Warn on empty location list

[goodboy]

I was using this plug I found some time ago until finding your lovely alternative:

function! toggle#GetBufferList()
  redir =>buflist
  silent! ls
  redir END
  return buflist
endfunction

function! toggle#ToggleList(bufname, pfx)
  let buflist = toggle#GetBufferList()
  for bufnum in map(filter(split(buflist, '\n'), 'v:val =~ "'.a:bufname.'"'), 'str2nr(matchstr(v:val, "\\d\\+"))')
    if bufwinnr(bufnum) != -1
      exec(a:pfx.'close')
      return
    endif
  endfor
  if a:pfx == 'l' && len(getloclist(0)) == 0
    echohl ErrorMsg
    echo "Location List is Empty."
    return
  endif
  let winnr = winnr()
  exec(a:pfx.'open')
  if winnr() != winnr
    wincmd p
  endif
endfunction

The thing I miss is the error message that alerts you that the list is empty.
Not sure if you'd be cool with adding something like that or not?

@tgoodlet You can check my fork ListToggle.vim. I added this error handling and I'm using the <Plug> special key. This allows for lazy loading in a plugin manager like vim-plug or dein.
Example:

Plug 'fszymanski/ListToggle.vim', {
      \ 'on': ['<Plug>ListToggleQuickfixListToggle',
      \        '<Plug>ListToggleLocationListToggle']
      \ }

let g:listtoggle_no_maps = 1

nmap <Leader>q <Plug>ListToggleQuickfixListToggle
nmap <Leader>l <Plug>ListToggleLocationListToggle