Re: finding a parent node

[l.stelmach@samsung.com (Łukasz Stelmach)]

It was <2013-07-02 wto 13:06>, when Thorsten Jolitz wrote:
> l.stelmach@samsung.com (Łukasz Stelmach) writes:
>
> Hello Lukasz, 
>
> assume my simple-test.org with a :TASK: tag:
>
> #+begin_src org
> * header 1
>   :PROPERTIES:
>   :CUSTOM_ID: XYZ22
>   :END:
> * header 2                             :TASK:
>   [2013-06-28 Fr 11:01]
> ** subheader 1
> Some text
> ** subheader 2
>
> More text and a table
>
> | label  | col1 | col2 |
> |--------+------+------|
> | string | 3    | 4    |
>
> Text and a src-block
>
> #+begin_src emacs-lisp 
>  (+ 3 4)
> #+end_src
>
> #+end_src
>
>> With my point somewher deep I'like to find the closest parent heading
>> tagged :TASKS:.
>
> Lets move point to the source-block and get `org-element-context':
>
> #+begin_src emacs-lisp
> (with-current-buffer
>     (find-file
>      "/path/to/simple-test.org")
>     (goto-char (point-min))
>     (org-babel-next-src-block)
>     (message "%s" (point))
>      (format "%s"
>      (org-element-context)))
> #+end_src
> #+begin_quote
> "(src-block (:language emacs-lisp :switches nil :parameters nil :begin 319
>  :end 362 :number-lines nil :preserve-indent nil :retain-labels t :use-labels
>  t :label-fmt nil :hiddenp nil :value (+ 3 4) :post-blank 0 :post-affiliated
>  319 :parent nil))"
> #+end_quote
>
> too bad, does not work in isolated use, :parent is nil. Othewise one could
> get the parent(s) and check for the :TASK: tag. 
>
> So the only way to find this headline I know of would be:
>
> #+begin_src emacs-lisp
> (with-current-buffer
>   (find-file-noselect
>      "/path/to/simple-test.org")
>   (let ((tree (org-element-parse-buffer)))
>   (org-element-map tree 'headline
>    (lambda (hl)
>      (and
>       (member "TASK" (org-element-property :tags hl))
>       (list (org-element-property :begin hl)
>             (org-element-property :end hl)))))))
> #+end_src
>
> returns
>
> ,-----------
> | ((55 362))
> `-----------
>
> so you could at least find out if (point) is inside a headline with a :TASK:
> tag, then get this headline and use its attribute list to move to some place
> inside of it. 
>
> But I'm sure Nicolas can give you a much better solution (I would be
> interested in that solution too). 

This might be enough for me as I get the tree in the exporting
code.  However, this way is far from efficient. If only there was a way
to find the current element in the tree.

I am not sure yet, but a sequence of org-back-to-heading  and
re-search-backward inside a save-excursion may be the easiest way to
place the point where I want it.

Any other thoughts?
-- 
Łukasz Stelmach
Samsung R&D Institute Poland
Samsung Electronics