R code in LaTeX in YAML before_body include

Question

I have a LaTeX section that I put at the top of my knitr generated PDF document. I achieved this by using the YAML options

output:
    pdf_document: 
        includes: 
            before_body: file.tex

file.tex contains code like this

\textsf{Reporting: `r 2+2`}

but this doesn't work. Is there another way that I can get this value? Passing in a parameter is fine if that's possible.

Thanks!

Answer 1

You have to knit file.tex. I suggest you rename file.tex, e.g., to file.Rnw, and in your main R Markdown document:

```{r, include=FALSE}
writeLines(knitr::knit_child('file.Rnw'), 'file.tex')
```