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,d2c21e8238e985b5 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2002-05-28 18:16:19 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!postnews1.google.com!not-for-mail From: dewar@gnat.com (Robert Dewar) Newsgroups: comp.lang.ada Subject: Re: Extended modal types Date: 28 May 2002 18:16:19 -0700 Organization: http://groups.google.com/ Message-ID: <5ee5b646.0205281716.5478fee@posting.google.com> References: <3CEDFF90.B94D7E32@yahoo.com> <5ee5b646.0205250757.60c9715a@posting.google.com> <874rgwt6jf.fsf@deneb.enyo.de> <3CF1BE0C.8020704@attbi.com> <87elfyb0iz.fsf@deneb.enyo.de> <3CF2C6AF.60607@attbi.com> NNTP-Posting-Host: 205.232.38.244 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Trace: posting.google.com 1022634979 28508 127.0.0.1 (29 May 2002 01:16:19 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: 29 May 2002 01:16:19 GMT Xref: archiver1.google.com comp.lang.ada:24885 Date: 2002-05-29T01:16:19+00:00 List-Id: "Robert I. Eachus" wrote in message news:<3CF2C6AF.60607@attbi.com>... > Florian Weimer wrote: > You are probably thinking of public-key encryption where the keys and > modulii are too big for ordinary modular types anyway. I was thinking > of many algorithms that use modular arithmetic to introduce > non-linearity, for example multiplying two four-bit nibbles mod 17. In > cases like this, the modulus is a static part of the algorithm > definition, and needs to be prime for invertability. The fact that there are many algorithms which need a particular datatype with some particular properties is NOT a reason for putting the type into the language as a primitive type. All these arguments about cryptography and hashing were made in the URG meeting which rejected the generalization of unsigned wrap around types to general non-binary modulus values overwhelmingly. I think the URG had it right and Ada 95 has it wrong. There are lots and lots of types that belong in the language long before non-binary modular types (one that jumps to mind as clearly more important is multiple precision integer arithmetic -- but I would not put that in either :-)