2022-01-19: With the release of VimTeX v2.8, all the hack here may not be needed anymore.

Since --remote option hasn’t been restored by Neovim, it is actually not very straightforward to set up inverse search for PDF files when we are editing large LaTeX files with the help of VimTeX.

I spend some time figuring out how to do it on both Windows and macOS and succeed. I thought it would be helpful for people looking for the solution.

First step#

Although Neovim removed the --remote option, it has a complete RPC api by which a client can talk to it and controls its behavior. When Neovim starts, it always starts a server¹. The neovim-remote project utilizes the RPC api of neovim to mimic the --remote behavior and its friends. First, we need to install this package:

pip install neovim-remote

It comes with an executable named nvr. To connect to a running Neovim instance and run a command, we can use the following command:

nvr --servername server_address -c "echo 'hello'"

Option --servername specifies a valid Neovim server address (i.e., the value v:servername). Option -c means to run a command in the specified Neovim instance.

Second step#

Each time we start a new neovim instance, the server address changes. It is cumbersome to copy this address when we want to communicate with this Neovim instance. We can write the server address to a temporary file and read the server address from that file when running the nvr command.

Add the following setting to nvim config:

function! s:write_server_name() abort
  let nvim_server_file = (has('win32') ? $TEMP : '/tmp') . '/vimtexserver.txt'
  call writefile([v:servername], nvim_server_file)
endfunction

augroup vimtex_common
  autocmd!
  autocmd FileType tex call s:write_server_name()
augroup END

When we open a LaTeX source file, the server name will be written to vimtexserver.txt so that we can later read it easily.

Third step#

Now we need to set up the corresponding PDF viewer to do inverse search. The setup differs based on your system and PDF viewer.

Skim on macOS#

Open Skim PDF viewer, open the Preferences menu (shortcut: Command+,) and go to Sync page. Set up the section PDF-Tex Sync support, use the following settings:

• Preset: Custom
• Command: nvr
• Arguments: --servername `cat /tmp/vimtexserver.txt` +"%line" "%file"

To start inverse search, press Shift and Command, then click the text you want to inv-search.

Sumatra PDF on Windows#

Open Sumatra PDF, go to Settings --> Options, in the bottom part, there is a section Set inverse search command-line, put the following command there:

cmd /c for /F %i in ('type C:\Users\ADMINI~1\AppData\Local\Temp\vimtexserver.txt') do nvr --servername %i -c "normal! zzzv" +"%l" "%f"

The meaning of %f and %l:

• %f: tex source file path corresponding to current pdf.
• %l: line in the original tex file.

I know the above command is complicated and looks super weird, but it’s the only way that works out of the numerous other ways I have tried. Note that cmd /c is needed, without which, Sumatra PDF will complain that the inverse search command is wrong:

Can not start inverse search command. Please check the command line in the settings.

Double click somewhere in the PDF file, your cursor in nvim/nvim-qt should go to the corresponding line in the file buffer.

I have also posted this setup on VimTeX repo, check this issue.

Conclusion#

In this post, I give a summary on how to set up inverse search for Neovim on different platforms. After all these setup, inverse search should work out of the box without any manual labor.

References#

• echo the content of a file to command line on Windows
  • https://superuser.com/q/162713/736190
  • https://superuser.com/q/256651/736190
• Batch/cmd equivalent of Bash backtick
  • https://stackoverflow.com/q/2768608/6064933
  • https://superuser.com/q/289344/736190