为撒不行？

为撒不行？

类似迷宫游戏，为什么成功不了啊，刚学AS3   帮忙啊 ！！！！
addEventListener(Event.ENTER_FRAME,mo);
var dd:Boolean=false;
  var ud:Boolean=false;
  var ld:Boolean=false;
  var rd:Boolean=false;

function mo(event:Event){
if(people.hitTestObject(wall));
else {mov;}        }
function mov(event:Event){
  
  people.addEventListener(KeyboardEvent.KEY_DOWN,keyPressedDown);
  people.addEventListener(KeyboardEvent.KEY_UP,keyPressedUp);
  people.addEventListener(Event.ENTER_FRAME,don);
  }
function keyPressedDown(event:KeyboardEvent){
  if(event.keyCode == 37){
   ld=true;}
   if(event.keyCode == 38){
   ud=true;}
   if(event.keyCode == 39){
   rd=true;}
   if(event.keyCode == 40){
   dd=true;}}
  function keyPressedUp(event:KeyboardEvent){
   if(event.keyCode == 37){
   ld=false;}
   if(event.keyCode == 38){
   ud=false;}
   if(event.keyCode == 39){
   rd=false;}
   if(event.keyCode == 40){
   dd=false;}}
   function don(event:Event){
    var sped:int=5;
    if(ld){
     people.x-=sped;
     }
        if(ud){
     people.y-=sped;
     }
     if(rd){
     people.x+=sped;
     }
     if(dd){
     people.y+=sped;
     }
   }