On Fri, 13 Aug 2010 21:49:19 +0000, john gilmore wrote:
>
>| That would be a proleptic Gregorian date?
>
>and the answer to his question is that the dates of all days that occur before
>a calendar's epoch origin are proleptic for that calendar by definition.
>Their day numbers are negative. The use of a fullword for Gregorian day
>values provides the capacity for specifying dates about 10 million years
>before and after the Gregorian epoch origin, 0000 December 31 or 0001 January
>1, depending upon one's preference for zero-origin or one-origin subscripting
>and the like.
>
I was more thinking of 1582. Wikipedia (which is always right
except when it disagrees with you) says:
http://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar
The proleptic Gregorian calendar is produced by extending
the Gregorian calendar backward to dates preceding its
official introduction in 1582.
>One of the most dispiriting things about the money and time that were spent on
>Y2K remediation is that it was almost all done very badly: all the old data
>representations, their calendar-arithmetic deficiencies, and the errors they
>give rise to were lovingly preserved.
>
I'll agree enthusiastically except where the change could be
made in a compatible manner, altering no sizes, displacements,
nor content of existing data bases. One example might be
that where Dec. 31, 1999 is represented as x'99365', Jan.
1, 2000 could (have) been represented as x'A0001' in a field
of the same size and sorting in a consistent order. Or am
I inviting the documented y2.01k glitch?
-- gil
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