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=-0.3 required=5.0 tests=BAYES_00, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,cc4f25d878383cc X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-12-07 06:36:19 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!bloom-beacon.mit.edu!newsswitch.lcs.mit.edu!newsfeed.mathworks.com!cyclone.swbell.net!bos-service1.ext.raytheon.com!dfw-service2.ext.raytheon.com.POSTED!not-for-mail Message-ID: <3C10D3D8.DF189A55@sparc01.ftw.rsc.raytheon.com> From: Wes Groleau Reply-To: wwgrol@sparc01.ftw.rsc.raytheon.com X-Mailer: Mozilla 4.77 [en] (Windows NT 5.0; U) X-Accept-Language: en,es-MX,es,pt,fr-CA,fr MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Dimensionality Checking (Ada 20XX) References: <3C0A5054.E74A82E7@worldnet.att.net> <9ugs4v$8d7lj$1@ID-25716.news.dfncis.de> <3c0cc931.16965562@News.CIS.DFN.DE> <36c6f8dd.0112061152.333c9de@posting.google.com> <3C0FF376.2DC0C3E4@usa.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Fri, 07 Dec 2001 09:36:08 -0500 NNTP-Posting-Host: 151.168.144.162 X-Complaints-To: news@ext.ray.com X-Trace: dfw-service2.ext.raytheon.com 1007735778 151.168.144.162 (Fri, 07 Dec 2001 08:36:18 CST) NNTP-Posting-Date: Fri, 07 Dec 2001 08:36:18 CST Organization: Raytheon Company Xref: archiver1.google.com comp.lang.ada:17565 Date: 2001-12-07T09:36:08-05:00 List-Id: Mark Lundquist wrote: > > "Wes Groleau" wrote .... > > > Accel : Magnitude; > > > for Accel'Unit use > > > ISO_Metric_Units.Meter / ISO_Metric_Units.Second**2; > > > > In some cases, might there be multiple ways to describe > > the units? Speed is Acceleration * Time but it is also > > Distance / Time. > > Right, which is why (a) the concepts of "unit" and of "dimension" need to be > loosely coupled (this is missing from the proposals I've seen so far), and > then (b) you have to distinguish between base and derived dimensions. I guess what I mean is that the compiler would have to have some smarts to be able to figure out all the numerous ways of deriving a derived dimension--including from other derived dimensions. -- Wes Groleau http://freepages.rootsweb.com/~wgroleau