def num_results_for query={}
    xapian_query = build_xapian_query query
    matchset = run_query xapian_query, 0, 0, 100
    matchset.matches_estimated
  end
def num_results_for query={}
    xapian_query = build_xapian_query query
    matchset = run_query xapian_query, 0, 0, 100
    matchset.matches_estimated
  end
Return the number of matches for query in the index