Expi.Makemodule M : Monads.Std.Monad.State.S2type ('a, 'e) state = ('a, 'e) M.ttype 'a u = (unit, 'a) statetype 'a r = (Bil.result, 'a) statemodule M : Core_kernel.T2 with type ('a, 'e) t = ('a, 'e) stateclass 'a t : object ... endExpression interpreter.