Filippo A. Salustri <salustri@ryerson.ca> wrote:The basic idea in all of these situations is to use org-map-entries
> Hi all,
> I'm looking for a little coding help.
>
> I want to try to a task's priority automatically, based on the priorities of its subtasks.
> Specifically, I'd like to set the priority of the task to the priority of the highest-priority
> subtask.
> And I'd like that task priority to be updated (if necessary) automatically any time I change the
> priority of one of its subtasks.
>
from the mapping API:
(info "(org) Using the mapping API")
to walk the entries, applying a function on each.
The function to apply on each entry is frequently a specialization
of one of the functions provided by the property API:
(info "(org) Using the property API")
In this case, you need a function to get the priority of each entry:
(def fas/task-priority ()
(org-entry-get (point) "PRIORITY"))
which you can then give to org-map-entries:
(org-map-entries (function fas/task-priority) t 'tree)
The assumption here is that we are at the head node and we have
an arbitrary number of subnodes. The call above will accumulate
the priorities of each subnode in a list (if a subnode does not
have a priority assigned, the priority will be nil).
For example, applying
* section
** [#B] subsection
*** [#C] subsubsection
**** paragraph
***** [#B] subparagraph
will return the list
(nil "B" "C" nil "B")
It is then just a matter of finding the highest priority and applying
it to the top node. Assuming that "A" is higher priority than "B" etc,
something like this will do:
--8<---------------cut here---------------start------------->8---
(defun fas/task-priority ()
(org-entry-get (point) "PRIORITY"))
(defun fas/set-task-priority ()
(interactive)
(let* ((priorities (org-map-entries (function fas/task-priority) t 'tree))
(sortedpriorities (sort (delq nil priorities) (function string-lessp))))
(if sortedpriorities
(org-priority (aref (car sortedpriorities) 0)))))
--8<---------------cut here---------------end--------------->8---
org-priority wants a character, but sortedpriorities is a list of
strings, hence the aref rigmarole. It should work even if *no*
priorities are set at all: sortedpriorities will be nil, so nothing will
be done.
Nick