Use Quarto extensions for the {asar} report template

[Bai-Li-NOAA]

While working on the NSAP Quarto slides template demo this week, I ended up exploring Quarto extensions in more depth. They feel quite similar in spirit to R packages, but specifically tailored for Quarto. The more I read, the more I wondered whether the {asar} report template might be a good candidate for a Quarto extension rather than remaining purely an R package, while {stockplotr} would still be an excellent R package for content generation. For example, Quarto already supports extensions for journal articles (examples here: https://quarto.org/docs/extensions/listing-journals.html, GitHub org: https://github.com/quarto-journals). Below is a quick comparison of approaches from Gemini:

Feature	Using an R Package for Templating	Using a Quarto Extension for Templating
Primary Method	Generating template code (HTML/LaTeX) as strings inside R functions.	Declaring formatting rules in separate files (CSS, LaTeX, Lua).
Maintainability	Lower – logic and presentation get intertwined (“string soup”).	Higher – clean separation of content, structure, and presentation.
Portability	Limited – tied to R.	Excellent – works with any compute engine (R, Python, etc.).
Collaboration	Harder – everyone needs to be an R programmer.	Easier – designers, developers, and analysts can work on their respective files.
Best For	Special cases needing complex, dynamic R logic to build the template itself.	Most cases – standard, robust, and recommended method.

One thing that caught my attention is the approach of generating template code as strings inside R functions. If developers think that writing R functions that output long strings of Markdown or LaTeX is becoming difficult to read and maintain, a Quarto extension template might be a better fit. See a conceptual example from Gemini below. Instead of having a LaTeX title page template, you'd have an R function that generates the required LaTeX code as a character string.

# A conceptual example of an R function for templating
create_title_page <- function(title, author) {
  # This mixes R logic with LaTeX code, which can get messy
  latex_string <- paste0(
    "\\begin{titlepage}\n",
    "  \\centering\n",
    "  {\\Huge ", title, " \\par}\n",
    "  \\vspace{1cm}\n",
    "  {\\Large ", author, " \\par}\n",
    "\\end{titlepage}"
  )
  # In your Quarto doc, you'd call this in a code chunk with results='asis'
  cat(latex_string)
}

I haven’t developed any Quarto extensions myself, but I’ve recently noticed their growing presence and found that installing/adding a template to a project seems straightforward. Others (e.g., Jonathan Peake) who have experience with extension development, may have better insights on this topic.