Rob Weir's article on Microsoft XML date problems

["David A. Wheeler" <dwheeler@dwheeler.com>]

FYI:
Rob Weir's "A Leap Back" (Thursday, October 12, 2006) at
http://www.robweir.com/blog/2006/10/leap-back.html
notes a problem with Microsoft's XML format: It REQUIRES that
implementations MISCALCULATE the year 1900. Excel
thinks that 1900 was a leap year, when it clearly isn't, under Gregorian rules...
and since Microsoft's XML is just "whatever Excel does", it
gets it really, really wrong.
(I suspect it also forbids applications to be more capable than
Excel by forbidding the representation of dates before 1900.)

OpenFormula avoids this.
We do NOT require that implementations get 1900 WRONG.
Because we have multiple different applications, we can easily
compare results; this particular issue was noticed and addressed long ago.
What's more, because OpenDocument represents dates as, well,
dates, in many circumstances the problem disappears.

--- David A. Wheeler