abstract sclass AIStrategy<A> implements Steppable {
  // user must set
  F1<A, Double> submit; // scoring function
  
  *() {}
  *(F1<A, Double> *submit) {}
  
  selfType setJudge(IF1<A, Number> judge) {
    submit = func(A a) -> double { judge.get(a).doubleValue() };
    this;
  }
  
  long round;
  new Best<A> best;
  bool verbose;
  event newBest(A guess, double score);
  
  void updateBest(A guess, double score) {
    if (best.put(guess, score))
      newBest(guess, score);
  }
  
  double submit(A guess) {
    if (guess == null) ret best.worstScore();
    double score = callF(submit, guess);
    updateBest(guess, score);
    ret score;
  }
  
  selfType lowerIsBetter(bool b) {
    best.lowerIsBetter(b);
    this;
  }
}