Comment by sound_and_form

I would have prefered the adjective "clever" over "shocking" :) But you're absolutely correct: it does rely entirely on tail-call optimizations. I hadn't seen this as an actual real world concern. Its stack usage is sufficiently minimal for debugging and development of the project itself. And production code would only ever be optimized. Maybe there are risks I can't foresee, but I'm gonna keep at it 'cause the upside is a blazingly fast interpreter.