Automate breaking of history in insert mode

Question

I started to learn ViM one month ago, so I'm not a ViM expert.

My question is: if I make some changes in insert mode (let's say I type some text, then I delete the last two words and finally type some other words) and then I press <ESC> u the entire text I typed in Insert mode disappears. I know the existence of the <CTRL-G> u command, which breaks the undo history, but I find it annoying typing <CTRL-G> u every single time I delete something. Is there a way to automate the execution of that command every time I press a key (<SPACE>, <BS>, ...) in insert mode?

Thanks a lot.

Answer 1

You can define insert mode mappings for those keys by prepending <c-g>u:

:inoremap <space> <c-g>u<space>
:inoremap <bs>    <c-g>u<bs>
:inoremap <c-w>   <c-g>u<c-w>
" etc.

Answer 2

See :help ins-special-special, that section has some specific examples on using inoremap to trigger <C-G>u automatically for specific keystrokes such as backspace or newline.

An example for using CTRL-G u:

    :inoremap <C-H> <C-G>u<C-H>

This redefines the backspace key to start a new undo sequence. You can now undo the effect of the backspace key, without changing what you typed before that, with CTRL-O u. Another example:

    :inoremap <CR> <C-]><C-G>u<CR>

This breaks undo at each line break. It also expands abbreviations before this.