Including LaTeX macros from a file within a custom format

[allefeld]

Description

I am trying to define a custom format document-html which automatically includes a list of LaTeX macros from a file math-definitions.tex. These macros are simple substitutions (e.g. \newcommand{\rk}{\operatorname{rank}}) and should be processed by Pandoc, not by MathJax or another math rendering solution.

In another discussion (#2845) the result was that the best way to include macros for Pandoc processing was to use an include shortcode,

{{< include math-definitions.tex >}}

If I include the file in my custom format, the correct shortcode would be

{{< include _extensions/document/math-definitions.tex >}}

However, I have not been able to figure out how to configure my custom format to include this snippet of text at the beginning of the Markdown source before it is being processed by Quarto (so that the shortcode actually works)?

---

As an alternative, previously in pure Pandoc I defined a format using a defaults file including the line input-file: math-definitions.tex. I tried to do the same in the document/_extension.yml file for my custom format:

contributes:
  formats:
    html:
      input-file: math-definitions.tex

When I process a Quarto document using this custom format, Quarto says

pandoc 
  to: html
…  

metadata
…
  input-file: _extensions/document/math-definitions.tex
…

Which suggests that the option from my document/_extension.yml was modified to include the path to the _extensions subfolder and passed to Pandoc. However, If I use one of the defined macros in an equation in the document, it doesn't work.

What am I doing wrong? Is there a way to achieve what I want?

[allefeld]

Figured it out.

Apparently, input-file: is not passed on to Pandoc by Quarto, but defaults: is. I can therefore in my custom format definition write

contributes:
  formats:
    html:
      defaults: math-definitions.yaml

and include in the format a file math-definitions.yaml which contains

input-file: _extensions/document/math-definitions.tex

[allefeld]

I haven't checked whether that works with qmd files in subdirectories in a project though.

[allefeld]

I'm guessing

input-file: ${.}/math-definitions.tex

should work in projects.

[dhodge180]

Did you work out a way to include comments in your math-definitions.tex file?

I find that comments provided using the % comment symbol get displayed in the text at the top (I'm compiling a website).

[allefeld]

No, I don't have any comments in my math-definitions.tex file. The file is treated as Pandoc input, not as LaTeX input, therefore I guess you could use HTML comments supported by Pandoc: <!-- -->.