Include parameters in header and footer in Quarto PDF?

[jhelvy]

I asked this question on SO as well. Is it possible to include parameters in the header and / or footer text of a Quarto PDF document?

This issue shows how to include general text in the header and footer, but I want to include a parameter in the header or footer that I can pass while rendering.

In the example below, the parameter name can be rendered in the main body, but I do not know if it is possible to include it in the header.

---
title: "Untitled"
format:
  pdf:
    include-in-header:
      text: |
        \usepackage{scrlayer-scrpage}
        \rohead{Header text}
        \lofoot{Footer text}
params:
  name: "John"
---

# Chapter ONE

My name is `r params$name`

\newpage

# Chapter TWO

[cscheid]

(EDITED: I just realized our meta shortcode works on YAML itself.)

Use a shortcode: {{< meta params.name >}}

[jhelvy]

That's what I was afraid of :(
Hopefully someone can find a hack to implement this.

[cscheid]

Actually it just occurred to me that the meta shortcode should work. You can't run arbitrary code but you can grab information from the yaml metadata. I've tested this on HTML, but that should work in general:

---
title: "Untitled"
format:
  html:
    include-in-header:
      text: |
        <meta name="key" content="{{< meta params.name >}}"/>
params:
  name: foo
---

{{< meta params.name >}}

I then see this in the HTML header:

[baptiste]

For latex, you can use this workaround: have the header/footer refer to a macro, that you define later on in the document

---
title: "Untitled"
format:
  pdf:
    keep-tex: true
    include-in-header:
      text: |
        \usepackage{scrlayer-scrpage}
        \rohead{\myname}
params:
  name: "John"

engine: knitr
---

# Chapter ONE

My name is `r params$name`

\newcommand{\myname}{`r params$name`}


\newpage

# Chapter TWO

[cscheid]

That's clever!

[jhelvy]

I've been trying to come up with something like this - beautiful!

[cscheid]

@jhelvy There may be a native solution for the simple case of resolving a parameter, but @baptiste's trick is going to be more general, because it lets you refer to anything that's evaluated.