[FR] Option to reference a _bookdown.yml file instead of having to place it in the root directory of the Rmd file

[PatrickRWright]

I am using bookdown extensively in project work. That is, I have directories containing a multitude of Reports that all have homogeneous styling that is sourced from a shared src directory via the Rmd YAML header. (e.g. a style.css via css:, some javascript via in_header: and a footer.html via after_body:). The benefit of this is that I do not have to copy the same files everywhere because I can just source them.

With _bookdown.yml, however, this kind of sourcing via the YAML header does not seem to be an option. i.e. I need to place the same _bookdown.yml in every directory where I am rendering one of my reports. I would much prefer being able to specify a cental _bookdown.yml source and the YAML header seems like the obvious place to do this.

As a current workaround I am using file.copy(from = "../../../src/_bookdown.yml", to = ".", overwrite = TRUE) in the Rmd setup chunk to copy the _bookdown.yml from my src directory to the root of my current Rmd build. It works, but it seems less tidy than it could be.

This is a cross reference explicitly pointing out why I need to use _bookdown.yml in my setup: https://stackoverflow.com/questions/79726280/how-can-i-make-the-figure-xx-text-bold-and-the-description-text-regular-font

[yihui]

Thanks for the request! I'm not sure if you know the function bookdown::render_book() has a config_file argument, so you can do

bookdown::render_book(config_file = "../../../src/_bookdown.yml")

Would that work for you?

[PatrickRWright]

Thanks for the tip I wasn't aware of that possibility.

Unfortunately, we have a lot of non-techy users who do the writing in Rmd files based on pre-prepared code chunks. These people completely lean on the RStudio GUI and thus the "Knit" button within. Thus, to me personally, as a technical user, that would work but in the larger scope, which is what is most important to me, it probably falls short.

[yihui]

Understood. Are you looking for something like a setting in the YAML header of index.Rmd?

[PatrickRWright]

We don't use it as index.Rmd specifically, but use bookdown::html_document2 to control a "regular" Rmd. I think we're talking about the same thing though, so I'll tentatively say "yes".

Here's an example of how I imagine this could look in the centext of our setup:

title: "Title"
subtitle: "Subtitle"
draft: false
output:
  bookdown::html_document2:
    bookdownsettings: "../../../src/_bookdown.yml" # <- here
    css: "../../../src/style.css"
    toc: true
    toc_depth: 3
    toc_float: true
    number_sections: false
    fig_caption: true
    includes:
      in_header: "../../../src/javascript.html"
      after_body: "../../../src/footer.html"
link-citations: yes
csl: "../../../bib/nature.csl"
bibliography: "../../../bib/references.bib"

[yihui]

I looked into this again and realized that we already had a function in {bookdown} that allows you to point to a custom config file, although the function is not exported at the moment. You can do

```{r, setup, include = FALSE}
bookdown:::load_config("../../../src/_bookdown.yml")
```

If this works for you and you want us to export/document this function, we can certainly do it.

[PatrickRWright]

Sorry, somehow I must have missed your answer. That looks great. I'll give it a spin and get back to you. Thanks!