I have a setting (namely highlight the 81st character on the line) that I would like to turn off when there is a diff. This is easy enough as a search through the autocmds results in:
|FilterWritePre| starting to write a file for a filter command or diff
|FilterWritePost| after writing a file for a filter command or diff
So I end up with:
" Highlight the 81st character on the line if it's not the quickfix.
autocmd BufReadPost * if (&filetype != 'qf') |
\ let b:ColorColumnID = matchadd('ColorColumn', '\%81v.') |
\ endif
" When diffing take out the coloring because it looks like diff highlighting.
autocmd FilterWritePost * if (&diff && exists('b:ColorColumnID')) |
\ call matchdelete(b:ColorColumnID) |
\ endif
However, I would also like to turn the setting back on when I leave diff mode. As far as I can tell, there's no autocmd to detect this, and I can't think of any other robust ways to do it. Obviously I could check &diff on every cursor move or something like that, but I'm hoping for something a little less hacky. Any ideas?
:setcommand, maybe you could try to use theOptionSetevent. With this event, the pattern is matched again the full name of an option, and Vim should populate the internal variablesv:option_oldandv:option_newwith the old and new values of the option. Maybe something like this would be a start:autocmd OptionSet diff if v:option_new ==# 'diff' | {disable custom highlighting} | else | {enable custom highlighting} | endif.matchadd()is local to the window, not to the buffer, so maybew:would be better thanb:for the scope of theColorColumnIDvariable.