kableExtra tables not processing markdown

[debruine]

Bug description

Tables with markdown or html have to have escape = FALSE to not show the markdown or html verbatim when displaying in a table with kable().

• If you you display the table with knitr::kable(), both types of links display correctly as links
• If you use kableExtra::kable(), the markdown version just shows the markdown verbatim
• However, if you unclass() the result of the kableExtra version, it does display markdown links correctly
• The reprex below shows these problems in a .qmd file, but not if knit in an .Rmd file

Reprex of the problem:

---
title: "kableExtra Escape Reprex"
format: html
---

Create table with markdown and html links:

```{r}
tbl <- data.frame(
  markdown = "[github](https://github.com)",
  html = "<a href='https://github.com'>github</a>"
)

Both work with knitr::kable()

knitr::kable(tbl, escape = FALSE) 

The markdown version doesn't work with kableExtra::kable()

kableExtra::kable(tbl, escape = FALSE) 

But if you unclass() and cat() the result, it does work:

kableExtra::kable(tbl, escape = FALSE) |>
  unclass() |> cat()

<img width="828" alt="kableExtra-quarto" src="https://user-images.githubusercontent.com/14863295/183250174-150280f1-7c43-4d60-887f-5bd8ac6c338c.png">

### `quarto check` Output

FYI: for RStudio users who aren't familiar with the command line, you might want to instruct them to paste the output of `quarto::quarto_path() |> paste("check") |> system()`.

```bash
[✓] Checking Quarto installation......OK
      Version: 1.0.36
      Path: /Applications/RStudio.app/Contents/MacOS/quarto/bin

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.7.3
      Path: /Applications/Xcode.app/Contents/Developer/usr/bin/python3
      Jupyter: (None)

      Jupyter is not available in this Python installation.
      Install with python3 -m pip install jupyter

[✓] Checking R installation...........OK
      Version: 4.2.0
      Path: /Library/Frameworks/R.framework/Resources
      LibPaths:
        - /Library/Frameworks/R.framework/Versions/4.2/Resources/library
      rmarkdown: 2.14

[✓] Checking Knitr engine render......OK

I'm running RStudio 2022.07.1 Build 554 "Spotted Wakerobin" Release (7872775e, 2022-07-22) for macOS Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) QtWebEngine/5.12.10 Chrome/69.0.3497.128 Safari/537.36

quarto tools check Output

[✓] Inspecting tools

Tool         Status                    Installed     Latest  
chromium     Not installed             ---           869685  
tinytex      External Installation     ---           v2022.08

Checklist

• [X] formatted your issue so it is easier for us to read?
• [X] included a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
• [X] documented the quarto version you're running, by pasting the output from running quarto check in the "Quarto Check Output" text area?
• [X] documented the version of the quarto tools you're running, by providing the output from running quarto tools check in the "Quarto Tools Check Output" text area?
• [X] documented the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
• [X] documented which operating system you're running? If on Linux, please provide the specific distribution as well.
• [X] upgraded to the latest version, including your versions of R, the RStudio IDE, and relevant R packages?

[norcalbiostat]

Thank you for adding this clear example. I have been trying for a few weeks to find the right place to get an answer to this problem.

[jjallaire]

The kableExtra package might require some updates to detect when its running in pandoc and emit the requisite raw markdown or HTML