Silly mistake - failed to change method when .new changed behaviour.
Add .prompt (and .get-opener, .get-closer) Remove dead code / pointless comments.
Was actually broken in nom before - not sure when that happened. Hopefully this represents the most-correct state.
Rethink. Workaround. Not sure which bugs are mine and which are Rakudo's. Still zero success running in Niecza.
Perparing for greater refactor.