WP34s: date functions and negative years

[Dieter]

(01-18-2015 08:22 AM)walter b Wrote:  I tend to vote for 1 or 3. 1 would be a clean solution.

Right. If implemented correctly, both ways essentially use the same code with (1) resp. without (3) rejecting years before 8 A.D.

I think the latter decision should be up to the user. There are uses for such a proleptic Julian calendar (that's why it exists):

(01-18-2015 08:22 AM)walter b Wrote:  (...) 3 would allow for calculating weekdays for all recorded events in history of mankind.

It's not because of weekdays (if they had existed the way we use them today), it simply makes date calculations in that era possible.

That's why I vote for solution 3.

Any user is free not to use the date functions for years before 8 A.D. where actually various other calendars were used around the world. Years before –4712 should return an error message since below that point the used formulas (and the resulting negative Julian day numbers) are not defined.

Dieter