Re: [O] accessing properties in org-element-parse-buffer tree

[Eike]

Thanks a lot for the examples, they are very helpful! I first thought to
parse the org buffer and then work with the resulting tree. But your
examples now makes me think to work directly on the buffer. Well, I will
play with a few different ways now…

Regards
Eike


Thorsten Jolitz writes:

> Eike <address@hidden> writes:
>
> Hello,
>
>> I want to ask for help regarding elisp and org-elements. I like to
>> access the properties of all my headlines and I created the following
>> function (tree is the parsed tree) that collects them into an a-list:
>>
>> #+begin_src emacs-lisp
>>   (defun collect-props (tree)
>>     (car (org-element-map tree 'headline
>>            (lambda (hl)
>>              (when (eq 2 (org-element-property :level hl)) ; want only 
>> level-2 properties
>>                (org-element-map hl 'node-property
>>                  (lambda (np)
>>                    (cons (org-element-property :key np)
>>                          (org-element-property :value np)))))))))
>> #+end_src
>>
>> I'm not very confident about this, is this ok? Is there a better way?
>> For example, the first car looks strange, and I don't know how to get
>> rid of it.
>
> * Answer
>   :PROPERTIES:
>   :CUSTOM_ID: abc123
>   :foo:      bar
>   :END:
>
> There are several options, here a few examples, some using my new
> function 'org-dp-filter-node-props' from org-dp-lib.el which is very
> good at filtering out only those node-properties you are really
> interested in. 'org-entry-properties' does some filtering too, but its
> less generic.
>
> #+NAME: ex1
> #+BEGIN_SRC emacs-lisp :results raw
> (org-map-entries
> (lambda () (org-entry-properties nil nil "foo")))
> #+END_SRC
>
> #+results:
> (((CATEGORY . 989)) ((CUSTOM_ID . abc123) (foo . bar) (CATEGORY . 989)))
>
> #+NAME: ex2
> #+BEGIN_SRC emacs-lisp :results raw
> (require 'org-dp-lib)
> (org-map-entries
>   (lambda () (org-dp-filter-node-props 'org t t)))
> #+END_SRC
>
> #+results:
> (nil ((foo . bar)))
>
> #+NAME: ex3
> #+BEGIN_SRC emacs-lisp :results raw
>   (org-element-map (org-element-parse-buffer 'headline) 'headline
>     (lambda (hl)
>       (when (eq 1 (org-element-property :level hl)) ; want only level-2 
> properties
>       (org-element-property :FOO hl))))
> #+END_SRC
>
> #+results: ex3
> (bar)
>
> #+NAME: ex4
> #+BEGIN_SRC emacs-lisp :results raw
>   (let (props)
>     (save-excursion
>       (goto-char (point-min))
>       (while (re-search-forward "^\\*+ " nil t)
>         (save-excursion
>           (beginning-of-line)
>           (setq props
>                 (cons
>                  (org-dp-filter-node-props
>                   '("FOO" "CUSTOM_ID") nil t)
>                  props))))
>       (delq nil props)))
> #+END_SRC
>
> #+results: ex4
> (((foo . bar) (CUSTOM_ID . abc123)))
>
>
> PS 1
>
> Strange behaviour in src-block ex1.
>
> Neither the example given nor
>
> (org-entry-properties nil "foo")
> (org-entry-properties nil "foo" "foo")
>
> return what I would expect.
>
> PS 2
>
> Without the :results header-arg I get the following error when running
> src-block ex2:
>
> Debugger entered--Lisp error: (args-out-of-range 0 1)
>   orgtbl-to-orgtbl((nil (("foo" . "bar"))) (:fmt (lambda (cell) (format "%s" 
> cell))))
>   org-babel-insert-result((nil (("foo" . "bar"))) ("replace") ("emacs-lisp" 
> "(require 'org-dp-lib)\n(org-map-entries (lambda () (org-dp-filter-node-props 
> 'org t t)))" ((:comments . "") (:shebang . "") (:cache . "no") (:padline . 
> "") (:noweb . "no") (:tangle . "no") (:exports . "code") (:results . 
> "replace") (:session . "none") (:hlines . "no") (:result-type . value) 
> (:result-params "replace") (:rowname-names) (:colname-names)) "" nil 0 
> #<marker at 1263 in *outorg-edit-buffer*>) nil 0 "emacs-lisp")
>   org-babel-execute-src-block(nil)
>   org-babel-execute-src-block-maybe()
>   org-babel-execute-maybe()
>   org-babel-execute-safely-maybe()
>   run-hook-with-args-until-success(org-babel-execute-safely-maybe)
>   org-ctrl-c-ctrl-c(nil)
>   call-interactively(org-ctrl-c-ctrl-c nil nil)