Date manangement.

Date manangement.

[Timothy Hobbs]

Hello.  This is Timothy.

Is there a good way to add on day to a date of any sort?  time-date.el doesn't
seem to be good at this.  What I need to do is add a day, incramenting months,
and years, correctly, so 2008/03/31+1 = 2008/04/00 not 2008/03/32...

I am currently working on a bit of elisp for planner which imports ical files.
So I need to be able to import events that span multiple days, as mutliple tasks.
This requires walking through the days creating a task for each one covered.

Timothy

Re: Date manangement.

[Thierry Volpiatto]

Timothy Hobbs <tim.thelion@gmail.com> writes:

> Hello.  This is Timothy.
>
> Is there a good way to add on day to a date of any sort?  time-date.el doesn't
> seem to be good at this.  What I need to do is add a day, incramenting months,
> and years, correctly, so 2008/03/31+1 = 2008/04/00 not 2008/03/32...
>
> I am currently working on a bit of elisp for planner which imports ical files.
> So I need to be able to import events that span multiple days, as mutliple tasks.
> This requires walking through the days creating a task for each one covered.
>
> Timothy
>
>
>

Hello, may be we meet us on planner mailing-list, i sent you there 
some code doing what you want, there is a function incrementing date, 
you can easily modify it for your need. here is the function:

,----
| (defun tv-time-date-in-n-days (days)
|   "Return the date in string form in n +/-days"
|   (let* ((days-in-sec (* 3600 (* (+ days) 24)))
| 	 (interval-days-sec (if `(< ,days 0)
| 				(+ (float-time (current-time)) days-in-sec)
| 			      (- (float-time (current-time)) days-in-sec)))
| 	 (sec-to-time (seconds-to-time interval-days-sec))
| 	 (time-dec (decode-time sec-to-time))
| 	 (new-date ""))
|     (setq new-date (concat
| 		    (int-to-string (nth 5 time-dec))
| 		    "."
| 		    (substring (int-to-string (/ (float (nth 4 time-dec)) 100)) 2)
| 		    "."
| 		    (substring (int-to-string (/ (float (nth 3 time-dec)) 100)) 2)))
|     new-date))
`----

,----
| ELISP> (tv-time-date-in-n-days -12)
| "2008.03.13"
| ELISP> (tv-time-date-in-n-days 32)
| "2008.04.26"
`----


-- 
A + Thierry
Pub key: http://pgp.mit.edu

Re: Date manangement.

[Dmitri Minaev]

On Tue, Mar 25, 2008 at 1:25 AM, Timothy Hobbs <tim.thelion@gmail.com> wrote:
>  Is there a good way to add on day to a date of any sort?  time-date.el doesn't
>  seem to be good at this.  What I need to do is add a day, incramenting months,
>  and years, correctly, so 2008/03/31+1 = 2008/04/00 not 2008/03/32...

Use Calc, either as a separate application (M-x calc), or in embedded
mode (see more in  `info calc`, or from your own lisp code:

(calc-eval "<21 jan 2008> +110")
"<Sat May 10, 2008>"


-- 
With best regards,
Dmitri Minaev

Russian history blog: http://minaev.blogspot.com

Re: Date manangement.

[Giles Chamberlin]

Timothy Hobbs <tim.thelion@gmail.com> writes:

>
> Is there a good way to add on day to a date of any sort?  time-date.el doesn't
> seem to be good at this.  What I need to do is add a day, incramenting months,
> and years, correctly, so 2008/03/31+1 = 2008/04/00 not 2008/03/32...

Have a look at calendar-absolute-from-gregorian which returns an
integer rep of the date which you can then do arithmetic with.
-- 
Giles