/**
* Checks if the specified item is a QName. Returns the item or throws an exception.
*
* @param it item
* @param empty allow empty result
* @return QNm item
* @throws QueryException query exception
*/
protected final QNm toQNm(final Item it, final boolean empty) throws QueryException {
if (empty && it == null) return null;
final Type ip = checkNoEmpty(it, AtomType.QNM).type;
if (ip == AtomType.QNM) return (QNm) it;
if (ip.isUntyped()) throw NSSENS_X_X.get(info, ip, AtomType.QNM);
throw castError(it, AtomType.QNM, info);
}
@Override
public Expr optimize(final QueryContext ctx, final VarScope scp) throws QueryException {
final SeqType s0 = expr[0].type();
final SeqType s1 = expr[1].type();
final Type t0 = s0.type;
final Type t1 = s1.type;
if (t0.isNumberOrUntyped() && t1.isNumberOrUntyped()) {
final Occ occ = s0.one() && s1.one() ? Occ.ONE : Occ.ZERO_ONE;
type = SeqType.get(Calc.type(t0, t1), occ);
} else if (s0.one() && s1.one()) {
type = SeqType.ITEM;
}
return optPre(oneIsEmpty() ? null : allAreValues() ? item(ctx, info) : this, ctx);
}
@Override
public Type union(final Type t) {
if (instanceOf(t)) return t;
if (t instanceof ArrayType) {
final ArrayType mt = (ArrayType) t;
return mt.instanceOf(this) ? this : get(retType.union(mt.retType));
}
return t instanceof MapType ? ANY_FUN : t instanceof FuncType ? t.union(this) : AtomType.ITEM;
}
/**
* Checks if the specified item is a number. Returns a token representation or throws an
* exception.
*
* @param it item to be checked
* @return number
* @throws QueryException query exception
*/
protected final long toLong(final Item it) throws QueryException {
final Type ip = checkNoEmpty(it, AtomType.ITR).type;
if (ip.instanceOf(AtomType.ITR) || ip.isUntyped()) return it.itr(info);
throw castError(it, AtomType.ITR, info);
}
/**
* Checks if the specified item is a boolean. Returns the boolean or throws an exception.
*
* @param it item be checked
* @return boolean
* @throws QueryException query exception
*/
protected final boolean toBoolean(final Item it) throws QueryException {
final Type ip = checkNoEmpty(it, AtomType.BLN).type;
if (ip == AtomType.BLN) return it.bool(info);
if (ip.isUntyped()) return Bln.parse(it.string(info), info);
throw castError(it, AtomType.BLN, info);
}
/**
* Checks if the specified non-empty item is a string. Returns its value as token or throws an
* exception.
*
* @param it item to be checked
* @return token
* @throws QueryException query exception
*/
protected final byte[] toToken(final Item it) throws QueryException {
final Type ip = it.type;
if (ip.isStringOrUntyped()) return it.string(info);
throw it instanceof FItem ? FIATOM_X.get(info, it.type) : castError(it, AtomType.STR, info);
}