sclass BestWorstAndAverage<A> {
  new Best<A> best;
  new Lowest<A> worst;
  new Average average;

  bool put(A a, double score) {
    average.add(score);
    ret best.put(a, score) | worst.put(a, score);
  }
  
  toString {
    ret renderVars(avg := average, +best, +worst);
  }
}