(add-to-list 'org-omit-holidays "1 Jan")

(add-to-list 'org-omit-holidays "1 May")

etc.

Then we could change (adapt) the

function calendar-check-holydays from holidays.el

I did a search-replace to something like this:

(defun org-check-calendar-omit-holidays (date)

"Check the list of org-omit-holidays for any that occur on DATE.

The value returned is a list of strings of relevant org-omit-holiday descriptions.

The org-omit-holidays are those in the list `org-omit-holidays'."

(let ((displayed-month (extract-calendar-month date))

(displayed-year (extract-calendar-year date))

(org-omit-holiday-list))

(dolist (h (calendar-org-omit-holiday-list))

(if (calendar-date-equal date (car h))

(setq org-omit-holiday-list (append org-omit-holiday-list (cdr h)))))

org-omit-holiday-list))

with these adaptation we could use a slighly changed version of the "diary-schedule" function I sent before.

I did not go further nor tested it.

Thinking again now: I think it is better to avoid holidays than week numbers. The problem is that we have to decide which holidays are "really" holidays and not rely on the holidays variables that come with Emacs.

Daniel

2009/12/28 Carsten Dominik <carsten.dominik@gmail.com>

Hi Daniel,

On Dec 27, 2009, at 1:51 AM, Daniel Martins wrote:

I liked the idea of org-diary-class!

I have added the function now to org-agenda.el

About avoiding holidays and certain weeks:

I used remind and wyrd for a while and they are a quite good software
for dealing with such appts.

There we have the OMIT function where we determine holidays and other
non-working days including Sat and Sundays

Normally we have an OMIT list at the beginning of file

Some functions simply omit those dates

Other expressions use another keyword AFTER (or BEFORE) to change
OMIT behaviour

like
23 Mar AFTER OMIT "Bank payment"

eg If 23 Mar is in Saturday it will appear in Monday

This preamble is just to say 2 things:

1) remind/wyrd could be used as a benchmark for some of the calendar
isuues we have

2) I do not know if the week number in a year is a practical way of
setting exceptions to org-diary-class

Daniel

PS Wyrd page is

http://pessimization.com/software/wyrd/

Interesting. But too complex for now - and I actually do prefer local control.

- Carsten

2009/12/26 Carsten Dominik <carsten.dominik@gmail.com>:

Hi Daniel,

I think it is a good idea to add such a function to org-mode. But I
am not sure if skipping holidays is the best, because Universities
also have lecture-free weeks etc.

So I am more thinking about a function like this (untested)

(defun org-diary-class (m1 d1 y1 m2 d2 y2 dayname &rest skip-weeks)
"Entry applies if date is between dates on DAYNAME, but skips SKIP-WEEKS.
Order of the parameters is M1, D1, Y1, M2, D2, Y2 if
`european-calendar-style' is nil, and D1, M1, Y1, D2, M2, Y2 if
`european-calendar-style' is t. The weeks are ISO week numbers where
the item should not apply."
(let* ((date1 (calendar-absolute-from-gregorian
(if european-calendar-style
(list d1 m1 y1)
(list m1 d1 y1))))
(date2 (calendar-absolute-from-gregorian
(if european-calendar-style
(list d2 m2 y2)
(list m2 d2 y2))))
(d (calendar-absolute-from-gregorian date)))
(and
(<= date1 d)
(<= d date2)
(= (calendar-day-of-week date) dayname)
(or (not skip-weeks)
(progn
(require 'cal-iso)
(not (member (car (calendar-iso-from-absolute d)) skip-weeks))))
entry)))

What do you think?

- Carsten

On Dec 21, 2009, at 4:54 PM, Daniel Martins wrote:

In fact, it helps! Thanks

However a sentence like this:

+# a class that meets every Monday evening between February 16 and
April 20, 2009
** Class 7:00pm-9:00pm
<%%(and (= 1 (calendar-day-of-week date)) (diary-block 2 16 2009 4 20
2009))>

is not an example of simplicity and visibility for a quite common feature!

Maybe as a suggestion we could encapsulate such a huge expression in a
simpler org-mode function ?

Daniel

PS In

http://www.emacswiki.org/cgi-bin/wiki/DiaryMode#toc12

I found another suggestion which I do not know how to include in org-mode

------------------------------------
Schedule

If you want to write a schedule for school or university, you need to
define a block (it’s derived from diary-block) between two dates and a
weekday. The following function also recognizes holidays and won’t
send you to school on those days… :)

(defun diary-schedule (m1 d1 y1 m2 d2 y2 dayname)
"Entry applies if date is between dates on DAYNAME.
Order of the parameters is M1, D1, Y1, M2, D2, Y2 if
`european-calendar-style' is nil, and D1, M1, Y1, D2, M2, Y2 if
`european-calendar-style' is t. Entry does not apply on a history."
(let ((date1 (calendar-absolute-from-gregorian
(if european-calendar-style
(list d1 m1 y1)
(list m1 d1 y1))))
(date2 (calendar-absolute-from-gregorian
(if european-calendar-style
(list d2 m2 y2)
(list m2 d2 y2))))
(d (calendar-absolute-from-gregorian date)))
(if (and
(<= date1 d)
(<= d date2)
(= (calendar-day-of-week date) dayname)
(not (check-calendar-holidays date))
)
entry)))

Then: "&%%(diary-schedule 22 4 2003 1 8 2003 2) 18:00 History"

------------------------------------

2009/12/20 Matt Lundin <mdl@imapmail.org>:

Daniel Martins <danielemc@gmail.com> writes:

All academics here present (including of course Carsten) suffer from
the same problem, I think

*** Math classes
<2009-12-10 Thu 11:00-14:00 +1w>

will repeat forever and ever...

We need to create a schedule for a period.

The package "remind" (and its simple interface "wyrd") do this job
wonderfully but I do not know how to deal with this problem in Org
mode

The following FAQ should help:

http://orgmode.org/worg/org-faq.php#diary-sexp-in-org-files

- Matt

- Carsten