Using variables and meta in _quarto.yml

[royfrancis]

Description

I understand that variables defined in _variables.yml can be used in any qmd file using {{< var bla >}}.

I have two questions. One is if a variable defined in _variables.yml can be used in _quarto.yml?

Second question is if yaml variables defined in _quarto.yml can be reused in the same document without using _variables.yml? Here is a made up example:

_quarto.yml

project:
  type: website
  output-dir: "bla"

website:
  page-footer:
    border: false
    left: "The output dir is {{< var project.output-dir >}}"

I've tried both and they don't seem to work.

quarto --version
1.5.56

[mcanouil]

_quarto.yml does not include "variables", it's metadata.
To access them you need meta shortcode.
Not to be confused with var and _variables.yml.

And from my testing it works.

• _quarto.yml

  title: "{{< var my-title >}}"

• _variables.yml

  my-title: "My Title"

• index.qmd

  ---
  format: html
  ---
  
  This is a playground for Quarto.
  
  {{< lipsum 1 >}}
  
  ![An image]({{< placeholder 600 400 >}}){#fig-placeholder}

[mcanouil]

You can even do weirder things (sorry only a screenshot for this one):

[royfrancis]

Good point about meta. I had forgotten about it.

Anyway, I tried your example with a small change.

_quarto.yml

project:
  output-dir: "{{< var output-dir >}}"

_variables.yml

output-dir: bla

index.qmd

---
format: html
---

Testing

Running quarto render in this directory produces an output directory named {{< var output-dir >}}. I was expecting the output dir to be named bla.

And for my other question, I used meta as you suggested.

_quarto.yml

random: "bla"
project:
  output-dir: "{{< meta random >}}"

index.qmd

---
format: html
---

Testing

This creates an output directory named {{< meta random >}}. I was expecting the output dir to be named bla.

[mcanouil]

output-dir is not a text field and is not parsed.
If you want different output-dir, then the approach is with profiles not variables, especially in a context of website/book project.

[cscheid]

You're running into an unfortunate part of Quarto, which we should improve on, but will take a long time to fix properly.

The fundamental issue is that parts of the metadata are handled in Typescript, and parts of the metadata are handled in Lua. For the parts that are handled in Typescript, you can't use shortcodes, since those are resolved in Lua.

Your next question is likely going to be "ok, but which is which?", and I don't have a great answer to give you here. output-dir is certainly handled in Typescript, but we don't have an enumeration of this in the docs.