Re: Reliable after-change-functions (via: Using incremental parsing in Emacs)

[Eli Zaretskii]

> From: Stefan Monnier <address@hidden>
> Cc: Dmitry Gutov <address@hidden>,  address@hidden,  address@hidden,
>   address@hidden
> Date: Tue, 31 Mar 2020 13:16:33 -0400
> 
> > It should be obvious that sending a buffer as a single string is less
> > efficient than letting tree-sitter access buffer text directly.  We
> > just need an appropriate API for that (maybe there is one already, I
> > didn't take a look at their sources since January).
> 
> My benchmark say that `buffer-string` takes about 1/3 the time of
> `parse-partial-sexp`, so letting tree-sitter access our buffer text
> directly is unlikely to give more than a 30% speed up.

Sure, but we never call parse-partial-sexp on the entire buffer, do
we?

> It doesn't mean it wouldn't be a desirable optimization, but it does
> mean that it likely won't make a large difference as to whether it's
> "fast enough".

I disagree.  Communicating with a C library by making a string out of
buffer text is extremely inelegant and inefficient.  We shouldn't do
that except when the strings are very short.