Per-file variables via frontmatter key variables

[rben01]

Description

Currently, Quarto files can include variables in one of two ways: {{< var foo >}} with a project-wide _variables.yml, or {{< meta bar >}} from the file’s metadata. It would be great to have file-local variables with a variables key in the frontmatter that could be used like {{< meta variables.baz >}} (or perhaps a shorthand like {{< filevar baz >}}).

[mcanouil]

If you set the variables in the frontmatter, it means those are metadata so you can use the metadata shortcode to retrieve them.

If you want to have a "variables" key, then I suggest to write a Lua filter/shortcode for this purpose.

I don't think there is something to be done in Quarto here, but I might have missed the purpose of your request and in which way Quarto does not achieve that currently.

[mcanouil]

Anything but "params" (which comes from knitr not Quarto) in the frontmatter is metadata. That's how it is and it's very unlikely going to change.
As I said, now if you want to add some specific definition such as "variables" in addition to be a metadata (you can't change that) is a "variable" you'll have to make that yourself.
Making something like that inside Quarto will only create confusion as what are variables and what are metadata.
Feel free to create your own metadata organisational convention such as:

---
my-variables:
  my-first-variable: whatever
---

{{< meta my-variables.my-first-variable >}}

Or create a Lua filter/shortcode named "filevar" which will basically read the metadata and read only "variables".

---
my-variables:
  my-first-variable: whatever
---

{{< filevar my-first-variable >}}

or

{{< meta my-variables.my-first-variable >}}

See https://github.com/mcanouil/quarto-lua-env which adds metadata from the Lua environment which can then be accessed using the following two approaches:

{{< lua-env quarto.doc.input_file >}}

{{< meta lua-env.quarto.doc.input_file >}}

[rben01]

I tried your first option, but it didn't work, which is why I opened this issue.

WARNING (/Applications/quarto/share/filters/main.lua:15686) Unknown meta key variables.my-first-variable specified in a metadata Shortcode.

The result in the output is ?meta:variables.my-first-variable.

[mcanouil]

It appears variables is used internally to provide "Pandoc metadata variables" so you cannot use it.

[rben01]

Oh, lol. I opened this discussion precisely because I tried to use variables as the grouping key and it didn't work. Switching to vars does indeed work. Thanks!

Should this behavior be documented somewhere?

[mcanouil]

Rather than documentation, I believe the best option is YAML validation to warn users.