sorting by date senile?

[FlexibleLearning at aol.com]

> convert "01/03/1937" to dateitems
> I got invalid date  ;(
>
> Maybe we should switch to stardate ;))
 
I can't offer Stardate to you, but Julian dates handle the number of days  
since noon 4713 BC January 1. These were posted by _joel.guillod at net2000.ch_ 
(mailto:joel.guillod at net2000.ch)  on 16 Apr  2004 and may provide you with the 
tools... At least they avoid the 'invalid  date' syndrome!
 
 


/*  date.julian return the julian count, i.e. days since 24.11.-4713
@param d is  the day
@param m is the month
@param y is the year
@returns is the  julian count
*/
function date.julian d,m,y
return  (1461*(y+4800+(m-14) div 12)) div 4+(367*(m-2-12*((m-14) div 12))) 
div  12-(3*((y+4900.0+(m-14) div 12) div 100)) div 4+d-32075
end  date.julian
 
Example:
answer date.julian 13,11,2001
 

/* get date.julian2DayOfWeek(aJulian)
@purpose Returns the day of  the week according to: 1..7 for Sunday..Saturday
@param aJulian is the julian  number.
*/
function date.julian2DayOfWeek aJulian
--    // returns 1..7 for Sunday..Saturday
return  (aJulian+1) mod 7 + 1
end date.julian2DayOfWeek
 
Example:
answer date.julian2DayOfWeek 2452227
 

/* date.julian2DMY aJulian, at d, at m, at y
@purpose Set the day, month year  according to the julian date aJulian.
*/
on date.julian2DMY  aJulian, at d, at m, at y
put aJulian + 68569.0 into l
put ( 4 * l  )  div  146097.0 into n
put l - ( 146097.0 * n + 3 )   div  4 into l
put ( 4000.0 * ( l + 1 ) )  div   1461001.0  into i -- (that's 1,461,001)
put l - ( 1461 * i  )  div  4 + 31 into l
put ( 80 * l )  div  2447.0  into j
put l - ( 2447.0 * j )  div  80 into d --  day
put j  div  11 into l
put j + 2 - ( 12 * l )  into m -- month
put 100 * ( n - 49 ) + i + l into y -- year
end  date.julian2DMY
 
Example:
date.julian2DMY 2452227,d,m,y
answer d,m,y


/H
 
Hugh Senior
The Flexible Learning Company
Web: _www.FlexibleLearning.com_ (http://www.flexiblelearning.com/) 
E: _h at flexiblelearning.com_ (mailto:h at flexiblelearning.com) 
T/F:  +44(0)1483.27 87 27