cmd = new Object();

function initCommands(){

  cmd.move = _move;

  player.cmd = cmd;
}

function _move( xDelta, yDelta ){
  if( !cave[player.x + xDelta][player.y + yDelta].isOccupied() ){
    player.x = player.x + xDelta;
    player.y = player.y + yDelta;
    view.showCave();
  }
}