Method sum

basex-core/src/main/java/org/basex/query/func/fn/FnSum.java:151–181

Sums up the specified item(s). @param avg calculate average @param qc query context @return summed up item @throws QueryException query exception

(final boolean avg, final QueryContext qc)

   * @throws QueryException query exception
   */
  final Item sum(final boolean avg, final QueryContext qc) throws QueryException {
    final Expr values = arg(0);
    if(values instanceof Range) return range(values.value(qc), avg);

    final Iter iter = values.atomIter(qc, info);
    final Item item = iter.next();
    if(item == null) return null;

    Item result = item.type.isUntyped() ? Dbl.get(item.dbl(info)) : item;
    final Type type = result.type;
    final boolean num = result instanceof ANum;
    final boolean dtd = type == DAY_TIME_DURATION, ymd = type == YEAR_MONTH_DURATION;
    if(!num && !dtd && !ymd) throw NUMDUR_X_X.get(info, type, result);

    int c = 1;
    for(Item it; (it = qc.next(iter)) != null;) {
      final Type tp = it.type;
      Type t = null;
      if(tp.isNumberOrUntyped()) {
        if(!num) t = DURATION;
      } else if(num) {
        t = NUMERIC;
      } else if(dtd && tp != DAY_TIME_DURATION || ymd && tp != YEAR_MONTH_DURATION) {
        t = DURATION;
      }
      if(t != null) throw ARGTYPE_X_X_X.get(info, t, tp, it);
      result = Calc.ADD.eval(result, it, info);
      c++;
    }
    return avg ? Calc.DIVIDE.eval(result, Itr.get(c), info) : result;
  }
}