How to reference metadata from _quarto.yml in a Quarto extension _extension.yml?

[fredguth]

MWE in github

Inside my extension, I want _quarto.yml to hide it is using a book project type under the hood.

Ideally, I would have in my _quarto.yml:

project:
  type: tmp
tmp:
  tmp_title: "My Title"

I need to reference $tmp.tmp_title$ inside _extensions/tmp/_extension.yml:

title: tmp
author: Fred
version: 0.1.0
contributes:
  project:
    project:
      type: book
      output-dir: docs
    tmp:
      tmp_title: "title"
    book:
      title: ${tmp.tmp_title}
      author: "Jane Doe"
      date: "1/16/2023"
      chapters:
        - index.qmd
        - intro.qmd
        - summary.qmd
        - references.qmd

I tried to do it like I do inside any partials tex file, but it does not work in the .yml file. How do I do that?

[dragonstyle]

You should be able to use the meta shortcode:

quarto.yml:

project:
  type: tmp
tmp:
  tmp_title: "My Title"
bibliography: references.bib

extension.yml:

title: tmp
author: Fred
version: 0.1.0
contributes:
  project:
    project:
      type: book
      output-dir: docs
    book:
      title: "{{< meta tmp.tmp_title >}}"
      author: "Jane Doe"
      date: "1/16/2023"
      chapters:
        - index.qmd
        - intro.qmd
        - summary.qmd
        - references.qmd
  formats:
    html:
      theme: cosmo
    pdf:
      documentclass: scrreprt


  # formats:
  #   pdf:
  #     template: monashthesis.tex

Would that work?

[fredguth]

Note:
❯ quarto --version
1.2.313

[dragonstyle]

Ahh, I hadn't anticipated that (the file name). We resolve shortcodes like meta for the contents of documents, but they are not always resolved early enough in the process for all the various places they're used (outside of contents) to get the correct resolved value.

[fredguth]

Maybe I could write a lua filter that changes the name afterwards?
Would that work?

How can I change the filename as a last step?

[dragonstyle]

You'd have to change the filename using a post render script, I think (just rename the file I think). The output filename is determined before we resolve the shortcodes, so it will be used 'as is' (as you noticed).

[fredguth]

Hmmm, I have never done that....
I just read the documentation.
I understand that I could add to my _extension.yml something like:

title: tmp
author: Fred
version: 0.2.0
contributes:
  project:
    project:
      type: book
      output-dir: docs
      post-render: rename.py
    tmp:
      tmp_title: "title"
    book:
      title: "{{< meta tmp.tmp_title >}}"
...

But how do rename.py access tmp.tmp_title or book.title? I see there is a way to access the files, will I have to parse the yaml files again in python? Would it be easier in typescript?