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,a3bf872bb81a1f2b X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-12-11 20:29:34 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!newsfeed.direct.ca!look.ca!newsfeed1.earthlink.net!newsfeed.earthlink.net!newsmaster1.prod.itd.earthlink.net!newsread1.prod.itd.earthlink.net.POSTED!not-for-mail Message-ID: <3C16DD1F.E768B33@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: ASCL a doomed idea? References: <7RQP7.4406$Yy.272014@rwcrnsc53> <9v0crv$bo2bi$2@ID-25716.news.dfncis.de> <3C13D980.748CCCDA@acm.org> <9v37s0$cdmva$3@ID-25716.news.dfncis.de> <3C153926.102B17B1@boeing.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Wed, 12 Dec 2001 04:29:31 GMT NNTP-Posting-Host: 209.86.204.28 X-Complaints-To: abuse@earthlink.net X-Trace: newsread1.prod.itd.earthlink.net 1008131371 209.86.204.28 (Tue, 11 Dec 2001 20:29:31 PST) NNTP-Posting-Date: Tue, 11 Dec 2001 20:29:31 PST Organization: EarthLink Inc. -- http://www.EarthLink.net X-Received-Date: Tue, 11 Dec 2001 20:29:33 PST (newsmaster1.prod.itd.earthlink.net) Xref: archiver1.google.com comp.lang.ada:17812 Date: 2001-12-12T04:29:31+00:00 List-Id: Ted Dennison wrote: > > Anyway, JC01 presents an unsafe style iterator. His comments say it could go > either way, but if its safe, there's no sense in supplying the list with it like > all JC01's routines do, so I think his presentation only makes sense for an > unsafe iterator. For an unsafe iterator, I think "Position" is reasonable, as it > at least underlines that you can't expect the compiler to do all your checking > for you like you would with a true iterator. It presents a specification that doesn't bias the implementation. If you leave the list parameters off, you can't have an unsafe implementation, but putting them in doesn't prevent a safe implementation. > Which one we use is something that still needs to be decided. Perhaps there > hasn't been much discussion about this because everyone is happy with the way > the latest Strawman does it (safe)? I'm not too concerned either way. Complete safety means insertion and deletion are O(M) in time, where M is the number of Locations in existence. The additional protection this gets you over mostly safe Locations seems to be against pathological cases, misuse of a list of a kind that I've never actually seen in practice (and I've seen some pretty poor code using lists with completely unsafe Locations). So, I'm not sure complete safety is worth the effort, but I won't be bothered if it's deemed essential for the standard list. -- Jeff Carter "My brain hurts!" Monty Python's Flying Circus