org-latex-export: Name sections according to CUSTOM_ID rather than headline (%s)?

Question

Problem description

In org-mode's LaTeX export configuration, the %s operator can be used as a placeholder for the headline string, as can be seen in the examples at

https://orgmode.org/worg/org-tutorials/org-latex-export.html

For reasons far too complicated to explain here, I would like to name the sections in my exported .tex file not according to the corresponding headlines in my .org file, but instead according to the respective sections' CUSTOM_ID property.

I am wondering whether it is possible to achieve this. For example, there might be an operator equivalent to %s, which is automatically replaced by a section's CUSTOM_ID rather than by its headline?

Example to illustrate

I'd like the .org code

* My section
:PROPERTIES:
:CUSTOM_ID: foo
:END:

to result in the following .tex code when exported via C-c C-e C-b l L:

\section{foo}

and not in the following:

\section{My section}

Answer 1

Why can't you name the section "foo" in the first place?

In any case, the transcoding of a headline into the appropriate latex construct is done by org-latex-headline in ox-latex.el. The headline is transcoded by calling the function specified by the :latex-format-headline-function which by default is org-latex-format-headline-default-function. You can customize the setting of the option to your own function and model that on the default function. The main difficulty will be getting the custom_id out of the info parameter (I hope that the custom_id is in the info parameter, but I have not checked: ymmv).

Not a complete answer, but I hope it is illuminating enough for you to be able to see where to go from here.

Answer 2

You can do this with an org-export-before-parsing-hook. The functions in this hook can be used to modify a copy of the org-buffer prior to exporting it. I would let-bind this variable in a special :noexport: heading in your document like this:

* build                                                            :noexport:

#+BEGIN_SRC emacs-lisp
(let ((org-export-before-parsing-hook
       '(lambda (_)
      (org-element-map (org-element-parse-buffer)
          'headline
        (lambda (hl)
          (when (org-element-property :CUSTOM_ID hl)
            (goto-char (org-element-property :begin hl))
            (org-edit-headline (org-element-property :CUSTOM_ID hl))))))))
  (org-latex-export-to-latex))
#+END_SRC

Then, you just run this block, e.g. by C-c C-c to create the tex-file. You can modify the last line if you want to also make the pdf and open it.