/**
* 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);
}
/**
* Evaluates the match function.
*
* @param val input value
* @param ctx query context
* @return function result
* @throws QueryException query exception
*/
private Item matches(final byte[] val, final QueryContext ctx) throws QueryException {
final Pattern p = pattern(expr[1], expr.length == 3 ? expr[2] : null, ctx);
return Bln.get(p.matcher(string(val)).find());
}