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: 103376,38fc011071df5a27 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-05-31 07:00:27 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!headwall.stanford.edu!newshub.sdsu.edu!newsfeed2.earthlink.net!newsfeed.earthlink.net!newsfeed.news2me.com!newsfeed.icl.net!newsfeed.fjserv.net!kibo.news.demon.net!demon!btnet-peer0!btnet-peer!btnet!news-hub.cableinet.net!blueyonder!internal-news-hub.cableinet.net!news-binary.blueyonder.co.uk.POSTED!53ab2750!not-for-mail User-Agent: Microsoft-Entourage/10.1.1.2418 Subject: Re: Ideas for Ada 200X From: Bill Findlay Newsgroups: comp.lang.ada Message-ID: References: <6a90b886.0305262344.1d558079@posting.google.com> <3ED41344.7090105@spam.com> <3ED46D81.FF62C34F@0.0> <3ED46E07.4340CABC@0.0> <3ED4F3FD.A0EF7079@alfred-hilscher.de> Mime-version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-transfer-encoding: 7bit Date: Sat, 31 May 2003 14:59:22 +0100 NNTP-Posting-Host: 80.195.75.181 X-Complaints-To: abuse@blueyonder.co.uk X-Trace: news-binary.blueyonder.co.uk 1054389626 80.195.75.181 (Sat, 31 May 2003 14:00:26 GMT) NNTP-Posting-Date: Sat, 31 May 2003 14:00:26 GMT Organization: blueyonder (post doesn't reflect views of blueyonder) Xref: archiver1.google.com comp.lang.ada:38216 Date: 2003-05-31T14:59:22+01:00 List-Id: On 31/5/03 14:42, in article BAFE6FC5.2ECD%yaldnifw@blueyonder.co.uk, "Bill Findlay" wrote: > > 3. X := 0.5*(idem + a/idem); > > gives a lot more expressive power than update-in-place operations, but > allows the latter to be implemented very easily in most cases that > significant efficiency gains are possible ... > > The idem notation also documents the programmer's intention more clearly in > the cases (such as 3) in which the RHS subexpression is necessarily the same > as the LHS, but which do not fit the limitations of a ?:= operation. It occurs to me that if I had given the example: 4. X = idem * (2.0 - a*idem); then at least one computer would be able to implement it in a single instruction ! 8-) -- Bill-Findlay chez blue-yonder.co.uk ("-" => "")