persistable class Position extends G22TradingStrategy.Position {
    settable AbstractJuicer juicer;
    
    toString {
      ret super.toString()
        + (juicer == null ? "" : ". " + commaCombine(juicer.currentSignals()));
    }
  }
  
  srecord ProfitBeforeLeverageJuiceable(Position p) is Juiceable {
    public double juiceValue() { ret p.profitBeforeLeverage(); }
  }
  
  void juiceStrategy_price(double price) {
    if (currentPrice == price) ret;
    currentPrice = price;
    afterwards { afterStep(); change(); }
    juiceStrategy_newPrice(price);
  }
    
  void juiceStrategy_newPrice(double price) {
    for (p : openPositions()) {
      cast p to Position;
      
      if (p.juicer != null) {
        var signals = p.juicer.calculateCloseSignals();
        var strongest = highestBy(signals, s -> s.strength());
        if (strongest != null && strongest.isTrigger()) {
          p.close(strongest);
        }
      }
    }
  }
  
  Position openShort() { ret openPosition(-1); }
  Position openLong() { ret openPosition(1); }
  
  Position openPosition(int direction, O openReason default null) {
    new Position p;
    p.marginToUse = marginToUseForNewPosition();
    addJuicer(p);
    ret openPosition(p, direction, openReason);
  }
  
  void addJuicer(Position p) {
    var j = makeJuicer();
    if (j == null) ret;
    j.copyTransientValuesFrom(p.juicer);
    j.juiceable(new ProfitBeforeLeverageJuiceable(p));
    p.juicer(j);
  }
  
  void recreateJuicersForExistingPositions aka updateJuicers() {
    for (p : openPositions()) {
      cast p to Position;
      addJuicer(p);
    }
  }
  
  L<? extends Position> openPositions() { ret (L) super.openPositions(); }
  
  L<AbstractJuicer> allJuicers aka juicers() {
    ret map(openPositions(), -> .juicer());
  }