Verbatim R code with empty lang produces invalid {. .cell-code}

[zeileis]

Description

Problem: If I set up a quarto document with an R code cell with the lang option set to an emtpy string "", then this produces an invalid class specification for this code cell: {. .code-cell}.

Reproducible example: For a file verbatim.qmd containing

---
title: "Verbatim R code with empty lang"
format: html
---

```{r}
#| lang: ""
23
```

rendering via

quarto render verbatim.qmd --debug

yields verbatim.html (and also verbatim.html.md) with the class specification {. .cell-code} which is invalid.

Suggestion: It would be great if in this case the empty language would be omitted and only {.cell-code} were used.

Background: Of course, you can argue that I shouldn't set an empty language. However, this is a workaround I use in my exams package to be able to render the same verbatim R code more easily in both LaTeX and HTML via pandoc. The workaround was suggested by Yihui in this discussion on StackOverflow: https://stackoverflow.com/questions/72243968/plain-code-chunks-for-r-input-in-knitr-output

[cderv]

Thanks this look like a bug in our option handling. I'll fix it.

• Verbatim R code with empty lang produces invalid {. .cell-code} #13656

[zeileis]

Thanks, Christophe, very much appreciated!