Can I use variables in mxml tags?

Question

I want to control a lot of details in a layout.  I need to use variables to do this.  Of course I can use AS.  Is there a way to do it in the MXML tags?  See the code below.  I can do the "myLine.x = lineX" in AS.  But is there something like:  x="{lineX}" to use in a tag?  (This gives a warning, though it does work.)  It would make life faster if I could...   Is there a "right" way to do this?
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
               xmlns:s="library://ns.adobe.com/flex/spark"
               xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600"
               initialize="init()" >
    <fx:Declarations>
        <!-- Place non-visual elements (e.g., services, value objects) here -->
    </fx:Declarations>
    <fx:Script>
        <![CDATA[
            internal var lineX:Number = 25;
            private function init():void {
                myLine.x = lineX + 50;       
        ]]>
    </fx:Script>
    <s:Line id="myLine" xFrom="0" xTo="0" yFrom="50" yTo="300" >
        <s:stroke>
            <s:SolidColorStroke color="0x0000ff" weight="2" />
        </s:stroke>
    </s:Line>
    <s:Line id="myOtherLine" x="{lineX}" xFrom="0" xTo="0" yFrom="50" yTo="300" >
        <s:stroke>
            <s:SolidColorStroke color="0xff0000" weight="2" />
        </s:stroke>
    </s:Line>
</s:Application>

Answer 1

Hmm, thanks, that's very useful to know.
I guess that means I should use AS.  It's not something I need to update often.  Rather, I have a whole bunch of groups of components/graphics that I want to line up based on each other--and when I change my mind about the size or position of one thing (possibly inside a container a level or two), I'd like to be able to just change one variable name rather than have to change them all by hand.  But AS can do it just fine.