static Set<ES> applyAttractors_es(L<IAttractor> attractors, ES s) {
  ret concatListsToCISet_es(map(attractors, attractor ->
    attractor.matches_public(s!) ? getStringEmits_es(attractor) : null
  );
}

static Set<ES> applyAttractors_es(L<IAttractor> attractors, Collection<ES> inputs) {
  Set<ES> out = cloneLinkedCISet_es(inputs);
  for unnull (ES input : inputs)
    functionReturningList_transitiveHull_ciSet_es(func(ES s) -> Collection<ES> { applyAttractors_es(attractors, s) }, input, seen := out);
  ret out;
}