Hey, I’m a founder of Nextjournal and one of the authors of clojure-mode.
Highly recommend checking out CodeMirror 6 [1], it’s really well done. On of the main benefits is its blazingly fast incremental parsing system called lezer [2], which is heavily influenced by tree-sitter. The Clojure grammar file is at [3].
I’ve done a small video about this at launch [4] and you can also play with this on Nextjournal [5].