fsm.js

class FSM {
  constructor() {
    this.state = "start";
  }

  responds_to(action) {
    let fsm = this;
    return fsm.states()[fsm.state][action] !== undefined;
  }

  take_action(action) {
    let fsm = this;
    // TODO: Check if state exists
    return fsm.states()[fsm.state][action]();
  }

  update_state(new_state) {
    let fsm = this;
    this.state = new_state;
    return;
  }

  process_epsilons() {
    let fsm = this;
    // TODO: Don't do this indefinitely
    console.log("processing epsilons for ", fsm.state);
    if (fsm.responds_to("epsilon")) {
      return fsm.dispatch("epsilon");
    }
  }

  dispatch(action) {
    let fsm = this;
    console.log("dispatching: " + fsm.state + ", action: " + action);
    return fsm
      .take_action(action)
      .then(new_state => fsm.update_state(new_state))
      .then(() => fsm.process_epsilons());
  }
}

module.exports = FSM;