The Lezer Parser System
lezer.codemirror.net
lezer.codemirror.net
The linked blog post [0] answered my question though:
> Unfortunately, tree-sitter is written in C, which is still awkward to run in the browser (and CodeMirrror targets non-WASM browsers). It also generates very hefty grammar files because it makes the size/speed trade-off in a different way than a web system would.
In case anyone else was wondering, this is a LR parser-generator that is supposed to be error-insensitive. Here is a java grammar written in it: https://github.com/lezer-parser/java/blob/main/src/java.gram... which doesn't look terrible.