Modified undo behavior
From Vim Tips Wiki
created 2005 · complexity intermediate · author Nigeria · version 6.0
I was getting frustrated with the default undo behavior in Vim because sometimes one of my "changes" would be very long (many lines), and I would want to undo one line at a time. So I came up with the idea to change the behavior with the following code that can be inserted into your vimrc:
function! EnterStuff() let theLine = getline(line(".")) let pos = col("'^") execute "normal mqu\<C-r>`q" if(pos > len(theLine)) startinsert! else if(pos > 1) normal l endif startinsert endif endfunction function! ChangeUndoMode(theNum) if(a:theNum == 1) inoremap <C-w> <C-w>^O^[ inoremap <CR> <Esc>:call EnterStuff()<CR><CR> elseif(a:theNum == 2) inoremap <C-w> <C-w>^O^[ inoremap <BS> <BS>^O^[ inoremap <DEL> <DEL>^O^[ inoremap <CR> <Esc>:call EnterStuff()<CR><CR> else iunmap <C-w> iunmap <BS> iunmap <DEL> iunmap <CR> endif endfunction call ChangeUndoMode(1) nmap \sun :call ChangeUndoMode(1)<CR> nmap \gun :call ChangeUndoMode(2)<CR> nmap \bun :call ChangeUndoMode(3)<CR>
Be sure to write "^O^[" as two characters: ctrl-o and ESC.
So the above code works fairly well. <C-w>, <BS>, <DEL>, <CR> all add to the undo list. The <CR> one took me a long time to figure out. The way it is done in the above code is the only way I know that doesn't mess up indentation. ^O^[ automatically screws up indentation.
You can use <c-g>u to break the undo chain:
inoremap <BS> <c-g>u<BS> inoremap <CR> <c-g>u<CR> inoremap <del> <c-g>u<del> inoremap <c-w> <c-g>u<c-w>
should have the same effects.
One more thing you can do is hit <End> while typing a sentence to end the undo sequence. The only reason <C-g>u is needed in the above example is because it doesn't screw up auto-indentation. Normally though, hitting <End> is a great way to end the undo sequence.
My <End> does not break the undo chain. I had to explicitly imap it to do so:
inoremap <End> <C-g>u<End>
The <C-G>u trick seems not to be mentioned in gvim 6.1 docs and does not work either with this version.
Be careful: "<C-g>u<Space>" breaks abbreviations induced by a <Space>
Very odd. Try
:imap <Space> <Space><C-g>u
to make abbrevs work. Do not try
:imap <Space> <C-g>u<Space>
Vim will hang after using Space (use <C-c> to stop).