sclass BestWorstAndAverage<A> {
  IBest<A> best = new Best;
  IBest<A> worst = new Lowest;
  new Average average;
  
  selfType lowerIsBetter() {
    best = new Lowest;
    worst = new Best;
    this;
  }

  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);
  }
}