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-Thread: 103376,6339fea48a1b8cda X-Google-Attributes: gid103376,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news4.google.com!out04b.usenetserver.com!news.usenetserver.com!in04.usenetserver.com!news.usenetserver.com!nx01.iad01.newshosting.com!newshosting.com!69.16.185.51.MISMATCH!tmp-post01.iad!news.highwinds-media.com!roadrunner.com!not-for-mail From: "John B. Matthews" Newsgroups: comp.lang.ada Subject: Re: Enumeration representation clause surprise. Organization: home References: <770ae1af-b9fd-4c8a-915c-a5cb3ea8fc81@c65g2000hsa.googlegroups.com> <87hcbybazk.fsf@willow.rfc1149.net> <878wx9bdda.fsf@willow.rfc1149.net> User-Agent: MT-NewsWatcher/3.5.2 (PPC Mac OS X) Date: Sat, 14 Jun 2008 07:48:33 -0400 Message-ID: NNTP-Posting-Host: 24.33.128.99 X-Complaints-To: abuse@rr.com Xref: g2news1.google.com comp.lang.ada:701 Date: 2008-06-14T07:48:33-04:00 List-Id: In article <878wx9bdda.fsf@willow.rfc1149.net>, Samuel Tardieu wrote: > Peter Hermann: > > > Samuel Tardieu wrote: > > > 26. X1 at 0 range 0 .. -1; -- Minus 1 !! > > > > this is a null range: LRM3.5(4) > > Exactly. And this null range can represent 2^0 = 1 value. Which is the > case in this example. But null (o, \u00F8) is not zero. The range 0 .. -1 is "a null range, and [it] specifies an empty set of values." [LRM3.5(4)] If I understand it correctly, the value 2^0 is the power set of o, {o}, a set with one element, which is the empty set. John -- John B. Matthews trashgod at gmail dot com home dot woh dot rr dot com slash jbmatthews