Zefram scripsit: > There is the alternate point of view that the calendar in actual civil use > in a particular locality, changing between different arithmetic calendars > at different times, constitutes an unpredictable observational calendar. > Perhaps we need a concept of "calendar zone" analogous to time zone, > with a calendar zone database to match.
Claus Tøndering's excellent Calendar FAQ contains a first cut at such a thing in Section 2.2.4. See http://www.tondering.dk/claus/cal/node3.html#SECTION00324000000000000000 As one would expect, the information is less than 100% reliable, as sources disagree. I particularly like this one: # Sweden has a curious history. Sweden decided to make a gradual change # from the Julian to the Gregorian calendar. By dropping every leap year # from 1700 through 1740 the eleven superfluous days would be omitted and # from 1 Mar 1740 they would be in sync with the Gregorian calendar. (But # in the meantime they would be in sync with nobody!) # # So 1700 (which should have been a leap year in the Julian calendar) # was not a leap year in Sweden. However, by mistake 1704 and 1708 # became leap years. This left Sweden out of synchronisation with both # the Julian and the Gregorian world, so they decided to go back to the # Julian calendar. In order to do this, they inserted an extra day in # 1712, making that year a double leap year! So in 1712, February had # 30 days in Sweden. # # Later, in 1753, Sweden changed to the Gregorian calendar by dropping # 11 days like everyone else. Note that the Islamic calendar is truly observational: a month starts when an actual human observer makes a lunar observation, and all Islamic calendars purporting to show the future are merely best-effort approximations. This calendar is official in some but not all Muslim countries, even for civil purposes. -- My corporate data's a mess! John Cowan It's all semi-structured, no less. http://www.ccil.org/~cowan But I'll be carefree [EMAIL PROTECTED] Using XSLT On an XML DBMS.
