@Override
  public void initExprents() {

    IfExprent ifexpr = (IfExprent)first.getExprents().remove(first.getExprents().size() - 1);

    if (negated) {
      ifexpr = (IfExprent)ifexpr.copy();
      ifexpr.negateIf();
    }

    headexprent.set(0, ifexpr);
  }
@Override
  public void initExprents()