The best thing about this is that there is emulated thread management via setTimeout going on underneath to allow for Ctrl-C and other interactivity while thing

The best thing about this is that there is emulated thread management via setTimeout going on underneath to allow for Ctrl-C and other interactivity while things are running. No background workers, no running things on the server, this is some single-page engineering goodness. It implements proper tail calls, too, so it looks like you can run `(define (f) (f)) (f)` forever. Cool stuff, this is one of the most robust single-page REPL experiences I've seen.