DocumentSet docs = contextSequence.getDocumentSet();
Item query = getKey(contextSequence, null);
Properties options = parseOptions(contextSequence, null);
try {
if (Type.subTypeOf(query.getType(), Type.ELEMENT))
preselectResult = index.queryField(context, getExpressionId(), docs, useContext ? contextSequence.toNodeSet() : null,
field, (Element) ((NodeValue)query).getNode(), NodeSet.DESCENDANT, options);
else
preselectResult = index.queryField(context, getExpressionId(), docs, useContext ? contextSequence.toNodeSet() : null,
field, query.getStringValue(), NodeSet.DESCENDANT, options);
} catch (IOException | ParseException e) {