Return-Path: Resent-From: cbmvax!uunet!PICA.ARMY.MIL!protin Resent-Message-Id: <9107121843.AA06117@relay1.UU.NET> 2 Sep 90 1:13 EDT From: cbmvax!uunet!prc.unisys.com!dave Message-Id: <9008311526.AA00582@gem> Date: Fri, 31 Aug 90 11:26:15 -0400 To: major@pta.oz.au Cc: lojban-list@snark.thyrsus.com In-Reply-To: Major's message of Thu, 30 Aug 90 11:34:40 +0800 <9008300413.21854@munnari.oz.au> Subject: Re: times, dates, images, and S-W Resent-Date: Fri, 12 Jul 91 14:38:27 EDT Resent-To: John Cowan Status: RO X-From-Space-Date: Fri Jul 12 17:27:10 1991 X-From-Space-Address: cbmvax!uunet!PICA.ARMY.MIL!protin > > [regarding] conventions for time and date representations [as > > discussed by] John Hodges & Bob > > [...] > > [methods] I currently use for representing dates: > > [...] > > (2) as year followed by two digit number of month followed by > > two digit day of the month as in > > 900806 or 19900806 > ^^^^^^ > > WARNING: This method will break badly in just 10 years. Is 010202 > 01 February 2002, 01 February 1902, 02 February 2001 or 02 Febraury 1901? It's February 2, of either 1901 or 2001. In normal circumstances the context makes it pretty obvious which is meant; to be precise, prepend the 19 or the 20. Your other interpretations make no sense at all under this scheme; they're the British interpretations of 01/02/02. I've been using the yymmdd scheme for years. A friend of mine showed it to me, and I found it very convenient, and began using it (on my own private papers and files; it's not worth the effort to make other people learn to read my dates). A big advantage is that numerical sorts work just fine. Another advantage is that it doesn't favor either American-style dates (mm/dd/yy) or British-style dates (dd/mm/yy), it's more logical than either, and it can be equally easily explained to members of both groups. Yes, the method will break in ten years, but it won't break badly. It will sort into two chunks, one before the century mark, and one after. A single IF statement can take care of this. For anything spanning more than one century break, you would of course use all four digits of the year anyway. > YOU have a convention of yymmdd, but there is nothing which makes > that obviously better than ddmmyy. Which you are using is only obvious > in those years when yy>31. What? You've misunderstood something, but I'm not sure just what. I think you're assuming that people are going to start mixing the three kinds of dates, and leaving out the "/" or "-" separators when they use British or American dates. Both are improbable. Personally, I'd find it more legible to write today's date as 90 08 31 instead of 900831, but only slightly. Anyway, it bugs me that so many programming languages that can't cope with spaces in numbers; Fortran does still retain some (albeit very few) advantages. -- Dave Matuszek (dave@prc.unisys.com) -- Unisys Corp. / Paoli Research Center / PO Box 517 / Paoli PA 19301 -- Any resemblance between my opinions and those of my employer is improbable. < You can put a mouse on an IBM. And you can put a radio on a motorcycle. >