Is it possible to setup vim to use vimtex for Rmd files?

Question

I need to write Rmd files, but I can't imagine life without vimtex. Is there a way that I can use vimtex with Rmd files? Ideally, I would also like to keep the syntax highlighting that I have for Rmd files (via https://github.com/vim-pandoc/vim-rmarkdown).

Edit: In response to a comment by @filbranden, here is useful post that provides more information on Rmarkdown. Because the files are rendered using pandoc, one can mix R code with standard markdown with LaTeX.

As a simple example, an Rmarkdown file might contain code that looks like this:

# My document header
Here is an **emphasis**. Now here's some LaTeX:

\begin{align}
    \hat{\beta} = \hat{\alpha}^{3} + \epsilon.
\end{align}

In a .tex document I could use vimtex features, such as cse inside the align environment to toggle it to an align* environment. That's just one of many many features of vimtex that I would like to be able to use in Rmd.

@Karl Yngve Lervåg is the creator of vimtex, so if he doesn't know of a solution then that's not a great sign for there being one...

Is it a bad idea to "trick" vim into thinking that an Rmd is a Tex file? Then presumably I could use vimtex features? The downside is that the syntax highlighting would be messed up.

Answer 1

After a lot of trial and error, I found a reasonable solution. I expect this is not a "good" solution, so would appreciate any thoughts as to how it could go wrong, and how to strengthen it.

To get vimtex features to load, I simply put this in ftplugin/rmd.vim:

set filetype=tex

That's it --- now all of the vimtex bindings and motions appear to load when I open an rmd.vim file. Many of the vimtex features obviously won't work correctly with .rmd files, such as the ones that involve compiling and expect a .tex document. However, the NVim-R plugin provides good compilation/viewing solutions for .rmd, and I am still able to use that after set filetype=tex, presumably because they have already been loaded.

A major source of confusion for me was that there is a difference in syntax highlighting behavior between calling :set filetype=tex manually after opening a file, and putting set filetype=tex in ftplugin/rmd.vim. Changing the filetype manually also changes the syntax highlighting, but changing the filetype inside the ftplugin script preserves the .rmd syntax highlighting. I think this is because scripts in syntax are called after those in ftplugin, but I'm not sure.

The upshot is that if you put the filetype call into ftplugin, you can both load vimtex features and preserve rmd syntax highlighting --- which is what I wanted.