// pairs of (result, module id)
static L<Pair<S>> dm_universalSearch(S query) {
  new L<Pair<S>> out;
  for (O m : dm_listModules()) {
    S result = pcallOpt(dm, 'uSearch, query);
    if (nempty(result))
      out.add(pair(result, dm_moduleID(m));
  }
  ret out;
}