That appears to be a Julian day referenced to the start of the year. My
understanding of a Julian day number is that it is the number of days since
the start of the current Julian period, which started noon Jan 1 4713 BC.
Noon of Dec 31 1998 was the beginning of JD 2,451,179. There is an
algorithm for calculating this number from a given date in the Gregorian
Calendar, our present calendar, but I don't have it at hand. It requires
the use of a floor or ceiling function, the nearest integer smaller (or
greater) than a given decimal number. The formula accounts for leap years
and the days in each month. It also starts a year on March 1, so February
is the last month, and the formula truncates its length correctly. I
implemented the formula in Forth using integers, but it was long ago -- .
The above info is from "The World Almanac and book of Facts for 1999"
published by World Almanac Books.
----- Original Message -----
From: <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, October 28, 1999 10:56 PM
Subject: [REBOL] epoch? Re:(6)
> Hi,
>
> Try this:
>
> >> t: now/date
> == 28-Oct-1999
> >> t/julian
> == 301
> >> 1-jan-1999 + 300
> == 28-Oct-1999
>
> - jim
>
>
> At 09:56 PM 10/28/99 -0700, you wrote:
> >REBOL *must* be basing dates on a stored Julian day number. They should
> >give us a word 'julian that returns the julian day no for a given date,
and
> >some other word to convert it to a date. The Julian day number accounts
for
> >leapyears, number of days in each month, etc. There are a number of
"epoch"
> >dates corresponding to Julian day number zero. EG 1 jan 1978, another in
the
> >15 or 14 century, etc.
> >
> >----- Original Message -----
> >From: <[EMAIL PROTECTED]>
> >To: <[EMAIL PROTECTED]>
> >Sent: Thursday, October 28, 1999 8:53 PM
> >Subject: [REBOL] epoch? Re:(4)
> >
> >
> > > You mean to use 31-12-1969
> > >
> > > At 10:40 PM 10/28/99 -0400, you wrote:
> > > >Elegant, except it's one day off ... should be now - 12-31-1969 *
86400,
> > > >except that gives an invalid date.
> > >
> > >
>
>
