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: 103376,92471489ebbc99c6 X-Google-Attributes: gid103376,public From: adam@irvine.com Subject: Re: Y2K Issues Date: 1998/10/28 Message-ID: <718200$efa$1@nnrp1.dejanews.com>#1/1 X-Deja-AN: 406049811 References: <362B53A3.64E266AB@res.raytheon.com> <36365724.EF1CC215@maths.unine.ch> X-Http-Proxy: 1.0 x3.dejanews.com:80 (Squid/1.1.22) for client 192.160.8.21 Organization: Deja News - The Leader in Internet Discussion X-Article-Creation-Date: Wed Oct 28 21:23:12 1998 GMT Newsgroups: comp.lang.ada X-Http-User-Agent: Mozilla/3.0 (X11; I; Linux 2.0.34 i686) Date: 1998-10-28T00:00:00+00:00 List-Id: In article <717kpq$7cv$1@platane.wanadoo.fr> "Jean-Pierre Rosen" writes: > > Gautier.DeMontmollin@maths.unine.ch a \351crit dans le message ... > >"Standard" depends on what usage is expected from Ada language... > >Since it is a powerful and comfortable tool in many other domains than > >real-time systems (I think in present context to statistics or nature > >sciences), the 1901..2099 range seems to me _a bit_ narrow. > >Apparently - as you write - it's not a problem of sparing some bits or > >adding lots of leap years code. Of course it's very easy to write a sort > >of Long_Calendar from GNAT library sources but I already see people > >using the wrong Calendar etc... But maybe there are solid reasons for that > >range, like the ability of doing 8-bit arithmetics (199<256) with the > years... > > > You have to put some bounds somewhere. Allowing dates before 1600 > for example (actually 1543 ? not sure) is really asking for trouble > (that's when the Julian calendar switched to Gregorian). To make things worse, there's no one date when the calendar switched to Gregorian. IIRC, the Catholic nations all switched when Pope Gregory designed the change, but everyone else lagged behind. Britain didn't make the switch until the mid-18th century. Plus, in Sweden, I seem to recall reading that they tried to be clever about how they made the change and then messed it up, with the result that one year they had to add a 30th day to February. So if you're going to extend the Calendar package to handle years going back several centuries, you have to make sure the package allows February 30, at least for one specific year that I don't remember, if you're dealing with Swedish dates. Of course, even the current Calendar package is going to have problems with Russian dates, since they stayed with the Julian calendar until 1918 (with the result that the October Revolution really happened in November). I suppose it was a flaw in the design of Ada that the designers didn't consider that case---perhaps they should have made the year subrange 1919..2099 to avoid this problem. Next, someone will be asking why there's no Ada.Calendar.Jewish in the standard . . . -- Adam -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own