!7

sclass Parser {
  new StringTree2 tree;
  
  L<S> tok(S s) { ret javaTok(s); }
  L<S> tokC(S s) { ret javaTokC(s); }
  
  void register(S text, O action) {
    addToStringTree(tree, tokC(text), action);
  }
  
  Parsing parse(S text) {
    ret nu(Parsing,
      parser := this, it := tokC(text).iterator(),
      treesInFlight := ll(new InFlight(tree)));
  }
}

sclass InFlight {
  new L history;
  StringTree2 tree;
  
  *() {}
  *(StringTree2 *tree) {}
  *(L *history, StringTree2 *tree) {}
}

sclass Parsing {
  Parser parser;
  Iterator<S> it;
  new L<InFlight> treesInFlight;
  
  void run {
    while (it.hasNext()) step();
  }
  
  void step {
    S token = it.next();
    for i over treesInFlight: {
      InFlight tree = treesInFlight.get(i);
      StringTree2 tree2 = tree.tree.get(token);
      if (tree2 == null) treesInFlight.remove(i--);
      else treesInFlight.set(i, new InFlight(tree.history, tree2));
    }
    actions();
  }
  
  void actions {
    for (StringTree2 tree : treesInFlight)
      if (tree! != null)
        runAction(tree!);
  }
  
  void runAction(O o) {
    print("Action! " + struct(o));
  }
}

p {
  new Parser p;
  p.register("I am here", "I-am-here");
  Parsing pp = p.parse("yo I am here");
  pp.run();
}