Is there a way to import using MXML?

Question

This works but is kinda clumsy. It would be more elegant if
there was a way of doing an "import" using MXML (e.g. mx:Component
import="mx.controls.Alert" or something like that). Is there a way
to do an "import" without having to resort to mx:Script?
<mx:itemRenderer>
___<mx:Component>
______<mx:Button label="Sell" click="Alert.show('Do you
want to procede?' , 'Sell Trade' , Alert.OK | Alert.CANCEL )" >
_________<mx:Script>
____________<![CDATA[
_______________import mx.controls.Alert ;
____________]]>
_________</mx:Script>
______</mx:Button>
___</mx:Component>
</mx:itemRenderer>

Answer 1

In-line renderers are themselves kind of clumsy. Just create
your renderer as an external component instead. It is much cleaner.
"Is there a way to create your own custom MXML tags?"
Absolutely. Any custom component can be instantiated using mxml.
Tracy