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=-0.8 required=5.0 tests=BAYES_00,INVALID_DATE autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,791ecb084fdaba75 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 1994-09-30 07:30:10 PST Path: bga.com!news.sprintlink.net!howland.reston.ans.net!EU.net!uknet!nplpsg!merlin.dclf.npl.co.uk!jrs From: jrs@merlin.dclf.npl.co.uk (Dr John Stockton) Newsgroups: comp.lang.ada Subject: Re: Types with physical dimension Date: Fri, 30 Sep 1994 10:17:54 Organization: National Physical Laboratory, UK Message-ID: References: <36deok$dce@gnat.cs.nyu.edu> <36e7sf$19ql@info2.rus.uni-stuttgart.de> NNTP-Posting-Host: merlin.dclf.npl.co.uk X-Newsreader: Trumpet for Windows [Version 1.0 Rev A] Date: 1994-09-30T10:17:54+00:00 List-Id: In article <36e7sf$19ql@info2.rus.uni-stuttgart.de> ucaa2385@iris3.csv.ica.uni-stuttgart.de (Peter Hermann) writes: >Robert Dewar (dewar@cs.nyu.edu) wrote: >: "Of course it would be nice to have more direct support for units" >Today, we are able to prevent an expression like >meter times meter giving meter. (you may substitute inch for meter :-) >We may allow meter times meter giving an_area_type. I missed the beginning of this. FYI, there was an article in European Journal of Physics earlier this decade AFAIR about a language, AMPERE?, which had types including physical dimensions for compile-time checking, and run-time limit (upper- & lower- bound) arithmetic. As a metrologist, I would find both very desirable, though I'd need "statistical" rather than "worst-case" arithmetic - and have implemented this to some extent in Borland Pascal. -- Regards, John Stockton. JRS@newton.npl.co.uk from off-site, or header address should now work. National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK Direct Phone +44 181-943 6087, Nearby Fax +44 181-943 7138