Re: The Emacs Calculator and calendar

[Jay Belanger]

> Good point.  So, as I understand it, the case you're worried
> about is a source where the author's practice is something
> like the following:
>
>    This book uses the Gregorian calendar for dates from 14
>    September 1752 onwards, and the Julian calendar starting
>    on January 1 for dates before that.  The calendar is not
>    otherwise indicated.
>
> No doubt some books exist like that, but in my experience
> the following sorts of rules are more typical:
>
>   "For the purposes of this book, all dates are given using
>    the modern Gregorian calendar unless specifically
>    followed by the O.S. designation."
>      -- David Marley, Wars of the Americas, ABC-CLIO (2008),
>       page xiii.

As much as there is one, the consensus in this discussion seems to be
that the pure Gregorian calendar should be the default, but the user
should be able to explicitly ask for something else (from a choice of
other options and, perhaps, some more general settings could be
available).  Which makes your typical situation the default and the 
"no doubt ... exist" situation an option that the user can explicitly
ask for.
I'll make sure that something like that is in Calc after the next Emacs
release.  

(Note that Isaac Newton's birthday is December 25 in the Julian
calendar, so some sort of hybrid calendar would be desirable for those
who want Grav-mass to be that date.:)