@Override
public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
final QNm name = toQNm(exprs[0], qc, sc, false);
final long arity = toLong(exprs[1], qc);
if (arity < 0 || arity > Integer.MAX_VALUE) throw FUNCUNKNOWN_X.get(ii, name);
try {
final Expr lit = Functions.getLiteral(name, (int) arity, qc, sc, ii);
return lit == null ? null : lit.item(qc, ii);
} catch (final QueryException e) {
// function not found (in most cases: XPST0017)
return null;
}
}
/**
* Checks if the specified expression yields a string or empty sequence. Returns a token
* representation or an exception.
*
* @param e expression to be evaluated
* @param ctx query context
* @return item
* @throws QueryException query exception
*/
public final byte[] checkEStr(final Expr e, final QueryContext ctx) throws QueryException {
return checkEStr(e.item(ctx, input));
}
/**
* Checks if the specified expression yields a non-empty item.
*
* @param e expression to be evaluated
* @param ctx query context
* @return item
* @throws QueryException query exception
*/
public final Item checkItem(final Expr e, final QueryContext ctx) throws QueryException {
return checkEmpty(e.item(ctx, input));
}
/**
* Checks if the specified expression is an integer. Returns a token representation or an
* exception.
*
* @param e expression to be checked
* @param ctx query context
* @return integer value
* @throws QueryException query exception
*/
public final long checkItr(final Expr e, final QueryContext ctx) throws QueryException {
return checkItr(checkNoEmpty(e.item(ctx, input), AtomType.ITR));
}
/**
* Checks if the specified expression yields a double. Returns the double or throws an exception.
*
* @param e expression to be checked
* @param ctx query context
* @return double
* @throws QueryException query exception
*/
public final double checkDbl(final Expr e, final QueryContext ctx) throws QueryException {
final Item it = checkNoEmpty(e.item(ctx, input), AtomType.DBL);
if (!it.unt() && !it.num()) Err.number(this, it);
return it.dbl(input);
}
/**
* Checks if the specified expression yields a boolean. Returns the boolean or throws an
* exception.
*
* @param e expression to be checked
* @param ctx query context
* @return boolean
* @throws QueryException query exception
*/
public final boolean checkBln(final Expr e, final QueryContext ctx) throws QueryException {
final Item it = checkNoEmpty(e.item(ctx, input), AtomType.BLN);
if (!it.unt() && it.type != AtomType.BLN) Err.type(this, AtomType.BLN, it);
return it.bool(input);
}
