as3 boolean variable won't pass out of function

Question

For some reason my value is not being updated outside of the function. I'm trying to make a button, instanced "plus", move a movie clip "topArrow" constantly upward. I figured the boolean would be an easy way to trigger this, but it isn't being updated outside of the function. Why is this?

import flash.events.Event;
import flash.events.MouseEvent;

var speed:Number = 1;

plus.addEventListener(MouseEvent.MOUSE_DOWN, arrow_up);
plus.addEventListener(MouseEvent.MOUSE_UP, arrow_stop);
minus.addEventListener(MouseEvent.MOUSE_DOWN, arrow_down);
minus.addEventListener(MouseEvent.MOUSE_UP, arrow_stop);

var move_up:Boolean = false;
var move_down:Boolean = false;



function arrow_up(event:MouseEvent):void
{
    trace("button pressed");
    move_up = true;
}


function arrow_stop(event:MouseEvent):void
{

    move_up = false;
    move_down = false;
}

function arrow_down(event:MouseEvent):void
{

    move_down = true;
}

while (move_up==true)
{
    topArrow.y +=  speed;
}

while (move_down==true)
{
    topArrow.y -=  speed;
}

if(move_up)
{
    trace("true");
}

Answer 1

Those while loops are scary, once move_up is true it will go into that loop and never exit?

I would do something like the below instead to animate the movie clip :

var speed:Number = 1;

plus.addEventListener(MouseEvent.MOUSE_DOWN, arrow_up);
plus.addEventListener(MouseEvent.MOUSE_UP, arrow_stop);
minus.addEventListener(MouseEvent.MOUSE_DOWN, arrow_down);
minus.addEventListener(MouseEvent.MOUSE_UP, arrow_stop);

stage.addEventListener(Event.ENTER_FRAME, onEnterFrame);

var move_up:Boolean = false;
var move_down:Boolean = false;

function arrow_up(event:MouseEvent):void
{
    trace("button pressed");
    move_up = true;
}

function arrow_stop(event:MouseEvent):void
{
    move_up = false;
    move_down = false;
}

function arrow_down(event:MouseEvent):void
{
    move_down = true;
}

function onEnterFrame(event:Event):void
{
   if(move_up)
       topArrow.y += speed;
   else if(move_down)
       topArrow.y -=speed;

   if(move_up)
   {
      trace("true");
   }
}