Rmarkdown beamer_presentation: "missing \item" LaTex error if an R chunk is included and-CodePudding

I want to use the LaTeX \ovalbox{} command from the fancybox package in an Rmarkdown beamer_presentation, knitted from within RStudio. However, as soon as I add a simple R chunk, I get an "! LaTeX Error: Something's wrong--perhaps a missing \item."

This is a minimum reproducible example:

---
output:
  beamer_presentation
header-includes: |
  \usepackage{fancybox}
---

## Slide 1

\ovalbox{an oval box}
```{r}
print("x")
```

I can hand-solve the problem afterwards in the .tex file by moving the \usepackage{fancybox} command before the \usepackage{fancyvrb} command which is automatically inserted during the knitting.

Any suggestions how to avoid this problem in the first place?

CodePudding user response：

Seems the packages are fighting over how to mess with verbatim environments.

Normally one could simply load them in a different order, but of course rmarkdown makes such a simple task a lot more complicate. You can make your document compile using this hack (don't try to use any of the verbatim commands from fancybox, this might explode...):

---
output:
  beamer_presentation
header-includes: |
  \let\VerbatimEnvironmentsave\VerbatimEnvironment
  \usepackage{fancybox}
  \let\VerbatimEnvironment\VerbatimEnvironmentsave
---

## Slide 1

\ovalbox{an oval box}
```{r}
print("x")
```