From: Stan Heckman <stan at stanheckman.com>
> Okay. If we are going to choose historical dates instead of leap
> seconds, perhaps method comments should indicate that historical times
> measure position of the sun, while the modern times measure the rate
> at which clocks run. We have two classes, Date and Time. Date can
> unambiguously be the (possibly proleptic) Gregorian date. Time is the
> difficult case. Perhaps Time's comment could read "...UTC after 1972,
> solar time at Greenwich before." This should make it obvious that we
> aren't supporting one second accuracy for durations extending before
> 1972.

That sounds like a good solution to me.

Date should definitely use the propleptic Gregorian calendar. Propleptic
calendars - extending forwards and backwards in time - are the only sensible
choice.

Many computer systems get this wrong. They only allow one date of change
from Julian to Gregorian. In the real world, different locations changed
calendars at different times, anywhere from 1582 to this century.

Regards,

Eric Ulevik