/**
* Return an iterator over the results of the expression, given an iterator over the principal
* operand to the expression
*
* @param base an interator over the input to the expression
* @param context dynamic evaluation context
* @return an iterator over the results of the expression
* @throws XPathException
*/
public SequenceIterator getMappingIterator(SequenceIterator base, XPathContext context)
throws XPathException {
boolean b = isInstance(base, context);
return SingletonIterator.makeIterator(BooleanValue.get(b));
}
/** Evaluate the expression */
public Item evaluateItem(XPathContext context) throws XPathException {
return BooleanValue.get(effectiveBooleanValue(context));
}