Include linked headings when exporting to PDF

Question

Given a test.org file like

* A level one heading
** [[file:other.org*some_heading][Some good stuffs]]

If I export it to HTML, Some good stuffs can get a nice link to another HTML. But this is not the case when exporting to PDF.

So when exporting to PDF, I want to include the actual content of some_heading. I know I can use something like

#+INCLUDE: "other.org*some_heading"

But that's a comment, and it's not easy for me to see the origin structure of test.org. I want it at least look like a heading in the org file.

Is there a way to keep Some good stuffs a link when exporting to HTML while include its actual content when exporting to PDF? Thanks.

Answer 1

I finally come up with this solution, if you have better solution please post your answers!

(defun org-count-skip-lines-before-heading (filename)
  (with-temp-buffer
    (insert-file-contents-literally filename)
    (goto-char (point-min))
    (let ((count 0))
      (while (and (< (line-end-position) (point-max))
                  (not (string-match "^[ ]*\\*+" (thing-at-point 'line))))
        (incf count)
        (forward-line))
      (if (>= (line-end-position) (point-max))
          (incf count))
      count)))

(defvar-local org-export-to-latex-follow-heading-link t)
(defun org-export-to-latex-include-linked-headings (backend)
  (when (and (org-export-derived-backend-p backend 'latex)
             org-export-to-latex-follow-heading-link)
    (org-map-entries
     (lambda ()
       ;; If current heading has no content.
       (unless (org-element-property :contents-begin (org-element-at-point))
         (let ((text (nth 4 (org-heading-components))))
           ;; If current heading is a org link.
           (if (string-match org-bracket-link-regexp text)
               (let ((location (match-string 1 text))
                     (description (match-string 2 text)))
                 (when (string-prefix-p "file" location)
                   ;; Remove link protocol.
                   (setq location (replace-regexp-in-string "^[a-zA-Z]+:" "" location))
                   ;; Skip property lines if including a whole file.
                   (let ((line-spec (if (string-match ".+::\\*+.+" location)
                                        ""
                                      (format ":lines \"%d-\"" (org-count-skip-lines-before-heading location)))))
                     (forward-line)
                     (insert (format "#+include: \"%s\" %s :only-contents t" location line-spec)))
                   (write-file "shit.org"))))))))))
(add-hook 'org-export-before-processing-hook  #'org-export-to-latex-include-linked-headings)

This will have the effect that a linked heading with empty contents to a local file in any level will be exported using its actual content when exporting to latex/PDF.

Set org-export-to-latex-follow-heading-link to nil in buffers that you don't want this behavior!