Nicolas Goaziou <m...@nicolasgoaziou.fr> writes:
Hello,
> Thorsten Jolitz <tjol...@gmail.com> writes:
>
>> when programming with Org elements sometimes things seem to work and
>> then something strange happens - what smells like a cache problem. I
>> don't mean a cache bug, but a programmer (me) not taking the cache
>> into account the right way.
>
> It might also be a cache problem. Do not hesitate to report it.
Ok
>> Is there a short introduction somewhere about the 'todos' and 'nogos' in
>> programming with elements wrt to the org-element-cache?
>
> The only "nogo" is to never modify (destructively) a value returned by
> `org-element-at-point' or `org-element-context'. Consider their return
> value as read-only, and possibly invalid as soon as you modify the
> buffer.
This one directly applies to my use-case (wrt `org-element-at-point').
Is it ok to do these two things:
- let-bind a value returned by `org-element-at-point' and modify it (with
plist-put), and
1. then return the interpreted value or
2. do (delete-region ...) on old element and then insert the
(interpreted) new one?
- globally set a value returned by `org-element-at-point', modify it
(with plist-put) in a function call, but use the variable as a quoted
(!) function arg and reset the original value with this trick:
#+begin_src emacs-lisp
(setq X (org-element-at-point))
(defun foo (element &optional replace-p)
(let ((elem (eval element)))
[...destructively modify elem...]
[...interpret elem ...]
(when replace-p
[...delete old-element ...]
[...insert interpreted elem, goto beg ...]
(set element (org-element-at-point)))))
(foo 'X t)
#+end_src
> These advices don't apply to `org-element-parse-buffer', which doesn't
> use cache (if it did, it should copy cached elements beforehand anyway).
Ok
--
cheers,
Thorsten
