Nvim external commands to write and delete files inside a function

Question

I use Neovim in a Linux (Arch Linux) environment. I have written a function to help me preview my markdown documents in PDF format without using a whole plugin. I've also added a simple command named "Prev" to call this function.

Here's the relevant part of my vimrc file :

function! s:pdf_preview()
    ! pandoc % -s -f markdown -t odt -o ~/.cache/%:t:r.odt > ~/.cache/%:t:r_Prev_log.txt 2>&1
    ! soffice --headless --convert-to pdf --outdir ~/.cache ~/.cache/%:t:r.odt >> ~/.cache/%:t:r_Prev_log.txt 2>&1
    ! zathura ~/.cache/%:t:r.pdf >> ~/.cache/%:t:r_Prev_log.txt 2>&1
endfunction
command Prev call s:pdf_preview()

Note : I'm using soffice to convert from odt to pdf to avoid installing a LaTeX processor (which I think would be required by pandoc for a direct conversion from markdown to pdf).

I'd like to improve this function in two ways :

1. save the current file in the .cache folder before the "! pandoc" command, so that I can use this temporary file for the preview instead of having to save my document each time ;
2. delete the temporary files (the odt and the pdf files) once the preview with zathura is closed.

Thanx for any help !

Answer 1

You can use :write {filename} to save your file in a different location without changing the active buffer.

Regarding your second question, you could look at :help job-control which describes how to start asynchronous process in Neovim. The on_exit callback may be what you need. For example the following snippet prints a message after then seconds

function! Echo(job_id, data, event)
    echo "CLOSED!"
endfunction

call jobstart (
    \ [
    \ 'bash',
    \ '-c',
    \ 'for i in {1..10}; do echo hello $i!; sleep 1; done'],
    \ {'on_exit': 'Echo'})

So, jobstart takes two arguments, the first is a list with the command to execute, and the second is a dictionary that maps events to functions. You only care about exiting Zathura, that's why the example only includes the on_exit event. You could try to write a function mapped to the on_exit event that deletes the file when called, and a script executed by jobstart that launches Zathura and returns the control to Neovim when it is closed