Support multi-language documents

Now that Cursorless supports HTML (great job!) it would be amazing if it could also support nested languages inside of HTML. For example JS/TS inside of <script> tags, and CSS/SCSS inside of <style> tags.

This would be super helpful for web developers. Because plenty of popular frameworks (such as Vue) use single file components, where HTML, JS and CSS are all located in the same file.

I assume that this documentation is relevant to this issue: https://tree-sitter.github.io/tree-sitter/using-parsers#multi-language-documents

• JS and CSS support inside of HTML
• Code blocks within markdown

[pokey]

Awesome! Solid research. We should think about how this connects to rewriting our language defs using this query language. Cc/ @wenkokke

One minor thing I’ll add: helix also maintains its own injection regexes in case for whatever reason we need to steal those. They’re all in one file, see eg rust

[pokey]

It’s also worth thinking bout how this works with incremental parsing

Yep! This query can happen off of any SyntaxNode, I used the rootNode as an example above.

Just to be clear, by “incremental parsing”, I mean updating the parse tree as the document changes, which tree-sitter is able to do efficiently without reparsing the entire document. Here’s where we do it in the parse-tree extension: https://github.com/cursorless-dev/vscode-parse-tree/blob/4af875b7cbd72d68c1e1eafe43ddabc3403264ce/src/extension.ts#L109-L134