Insert variables in the document metadata (top YAML section)

[e-alizadeh]

I've created a blog using Quarto. If possible, I'd like to use variables in the document metadata. In particular, in order to standardize the name of categories, I want to use variables defined somewhere else like in _variables.yml file and then call it in a post metadata.
Going through the Variables page, it seems that it's not possible since Quarto treats that section differently. So, I thought of asking here if there is a way to use variables in the document metadata?

If not, then I can create a feature request!

[mcanouil]

I am not sure to understand what you try/want to achieve, could you provide an example, even if those are not working as expected?

[e-alizadeh]

Sorry. Here is an example.

Let's say I have the following _variables.yml file next to _quarto.yml:

kws:
  - k1: keyword1
  - k2: keyword2
  - k3: keyword3

And I want to read those variables in the markdown's meta section as below:

---
title: "title"
categories: [{{ <var kws.k1 >}}, {{ <var kws.k2 >}}]
abc: def
---

# Header 1

Reading {{ <var kws.k1 >}} works!

[mcanouil]

The issue is that you are using an array to define the keywords and to call the var shortcode.

See the code

• Quarto document:

  ---
  title: "title"
  categories:
    - "{{< var kws.k1 >}}"
    - "{{< var kws.k2 >}}"
  abc: def
  ---
  
  # Header 1
  
  Reading {{< var kws.k1 >}} works!
  

• _variables.yml

  kws:
    k1: keyword1
    k2: keyword2
    k3: keyword3
  

[e-alizadeh]

Thanks @mcanouil . Your code works. Thanks for the help.

[nithinmkp]

can you explain this a little bit? i did not understand how quarto is understanding kws.k1 is coming from _variables.yml

[mcanouil]

That's the var shortcode, see the documentation.

I suggest you navigate through the documentation instead of reviving two years old thread.

[wiesehahn]

Is there also a way to insert paths?

E.g. in _variables.yml I define

favicon: /images/favicon.png

and add it in _quarto.yml with

website:
    favicon: "{{< var favicon >}}"

it reads the path as path_to_project/_site/{{< var favicon >}}'

[mcanouil]

@wiesehahn I opened an issue to allow markdown parsing:

• website.favicon key is not parsed as markdown (possibly other keys) #6455

[Beforerr]

Is it possible to insert dict-like variables? For example I want to insert an author across mulitple documents.

• _variables.yml

authors:
  abc:
     name: ABC 
     email: [email protected]
     orcid: 0000-0000

• in document

---
title: "title"
authors:
  - "{{< var authors.abc >}}"
---

[mcanouil]

Did you try it?
Note that you still need to provide the correct schema for authors.

[Beforerr]

I tried it and it did not work

[mcanouil]

Then you have your answer.

Why not use _quarto.yml, _metadata.yml, and/or YAML frontmatter for this?
And possibly Quarto profiles?

And or metadata-files key to provide an _authors.yml or whatever.

[Beforerr]

The reason for not using _quarto.yml, _metadata.yml is that I need it in some documents but not all documents.
Also nothing appear if I use variables in the main body of a document.

Reading "{{< var authors.abc >}}" does not work:)

[mcanouil]

Then use a global default one and override on a per document basis.