unison/unison-src/tests/state2a-min.u

--State2 ability
ability State s where
  put : s -> {State s} ()

state : s -> Request (State s) a -> a
state s = cases
  { State.put snew -> k } -> handle k () with state snew
  { a } -> a

ex : Text
ex = handle
  State.put (11 + 1)
  State.put (5 + 5)
  "hello"
  with state 10

> ex