My first thought was wondering why this couldn't be partially implemented (i.e. the important bits like memoisation of idempotent, state-bound functions or cont

My first thought was wondering why this couldn't be partially implemented (i.e. the important bits like memoisation of idempotent, state-bound functions or contexts) in any other programming language. Then I wondered if this was already implemented for some functional languages. Then I read your comment. It was quite the ride.