Allow 'opfunc' to be local.

[ubaldot]

Sometimes I am in need of using different 'opfunc' for different buffers.

For example, I would need a 'opfunc' for text filetype, another one for python filetypes and so on.
It would be handy to make this option local.

[zeertzjq]

Usually 'opfunc' is only set temporarily, so there is no need for local 'opfunc' values. What is the use case of setting 'opfunc' permanently?

[ubaldot]

I have exactly this use-case:

In ~/.vim/autoload/utils.vim:

def UndoFormatting()
  if v:shell_error != 0
    undo
    echoerr $"'{&l:formatprg->matchstr('^\s*\S*')}' returned errors."
  else
    # Display format command
    redraw
    if !empty(&l:formatprg)
      echo $'{&l:formatprg}'
    else
      echo "'formatprg' is empty. Using default formatter."
    endif
  endif
enddef

export def FormatWithoutMoving(type: string = '')
  # 'gq' is remapped to use this function.
  # However, when running 'gq', we need to use as it is
  # shipped with Vim, and therefore we use the bang in 'normal!', below
  var view = winsaveview()

  # defer so if the function gets error of any kind, the following are run
  # anyways
  defer UndoFormatting()
  defer winrestview(view)

  var start = 0
  var end = 0
  if type != ''
    start = line("'[")
    end = line("']")
  endif

  if start == 0 && end == 0
    normal! gggqG
  else
    var interval = end - start + 1
    silent exe $"normal! {start}gg{interval}gqq"
  endif
enddef

in ~/.vim/ftplugin/markdown.vim:

import autoload '../autoload/mde_utils.vim' as utils

# ...

def SetMarkdownOpFunc()
  &l:opfunc = function('utils.FormatWithoutMoving')
enddef

# Hack on 'gq'
nnoremap <buffer> <silent> gq <ScriptCmd>SetMarkdownOpFunc()<cr>g@
xnoremap <buffer> <silent> gq <ScriptCmd>SetMarkdownOpFunc()<cr>g@

When I am editing a markdown file, I get what I expect when I use gq.
When I switch to a e.g. text-filetype file, then the gq mappings are
reset, but 'opfunc' stays set to function('utils.FormatWithoutMoving') , i.e. it is not reset.

EDIT: a workaround could be to save/restore the previous value of 'opfunc' in some way, but I have the feeling to end up in a non-so-nice hack. It would be better to have it as local option IMHO.

[Konfekt]

Do you maybe only want to keep the cursor position when operating on the whole buffer? If no formatprg/expr is set, then gw is gq keeping the cursor

[chrisbra]

but 'opfunc' stays set to function('utils.FormatWithoutMoving') , i.e. it is not reset.

And you are unsetting 'opfunc' inside b:undo_ftplugin?

[ubaldot]

Auch!