/**
* Checks if the items can be compared. Items are comparable
*
* @param b second item
* @return result of check
*/
public final boolean comparable(final Item b) {
return type == b.type
|| num() && b.num()
|| (unt() || str()) && (b.str() || b.unt())
|| dur() && b.dur()
|| func();
}
/**
* Checks the items for equivalence.
*
* @param ii input info
* @param it item to be compared
* @return result of check
* @throws QueryException query exception
*/
public final boolean equiv(final InputInfo ii, final Item it) throws QueryException {
// check if both values are NaN, or if values are equal..
return (this == Dbl.NAN || this == Flt.NAN) && it.num() && Double.isNaN(it.dbl(ii))
|| comparable(it) && eq(ii, it);
}