[Ocaml-lib-devel] Re: [Caml-list] ANNOUNCE: Library for handling Gregorian date calculations

[Julien S. <Jul...@lr...>]

On Fri, 29 Oct 2004, Richard Jones wrote:

> On Thu, Oct 28, 2004 at 11:33:30PM -0400, N. Owen Gunden wrote:
> > Bump.  Rich?
>
> Ah, sorry - this discussion moved to ocaml-lib-devel.  I cc'd
> caml-list, but it seems to have been spam filterered.
>
> http://sourceforge.net/mailarchive/forum.php?thread_id=5833296&forum_id=29880

ok. I didn't know this mailing list.

I give my point of view. I try to be neutral ;-).

1) I download "cf" (version 0.4) and it seems that Cf_date is now called
Cf_gregogian.

2) Cf_gregorian only defines 6 functions to convert a gregorian date to
the Julian Day and conversely. These functions exists in the module Date
of calendar. The calendar algorithms seem to be more efficient. However
they only work in the date in [January, 1st 4713 BC; January 22th, 3268
AC] (against [12 Aug -2937947 CE; 27 Feb 2935093] for Cf_gregorian).

It seems that these functions don't exist in GregorianDate.

3) Almost the functions of GregorianDate are available in the module Date
of calendar except:
	(a) those dealing with the "business week";
	(b) nth_weekday_of_month;
	(c) the optional parameter ?month of days_in_year.
But (b) and (c) will be available in the next release of calendar (soon !).
At this day, I don't understand what is a "business week" :-(.

4) Date in calendar deals with the gregorian calendar *and* the julian
calendar. I think it is a pro in some applications and a cons in others...

5) Some operations of Date are not available in GregorianDate. In
particular, a lot of arithmetics operations and the coercions with Unix
(of the stdlib) are not provided. I think that these functions are useful.

5) Calendar doesn't only deal with dates but also with times. It
also provides printers. More details in the doc:

	http://www.lri.fr/~signoles/prog/calendar/doc/index.html

Conclusion:
===========
I think calendar is more complete that GregorianDate and Cf_gregorian.
I'm not sure but it also seems to be the oldest.
First release and announce on the caml-list: 2003-07-11, see here:

	http://caml.inria.fr/archives/200307/msg00108.html


Cheers,
Julien
-- 
mailto:Jul...@lr... ; http://www.lri.fr/~signoles
"In theory, practice and theory are the same,
but in practice they are different" (Larry McVoy)