Re: [patch] ox-latex.el: Add `LATEX_PRE_HEADER' keyword

[Max Nikulin <manikulin@gmail.com>]

On 26/09/2023 04:57, Thomas S. Dye wrote:
> Aloha all,
> 
> Juan Manuel Macías <maciaschain@posteo.net> writes:
>>
>>> If so, Org should have native support of \DocumentMetadata, not
>>> LATEX_PRE_HEADER or something similar.
>>
>> If it were the only case of code before \documentclass, I would agree.
>> But, as I have already said above, the diversity of use cases makes the
>> implementation of /ad hoc/ solutions unviable, in my opinion.
> 
> FWIW, I agree with Juan Manuel here and would welcome a straightforward 
> way to insert material before the header.

I just have checked that a dirty hack with a few lines of code for 
`org-export-filter-final-output-functions' allows to insert arbitrary 
text to the beginning of export result. Perhaps a more elegant solution 
exists, but I admit it is not a straightforward way. At least it is 
possible.

I do not mind that generation of preamble should be more flexible, but I 
consider LATEX_PRE_HEADER as an ad hoc solution, so I am trying to find 
a better variant. That is why I asked for details concerning particular 
use cases.

I remember recipes like "put \usepackage{cmap} immediately after 
\documentclass" (nowadays this particular one should not be necessary). 
So I would prefer to avoid keywords per each chunk of preamble code.

\begin{filecontents*} from the original post is not convincing. 
\DocumentMetadata perhaps should be supported out of the box.

I would consider some kind of templates that use predefined fragments

#+LATEX_REPLACE_TEMPLATE: :preamble mypreamble
#+name: mypreamble
#+begin_src latex :exports none :noweb yes
\providecommand{\pdfxopts}{x-1a}
<<ox-latex-template-preamble>>
#+end_src

with ability to use fine grain snippets instead

#+LATEX_REPLACE_TEMPLATE: :preamble detailedpreamble
#+name: detailedpreamble
#+begin_src latex :exports none :noweb yes
<<ox-latex-template-DocumentMetadata>>
\PassOptionsToPackage...
<<ox-latex-template-documentclass>>
\usepackage{cmap}
\usepackage[english,<<ox-template-language>>]{babel}
<<ox-latex-template-usepackage>>
#+end_src


I hope, something similar may be made more readable than series of 
LATEX_HEADER & Co lines.