!7

abstract sclass InFlight {

  L actions() { null; }

  abstract L<InFlight> consumeToken(S token);

}

InFlight > JustAction {

  O action;

  *() {}

  *(O *action) {}

  L actions() { ret ll(action); }

  L<InFlight> consumeToken(S token) { null; }

}

InFlight > AcceptWord {

  S word;

  InFlight next;

  *() {}

  *(S *word, InFlight *next) {}

  L<InFlight> consumeToken(S token) {

    if (!eqic(token, word)) null;

    ret ll(next);

  }

}

sclass Parsing {

  Iterator<S> it;

  new L<InFlight> inFlight;

  *(S text, InFlight... l) {

    addAll(inFlight, l);

    it = javaTokC(text).iterator();

  }

  void run {

    actions();

    while (it.hasNext()) step();

  }

  void step {

    S token = it.next();

    new L<InFlight> l2;

    for (InFlight f : inFlight)

      addAll(l2, f.consumeToken(token));

    print("New number: " + l(l2));

    inFlight = l2;

    actions();

  }

  void actions {

    for (InFlight f : inFlight)

      for (O action : unnull(f.actions()))

        runAction(action);

  }

  void runAction(O o) {

    print("Action! " + struct(o));

  }

}

p {

  Parsing pp = new Parsing("I am here",

    JustAction("start"),

    AcceptWord("yes", JustAction("yes")),

    AcceptWord("i", AcceptWord("am", AcceptWord("here",

      JustAction("I am here!"));

  pp.run();

}