How to undo reversed changes after a while in insert mode?

Question

I'm moving from Emacs to Neovim and still like a few things in Emacs functionality.

One of the things I find I would like is to stay in insert mode when I'm typing large documents (instead of constantly going back and forth).

One of the things I have remapped is:

inoremap <C-/> <C-\><C-o>:u<cr>

which reverses everything one by one when C-/ is pressed.

However, I want to only have this go on for a second unless there has been a C-/ pressed in that time interval, otherwise I want to undo the (undone) change that I have made. Is there a way to do this?

Thanks!

Answer 1

Here is an attempt of mapping:

function! InsertUndo()
  let t = reltimefloat(reltime())
  if exists('g:lastundo') && (t - g:lastundo) < 1
    let ret = "\<C-\>\<C-o>\<C-r>"
  else
    let ret = "\<C-\>\<C-o>u"
  endif
  let g:lastundo = t
  return ret
endfunction

inoremap <expr> <C-/> InsertUndo()

It undo the last change if no undo have been attempt in the last second otherwise it redo the last undone change.

Remark: That being said the general recommendation of Vim experts is to leave the insert mode often and do most of the operations in normal mode. But Vim is very configurable and you can create your own usage far away from Vim "philosophy" (although it is not recommended).