gtei.net!newsfeed2.earthlink.net!newsfeed.earthlink.net!stamper.news.pas.earthlink.net!newsread2.prod.itd.earthlink.net.POSTED!not-for-mail Message-ID: <3CE01103.E90B96B3@acm.org> From: Jeffrey Carter X-Mailer: Mozilla 4.7 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Announce: Grace project site operational References: <3CD88FBD.4070706@telepath.com> <3CD91E31.1060004@telepath.com> <3CDBD673.FF452A3D@otelco.net> <3CDD75C7.36C6ADCF@acm.org> <4519e058.0205130744.2602e251@posting.google.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Mon, 13 May 2002 19:16:33 GMT NNTP-Posting-Host: 63.184.19.60 X-Complaints-To: abuse@earthlink.net X-Trace: newsread2.prod.itd.earthlink.net 1021317393 63.184.19.60 (Mon, 13 May 2002 12:16:33 PDT) NNTP-Posting-Date: Mon, 13 May 2002 12:16:33 PDT Organization: EarthLink Inc. -- http://www.EarthLink.net Xref: archiver1.google.com comp.lang.ada:23974 Date: 2002-05-13T19:16:33+00:00 List-Id: Ted Dennison wrote: > > Jeffrey Carter wrote in message news:<3CDD75C7.36C6ADCF@acm.org>... > > The imported type Element should have the "=" operation imported for it. > > > > The "=" operations for types List and Iterator should be visible to > > clients of the package. > > I'd like to see more discussion on this point. The way I remember it, > we didn't want to add a lot of generic parameters that >%99 of the > time would not be used. I can't remember overloading "=" myself, ever. > This goes back to the "default generic parameters" issue, but I > digress. However, I seem to remember some folks saying that not > importing "=" this way causes the built-in equality to reassert itself > even after its been overridden. Am I remembering this correctly? Yes. For this to be a general-purpose package, it should work correctly if the client has a user-defined "=" for the actual type used for Element. Since the package does use "=" for this type (in "=" for List), it must be imported to work properly. Luckily, we can default subprograms ("is <>"), so this adds no additional burden to the instantiation for most users. Since types List and Iterator are private, we are telling the client that "=" for these types is meaningful. Since the predefined "="s for these types are not meaningful, that means the client must have visibility to the package-defined versions. Currently these versions are declared in the private part of the package, so the client does not have visibility to them. They should be moved to the visible part of the specification so the client may call them. -- Jeff Carter "Now go away or I shall taunt you a second time." Monty Python & the Holy Grail