Re: Question about string-match and match-string

[Rasmus]

Julien Cubizolles <j.cubizolles@free.fr> writes:

> Rasmus <rasmus@gmx.us> writes:
>
>> (with-eval-after-load 'ox
>>   (defun rasmus/org-latex-ignore-heading (headline backend info)
>>     "Strip headline from HEADLINE if it has tag ignoreheading for
>>       certain headlines.  `info' is ignored"
>>     (when (and (org-export-derived-backend-p backend 'latex 'html 'ascii 
>> 'odt)
>>             (string-match "\\`.*ignoreheading.*\n"
>>                           (downcase headline)))
>>       (replace-match "" nil nil headline)))  
>>
>>   (add-to-list 'org-export-filter-headline-functions
>>             'rasmus/org-latex-ignore-heading))
>
> It's working, thanks, but it's ignored if you use tags:nil option (which
> is pretty common I guess). 

Well. . .  If you never want tags perhaps the correct way is to never
have tag export e.g. via a filter or a derived backend. 

> If however you use
>
> #+TITLE: Titre
> #+OPTIONS: tags:nil
>
> * First Heading                                                         :tag:
> blablabla
> * Second Heading                                              :ignoreheading:
> blablabla
>
> Both the first and second heading are displayed (not what I want).

Try this then. . .  It's ugly.  Also, you can't easily do this with
html due to divs and tab of contents, manually numbering etc.  So
you'd need a derived backend.  I don't know about odt. 

It's an ugly hack.

  (defun rasmus/org-latex-ignore-heading (headline backend info)
    "Strip headline from HEADLINE if it has tag ignoreheading."
    (let* ((tags (org-element-property :tags
                                       (plist-get 
                                        (text-properties-at
                                         (- (string-match "\n" headline) 2) 
headline)
                                        :parent))))
      (when (and (member-ignore-case "ignoreheading" tags)
                 (org-export-derived-backend-p backend 'latex 'ascii))
        (string-match "\\`.*\n.*\n" headline)
        (replace-match "" nil nil headline))))

Alternatively, you can add hook removing lines before parsing which
would give nice results in all backend, but then this won't work:

* h1 :noexport:
* h2 :ignoreheading:
my protected section

If you never have such constructions this is a better solution.

(defun rasmus/remove-ignored-headlines-before-parse (backend)
  "Remove headlines with tag \"ignoreheading\" before parsing"
  (dolist (x 
           (org-element-map (org-element-parse-buffer 'headlines)
               'headline (lambda (h) (cons (org-element-property :tags h)
                                           (org-element-property :begin h)))))
    (save-excursion (when (member-ignore-case "ignoreheading" (car x))
                      (goto-char (cdr x)) (delete-region 
(line-beginning-position) (line-end-position))))))
(add-hook 'org-export-before-parsing-hook 
'rasmus/remove-ignored-headlines-before-parse)


> Finally, something weird with the title: if you don't define it with de
> #+TITLE, it's set to name_of_thefile$_{\text{ignoreheading}}$...

I can't reproduce.

–Rasmus

-- 
A page of history is worth a volume of logic