A More Betterer Autosave In Vim

Run :version in your local Vim. What do you see?

Here are the first two lines I get:

:version
VIM - Vi IMproved 7.4 (2013 Aug 10, compiled Feb 24 2015 14:04:47)

That 7.4 is the key thing.

I actually wrote in old time (December 2013, as I recall; this was on an older site) about a cool new(-ish) autocommand event, or rather a pair of events, which someone sent a patch to the vim_dev list about—they were not mentioned in the help file. I don’t know when the events were added, but in Vim 7.4, the help file situation was remedied, and now we have this as the help for TextChanged and TextChangedI:

                                                        TextChanged
TextChanged            After a change was made to the text in the
                       current buffer in Normal mode.  That is when
                       b:changedtick has changed.
                       Not triggered when there is typeahead or when
                       an operator is pending.
                       Careful: This is triggered very often, don't
                       do anything that the user does not expect or
                       that is slow.
                                                        TextChangedI
TextChangedI           After a change was made to the text in the
                       current buffer in Insert mode.
                       Not triggered when the popup menu is visible.
                       Otherwise the same as TextChanged.


I’ve (since writing that) upgraded to OS X Yosemite, and was back on its system Vim until today, in fact. (Its system Vim is a 7.3.) So I’d forgotten about these events, and was not even using an auto-saving trick for some time (until my last post, as it turns out). Then “Unknown” reminded me of the events (albeit indirectly) with a comment on that last post, “Save time in Vim NOW with these five weird tricks”, which mentioned an auto-saving autocommand as a bonus (sixth) trick:

Sadly auto-save a file when you leave insert mode doesn't do anything for edits made in normal mode (dd to delete a line etc)

(And yes, as you can see, I just upgraded to 7.4 again today. Yay Homebrew!)

I hereby, therefore, give you a new and improved (or at least improved) autocommand, Unknown! Here it is:

autocmd InsertLeave,TextChanged * if expand('%') != '' | update | endif

As the help text says, TextChanged watches for changes to the text (hmm—what a surprise!) when we’re in normal mode, which is where we do things such as dd, p, c, etc.; InsertLeave only notices that we’ve left insert mode (and thus lets us save all of the changes we made there, which is very nice of it). So the combined effect of the two events in this improved autocommand should be to take care of All Your Autosaving Needs (TM).

The one thing to keep in mind with this version is that, well, it saves after basically every change to the buffer. This means that after every accidental command or mis-pasted text, Vim will write the file. You can always undo it right afterwards, of course, if you notice it, but still. (Plus, as the help implies, this will cause our file to be saved quite often—normally we would consider this a Win, but if you’re the kind of Vimmist that’s doing 382,000,000,000 editing operations a second, who knows.)

So, I’m going to go with something like at the end of a recipe when they say “Salt to taste.” Try it out, and maybe it’ll prove massively helpful. (I’m trying it out again now myself.) Or, your taste might run more toward the old InsertLeave one (or even to not using an autosave at all—I would not understand that point of view myself, but to own his each).