Including LaTeX macros from a file into a quarto book

[baptiste]

Maybe I've missed something in the docs, but I can't find a clear way to include an entire file of LaTeX macros. Say I have a file _macros.tex full of \newcommand macros as I'm writing a book involving lots of equations, what's the best way to make those macros known to pandoc+mathjax when it's rendering the content (either to html or pdf)?

What I currently have is this in my _quarto.yml:

  html:
    include-in-header:
       - "_dollar.tex"
       - "_macros.tex"
       - "_dollar.tex"
  pdf:
    include-in-header:
       - "_macros.tex"

where _dollar.tex is a dummy file containing $$. This seems to work, but the dummy $$s isn't very elegant. Have I missed some way to include both files and raw text in the header?

EDIT: No, actually, this works for the chapters where I do use maths, but for the others I get the raw content dumped above the page.

The alternative seems to be inserting the macros into each qmd file as follows:

::: {.content-hidden}
$$
{{< include _macros.tex >}}
$$
:::

which suits Mathjax. For LaTeX, the macros are still fed (once) via include-in-header, and the {.content-hidden} includes are not written in the tex file, so this seems to work.

[baptiste]

Just a thought, maybe a pre-processor that would run something like de-macro would be a more robust way to go?

[baptiste]

Another possible route might be to configure Mathjax such that it knows about the macros, but that doesn't seem trivial (one would need to convert the _macros.tex file into this format and inject it in the right place when Mathjax is set up by (pandoc? quarto?)).

[vsheg]

Same thoughts. I guess a new parameter in _quarto.qmd would be very useful:

# _quarto.yaml
...
macros: _macros.tex # import a list of TeX/LaTeX definitions
...

% macros.tex
\def\bb{\mathbb}
\def\bf{\mathbf}
\def\cl{\mathcal}

---

Or more general mechanism with an initialization file _init.qmd (and an according option init: _init.qmd) which automatically runs before any of *.qmd:

# _init.qmd
::: {.content-hidden}
$ {{< include _macros.tex >}} $
:::

[mcanouil]

LaTeX macros are only LaTeX code/text, thus include-in-header, include-before-body, and/or include-after-body can be used to include raw LaTeX.
Note that Pandoc can actually deal with most raw LaTeX code.

MathJax is an independent Javascript library. Quarto is not tied to it, MathJax is only a default value. KaTeX and several other libraries can also be used with their own particular syntax and configuration. I don't think Quarto should even try to make assumptions on configuring those libraries.
Also, there are several Discussions here about configuring MathJax for different use cases, which all involves the use of include-in-header, include-before-body, and/or include-after-body.

Finally your issue, your post lack a minimal reproducible example to really help.
If you can post a small minimal example exhibiting the issue you initially described, someone here could help.
The issue could for instance be a syntax issue in one of your files, an issue with Quarto, an issue with Pandoc, etc.

[cderv]

@baptiste following discussion at

• Defining custom macros is not possible with Katex #7518 (comment)

did you try directly

{{< include _macros.tex >}}

Without the $$ before and fater.

Pandoc's seems to do Macros expansion for HTML based on raw LaTeX block contents, so this would probably work to have your Macros expanded.

[mcaruel]

There is an easy solution to that problem of multiply defined latex command when rendering pdf document. At the beginning of every .md or .qmd files where potentially duplicate command are defined, for html output, just add this

::: {.content-visible unless-format="pdf"}
{{< include PATH_TO/macros.tex >}}
:::

The file macros.tex contains the commands (without line comments starting with a %. I found that solution while trying to avoid the inclusion of video content when rendering in pdf format.

[mcanouil]

For HTML/MathJax, there is the .hidden class alsso: https://quarto.org/docs/authoring/markdown-basics.html#equations

[mcaruel]

I know but this methods generates lots of duplicate commands warning when rendering in pdf.

[mcanouil]

Maybe, but you can still use it with conditional content which is safer than injecting raw latex.

[allefeld]

Another solution to the duplicate commands warning would be to use \providecommand instead of \newcommand, possibly in combination with \renewcommand. See What do newcommand, renewcommand, and providecommand do, and how do they differ?.