concept G22PassiveTradingStrategy extends G22TradingStrategy {
  // A regular expression that will be used to match
  // the orderID or comment coming from TradingView to
  // distinguish this strategy from others on the same coin.
  settableWithVar S tradingViewRegexp;
  
  void price(double price) {
    if (currentPrice == price) ret;
    currentPrice = price;
    afterStep(); change();
  }
  
  bool tradingViewMatch(S text) {
    ret empty(tradingViewRegexp) || regexpMatches(tradingViewRegexp, text);
  }
}