<'
struct base_object {
   addr : byte;
   data : byte;
};

struct keyed_list {
  !memory  : list (key:addr) of base_object;
  // writing to a keyed list
  write_item(object : base_object) is {
     memory.add(object); 
     print object;
  };
  // Reading from keyed list
  read_item(object : base_object) is {
     var local_object : base_object = memory.key(object.addr);
     print local_object;
  };
};
// Just to check our code
extend sys {
  data      : base_object;
  mem_model : keyed_list;
  run() is also {
    gen data;
    mem_model.write_item(data);
    mem_model.read_item(data);
  };
};
'>