//look at the comments in the code
 package {
	import flash.accessibility.Accessibility;
    import flash.display.Sprite;
    import flash.events.*;
    import flash.text.TextField;
    
    public class TraceTest extends Sprite {
        
        public function TraceTest() {
            
            inittrace(stage);
            
            var i:int = -1;
            var test:Array = ["a","b","c"];
            
            trace("given test is [",test,"]");
            //But how strange is this:
            trace("for (var i:int = test.length; i--; ){ prints:");
            for (i = test.length; i--; ){
            		trace(test[i]);
            	}
            /*
            from the AS-docs of for:
            for ([init]; [condition]; [next]) { 
				[statement-block]
			}
            
            Of course: the condition is executed before 
            each statement-block, wich decrements it, 
            as if we would have put the same statement
            to [next].
            My first idea was that we would need to write 
            for (var i:int = test.length; --i; ){
            	if this should work at all.
            	but see what happens:*/
            	
            trace("for (var i:int = test.length; --i; ){ prints:");
            for (i = test.length; --i; ){
            		trace(test[i]);
            	}
            	/*
            	lets take a closer look at what happens in 
            	the first for-loop: 
            	format: 
             
             1) [init] var i:int = test.tength // i is 3
             2) [condition]{
             3)   Boolean(i)// i is 3 -> true
             4)	 i= i-1 // i is 2
             5) }
             6) [statement-block] / [next] // i is 2 (==test.length-1)
             7) [condition]{
             8)   Boolean(i)// i is 2 -> true
             9)	 i= i-1 // i is 1
            10) }
            11) [statement-block] / [next] // i is 1
             7) [condition]{
             8)   Boolean(i)// i is 1 -> true
             9)	 i= i-1 // i is 0
            10) }
            11) [statement-block] / [next] // i is 0
             7) [condition]{
             8)   Boolean(i)// i is 0 -> FALSE
             9)	 i= i-1 // i is -1
            10) }
            
            	So there are two thing that wake this work:
            	A) the condition is tested against a value 
            	of i that is not the same as inside the 
            	statement-block. 
            	(it is decremented AFTER the condition!)
            	B) Boolean(0) == false
            	
            	So it looks strange at first,
            	but looking at this: it would be strange
            	if it wouldn't work.
            	
            	Thanks to the inspiration through
            	Robert Penner's
            	http://github.com/robertpenner/as3-signals/blob/master/src/org/osflash/signals/Signal.as
            	inside of 
            	protected function setValueClasses(...) and elsewhere
            	
            	As he stated it in a very simple way:
            	
			>Yes, it's equivalent to:
			>
			>var i:int = _valueClasses.length;
			>while (i--){
			>
            	*/
            	
            	/*
            	some tests started out of confusion:
            	var x:int = 1;
            trace("if x == 1 then Boolean(x--) is",Boolean(x--));
            x=1;
            trace("if x == 1 then Boolean(--x) is",Boolean(--x));
            */
        }
        
    }
}

/////  WONDERFL TRACE /////

import flash.display.Sprite;
import flash.display.Stage;
import flash.text.TextField;
import flash.text.TextFormat;

function inittrace(s:Stage):void
{
    WTrace.initTrace(s);
}

//global trace function
var trace:Function;

//wtreace class
class WTrace
{
        private static var FONT:String = "Fixedsys";
        private static var SIZE:Number = 12;
        private static var TextFields:Array = [];
        private static var trace_stage:Stage;
        
        public static function initTrace(stg:Stage):void
        {
            trace_stage = stg;
            trace = wtrace;
        }
        
        private static function scrollup():void
        {
            // maximum number of lines: 100
            if (TextFields.length > 100) 
            {
                var removeme:TextField = TextFields.shift();
                trace_stage.removeChild(removeme);
                removeme = null;
            }
            for(var x:Number=0;x<TextFields.length;x++)
            {
                (TextFields[x] as TextField).y -= SIZE*1.2;
            }
        }
    
        public static function wtrace(... args):void
        {
        
            var s:String="";
            var tracefield:TextField;
            
            for (var i:int;i < args.length;i++)
            {
                // imitating flash:
                // putting a space between the parameters
                if (i != 0) s+=" ";
                s+=args[i].toString();
            }

tracefield= new TextField();
            tracefield.autoSize = "left";
            tracefield.text = s;
            tracefield.y = trace_stage.stageHeight - 20;

var tf:TextFormat = new TextFormat(FONT, SIZE);
            tracefield.setTextFormat(tf);
            trace_stage.addChild(tracefield);
            scrollup();                      
            TextFields.push(tracefield);
            
        }
}

for with postdecrement as condition