Re: Julian Dates package?

[Mike Stark <michael.e.stark@gsfc.nasa.gov>]

Keith Thompson wrote:
> 
> Mike Stark <michael.e.stark@GSFC.NASA.GOV> wrote:
> > I suggest using package Calendar, since it provides subtraction operator
> > for two absolute times, yielding elapsed times.  To compute number of
> > days, create a birthdate and current date of type calendar.time, with
> > the seconds of day set to zero.  This will give you a (fixed point)
> > number of seconds.  Divide that number by 86,400 and you now have
> > the number of days.
> 
> That's not guaranteed to work.  The subtraction operation returns a
> result of type Duration, which is a fixed-point type with a minimum range
> of -86400.0 .. +86400.0 (i.e., +/- 1 day).  Thus, you can't portably
> subtract two Calendar.Time values more than a day apart.
> 
> --
> Keith Thompson (The_Other_Keith) kst@aonix.com <http://www.aonix.com> <*>
> TeleSo^H^H^H^H^H^H Alsy^H^H^H^H Thomson Softw^H^H^H^H^H^H^H^H^H^H^H^H^H Aonix
> 10251 Vista Sorrento Parkway, Suite 300, San Diego, CA, USA, 92121-2706
> "SPOON!" -- The Tick
OOPS!  You are absolutely right!  We have a time utilities package that
exports a time type that is valid from 1901 through 2099, the same range
as Calendar.TIME, and allows the computation of elapsed time as a
floating point number of seconds.  If anyone is interested in our time
packages feel free to send me an e-mail.

Mike