Can't get autocmd function to ignore certain buffer types. Help?

Lua
1

Hey all!

I just took the neovim pill a few weeks ago, and now I can’t seem to get enough. Longtime vim user, and I am blown away at all the new functionality of neovim and the new plugins. Thanks so much to everyone!

I’m trying to convert a Trailing White Space vimscript I had in my old .vimrc. I think I got the conversion done, but now when I bring up certain plugins (togglerterm in floating mode, alpha, Telescope), the trailing whitespace is run, and it makes it look ugly. I’d like to ignore certain buffer types, and I can’t seem to make it work. Looking for any help.

Herere is the original vimscript:

augroup WhitespaceMatch    
  " Remove ALL autocommands for the WhitespaceMatch group.    
  autocmd!    
  autocmd BufWinEnter * let w:whitespace_match_number =    
        \ matchadd('ExtraWhitespace', '\s\+$')    
  autocmd InsertEnter * call s:ToggleWhitespaceMatch('i')    
  autocmd InsertLeave * call s:ToggleWhitespaceMatch('n')    
augroup END 
   
function! s:ToggleWhitespaceMatch(mode)    
  let pattern = (a:mode == 'i') ? '\s\+\%#\@<!$' : '\s\+$'    
  if exists('w:whitespace_match_number')    
    call matchdelete(w:whitespace_match_number)    
    call matchadd('ExtraWhitespace', pattern, 10, w:whitespace_match_number)    
  else    
    " Something went wrong, try to be graceful.    
    let w:whitespace_match_number =  matchadd('ExtraWhitespace', pattern)    
  endif    
endfunction

highlight ExtraWhitespace ctermbg=red guibg=red

And here is what I converted it to. I am commenting on the lines that don’t seem to work, instead of adding them in later. I do believe I have reached parity with the old script, but I can’t figure out how to ignore certain buffer types.

vim.cmd([[highlight ExtraWhitespace ctermbg=red guibg=red]])

local autocmd = vim.api.nvim_create_autocmd
local augroup = vim.api.nvim_create_augroup

local whtSpcGrp = augroup("ExtraWhiteSpace", { clear = true})

local excluded_buffertypes = {"toggleterm", "alpha", 'TelescopePrompt', 'Trouble', 'help', 'TelescopeResults'}

autocmd("BufWinEnter", {
  callback = function()
 
    -- my attempt to return early and not act on buffer type.
    if vim.tbl_contains(excluded_buffertypes, vim.bo.filetype) then
      return
    end

    vim.w.whitespace_match_number = vim.fn.matchadd('ExtraWhitespace', [[\s\+$]])
  end,
  group = whtSpcGrp,
})


autocmd("InsertEnter", {
  callback = function()
    ToggleWhitespaceMatch('i')
  end,
  group = whtSpcGrp,
})

autocmd("InsertLeave", {
  callback = function()
    ToggleWhitespaceMatch('n')
  end,
  group = whtSpcGrp,
})


function _G.ToggleWhitespaceMatch(mode)

  -- my attempt to return early and not act on buffer type.
  if vim.tbl_contains(excluded_buffertypes, vim.bo.filetype) then
    return
  end

  local pattern = ""
  if mode == "i" then
    pattern = [[\s\+\%#\@<!$]]
  else
    pattern = [[\s\+$]]
  end

  if vim.fn.exists(vim.w.whitespace_match_number) then
    vim.fn.matchdelete(vim.w.whitespace_match_number)
    vim.fn.matchadd('ExtraWhiteSpace', pattern, 10, vim.w.whitespace_match_number)
  else
    vim.w.whitespace_match_number = vim.fn.matchadd('ExtraWhiteSpace', pattern)
  end
end

When I run this, it works as I would expect in my normal files. However, when I run toggleterm, or alpha, it finds the whitespaces and highlights them. I’d really prefer it doesn’t.

I know there are other Trailing Whitespace plugins I could use, and I’m open to them, but converting this vimscript to lua was incredible practice in learning lua, neovim lua scripting, and neovim. I just got stuck on this.

Thanks for any advice.

2

Instead of using autocommand(s), why not try to apply filetype specific highlightings? For example, if you work with Python often, you could add this line to the ftplugin/python.vim file in the runtimepath:

highlight ExtraWhitespace ctermbg=red guibg=red

If you prefer Lua syntax instead, add the following line to the ftplugin/python.lua instead:

vim.api.nvim_set_hl.highlight(
    0, "ExtraWhitespace", { guibg = red, ctermbg = red }
)