@Override
public Item ev(final InputInfo ii, final Item a, final Item b) throws QueryException {
final Type ta = a.type, tb = b.type;
final boolean t1 = ta.isNumber() || ta.isUntyped();
final boolean t2 = tb.isNumber() || tb.isUntyped();
if (t1 ^ t2) errNum(ii, !t1 ? a : b);
if (t1 && t2) {
final Type t = type(ta, tb);
if (t == ITR) {
final long l1 = a.itr(ii);
final long l2 = b.itr(ii);
checkRange(ii, l1 + (double) l2);
return Int.get(l1 + l2);
}
if (t == DBL) return Dbl.get(a.dbl(ii) + b.dbl(ii));
if (t == FLT) return Flt.get(a.flt(ii) + b.flt(ii));
return Dec.get(a.dec(ii).add(b.dec(ii)));
}
if (ta == tb) {
if (!ta.isDuration()) errNum(ii, !t1 ? a : b);
if (ta == YMD) return new YMd((YMd) a, (YMd) b, true);
if (ta == DTD) return new DTd((DTd) a, (DTd) b, true);
}
if (ta == DTM) return new Dtm((Date) a, checkDur(ii, b), true, ii);
if (tb == DTM) return new Dtm((Date) b, checkDur(ii, a), true, ii);
if (ta == DAT) return new Dat((Date) a, checkDur(ii, b), true, ii);
if (tb == DAT) return new Dat((Date) b, checkDur(ii, a), true, ii);
if (ta == TIM) {
if (tb != DTD) errType(ii, DTD, b);
return new Tim((Tim) a, (DTd) b, true, ii);
}
if (tb == TIM) {
if (ta != DTD) errType(ii, DTD, b);
return new Tim((Tim) b, (DTd) a, true, ii);
}
errType(ii, ta, b);
return null;
}
/**
* Returns a duration type error.
*
* @param ii input info
* @param it item
* @return duration
* @throws QueryException query exception
*/
final Dur checkDur(final InputInfo ii, final Item it) throws QueryException {
final Type ip = it.type;
if (!ip.isDuration()) XPDUR.thrw(ii, info(), ip);
if (ip == DUR) throw SIMPLDUR.thrw(ii, info(), it);
return (Dur) it;
}