return null;
switch(other.getType()) { case Type.DATE_TIME: return new DayTimeDurationValue(date.getTime() - ((DateTimeValue) other).date.getTime()); case Type.YEAR_MONTH_DURATION: return ((YearMonthDurationValue) other).negate().plus(this); case Type.DAY_TIME_DURATION: return ((DayTimeDurationValue) other).negate().plus(this); default: throw new XPathException( "Operand to minus should be of type xs:dateTime, xdt:dayTimeDuration or xdt:yearMonthDuration; got: " + Type.getTypeName(other.getType())); }
	public ComputableValue minus(ComputableValue other) throws XPathException {		// TODO Auto-generated method stub		return null;	}