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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f43e6,37e6dbf5e31f6da0 X-Google-Attributes: gidf43e6,public X-Google-Thread: 103376,37e6dbf5e31f6da0 X-Google-Attributes: gid103376,public X-Google-Thread: 10db24,37e6dbf5e31f6da0 X-Google-Attributes: gid10db24,public X-Google-Thread: 1108a1,37e6dbf5e31f6da0 X-Google-Attributes: gid1108a1,public X-Google-Thread: ff6c8,37e6dbf5e31f6da0 X-Google-Attributes: gidff6c8,public From: eggert@twinsun.com (Paul Eggert) Subject: Re: Software Engineering News Brief Date: 1996/11/25 Message-ID: <57dogm$e45$1@shade.twinsun.com>#1/1 X-Deja-AN: 200764035 references: <55nqea$32a@news2.delphi.com> <3280BAFA.1B2F@email.mot.com> <563tle$cu7$1@shade.twinsun.com> <56lvss$r82@mulga.cs.mu.OZ.AU> <57916h$941$1@shade.twinsun.com> organization: Twin Sun Inc, El Segundo, CA, USA newsgroups: comp.lang.ada,comp.sw.components,comp.object,comp.software-eng,comp.edu Date: 1996-11-25T00:00:00+00:00 List-Id: dewar@merv.cs.nyu.edu (Robert Dewar) writes: > But to suggest that the standard built-in package have this kind of shaky > semantics, i.e. semantics that so obviously conflicts with one reasonable > expectation If the Ada standard couldn't specify semantics that obviously conflict with ``one reasonable expectation,'' then there wouldn't be a standard. The whole point of a standard is to specify one among several reasonable solutions to a problem. All I'm saying is that for calendars, the most reasonable solution is the Gregorian calendar. I agree that dates are not as simple as you think. But I'm afraid that a good deal of the calendrical misinformation in this thread has been posted by you: ``all countries agree for the Ada range of dates'' (they don't), ``the system of leap years has changed since [Pope Gregory's scheme]'' (it hasn't). Perhaps the Ada standardization committee chose the years 1901-2099 based on similar misunderstandings. That wouldn't be too surprising, as few computer language experts are also experts about timekeeping. It reminds me of the C standard's bug in leap second handling: the C standard allows for two leap seconds in the same minute (an impossibility), because the C committee misunderstood leap seconds. In any case, I urge the Ada standard committee to contact a genuine calendar implementation expert before making any future decisions in this area. A good choice would be Professor Ed Reingold of the University of Illinois, coauthor of ``Calendrical Calculations'', Software--Practice & Experience 20, 9 (1990), 899-928.