// always keeps a dynamically updated list of the n most probable
// results

srecord noeq PSCollectMostProbable<A>(IProbabilisticScheduler ps,
  int maxResults,
  IVF1<IVF1<A>> action) {
  
  TreeSetWithDuplicates<WithProbability<A>> results = new(reverseComparator());
  
  void add(WithProbability<A>> result) {
    if (result == null) ret;
    results.add(result);
    truncateTreeSetWithDuplicates(results, maxResults);
  }
  
  selfType run() {
    action.get(result -> add(WithProbability(ps.currentProbability(), result));
    this;
  }
  
  // results sorted by probability. instant
  Set<WithProbability<A>> results() {
    ret results;
  }
}