// $XA
//
// $XA(exp, context, resolver)(function(node){});
function $XA(exp, context, resolver) {
	context || (context = document);
	var XPE = new XPathEvaluator();
	var Doc = context.ownerDocument || context, expr = XPE.createExpression(exp, resolver ? resolver :
		Doc.documentElement.namespaceURI ? function(prefix) {
			return XPE.createNSResolver(Doc.documentElement).lookupNamespaceURI(prefix) ||
			context.namespaceURI || document.documentElement.namespaceURI || "";
	} : null);
	var result = expr.evaluate(context, XPathResult.ANY_TYPE, null);
	switch (result.resultType) {
	case XPathResult.STRING_TYPE : return function(fnc,thisObject) {fnc.call(thisObject,result.stringValue);};
	case XPathResult.NUMBER_TYPE : return function(fnc,thisObject) {fnc.call(thisObject,result.numberValue);};
	case XPathResult.BOOLEAN_TYPE: return function(fnc,thisObject) {fnc.call(thisObject,result.booleanValue);};
	case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
		result = expr.evaluate(context, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, result);
		return function(fnc, thisObject) {
			for (var i = 0, len = result.snapshotLength; i < len; i++) {
				fnc.call(thisObject, result.snapshotItem(i));
			}
		};
	}
	return null;
}