public NodeSet eval(
final NGramIndexWorker index, final DocumentSet docs, final List<QName> qnames, final NodeSet nodeSet,
final int axis, final int expressionId) throws XPathException {
NodeSet result = new ExtArrayNodeSet();
for (String s : strings) {
result.addAll(nGramSearch.fixedStringSearch(index, docs, qnames, s, nodeSet, axis));
}
result.iterate(); // ensure result is ready to use
return result;
}