persistable sclass ROCIndicator extends CandleBasedIndicator<Double> {
  // ROC values collected as ticker
  gettable TickerSequence rocHistory = new TickerSequence("ROC");
  
  // ATR value
  settable double roc = Double.NaN;

  Double value() { ret roc(); }
  
  *(int *length) {}

  {
    length = 10;
    
    onCandleAdded((IVF1<TradingCandle>) candle -> {
      if (l(candles()) >= length) {
        roc(asPercentIncrease(candle.close(), candles().first().close()));

        long time = candle.endTime().toLong();
        rocHistory?.addIfPriceChanged(roc, time);
      }
    });
  }
  
  TickerSequence asTicker(L<TradingCandle> candles) {
    feed(candles);
    ret rocHistory;
  }
  
  void reset :: after {
    resetFields(this, "roc rocHistory");
  }
}

Began life as a copy of #1036469