state.ml

type state = Init | Started | Stopped

type init_event = InitStart | InitStop

type started_event = StartedStop

type stopped_event = StoppedStart

let init_event () =
  List.nth [InitStart; InitStop] (Random.int 1)

let started_event () = StartedStop

let stopped_event () = StoppedStart

let apply = function
  | Init -> begin
    match init_event () with
    | InitStart -> Started
    | InitStop -> Stopped end
  | Started -> begin
      match started_event () with
      | StartedStop -> Stopped end
  | Stopped -> begin
      match stopped_event () with
      | StoppedStart -> Started end

let () =
  let rec tick s =
    tick (apply s) in
  tick Init