}
@Override
protected Object evaluate(final Evaluator evaluator) {
Position position = (Position) nullForNA(evaluator.getVariable("position"));
NavigablePortfolioNode node = (NavigablePortfolioNode) nullForNA(evaluator.getVariable("node"));
if ("isNode".equals(_text)) {
return (position == null);
} else if ("isPosition".equals(_text)) {
return (position != null);
} else if ((node != null) && _text.startsWith("Node.")) {