I see it also supports multi-language Documents.

在 2020年1月3日 +0800 PM6:05，Eli Zaretskii <eliz@gnu.org>，写道：
> Would someone like to try to figure out how we could use the
> incremental parsing technology in Emacs for making our
> programming-language support more accurate and efficient? One package
> that implements this technology is tree-sitter:
>
> https://tree-sitter.github.io/tree-sitter/
>
> AFAIU, these capabilities could be used as an alternative to
> regexp- and syntax-pps-based font-lock, better code folding,
> completion, refactoring, and other similar features; in general, any
> feature which would benefit from having a parse tree for the source
> code in a buffer.
>
> To be able to use such libraries, we need to figure out how to
> integrate them into the core, what kind of interfaces would be needed
> for that, and what kind of infrastructure we would need for basing
> Lisp features on those libraries. Posting practical ideas for design
> of all that would be a good first step in this promising direction.
> Bonus points for providing code patches that demonstrate the
> implementation of these ideas.
>
> TIA
>