persistable sclass PercentIncrease {

  settable double percentIncrease;

  *(double *percentIncrease) {}

  double get() { ret percentIncrease; }

  double asFactor aka factor aka getFactor() { ret 1+percentIncrease/100; }

  static PercentIncrease of(double percentIncrease) {

    ret new PercentIncrease(percentIncrease);

  }

  static PercentIncrease fromFactor(double factor) {

    ret new PercentIncrease((factor-1)*100);

  }

  toString { ret plusMinusFix(formatDouble_significant(percentIncrease, 4)) + "%"; }

  PercentIncrease combineWith aka mul(PercentIncrease i) {

    ret fromFactor(asFactor()*i.asFactor());

  }

  double applyTo aka mul(double x) {

    ret asFactor()*x;

  }

  // gets the n-th root (an increase you can apply n times to get the original one)

  PercentIncrease root aka nthRoot(double n) {

    ret fromFactor(Math.pow(asFactor(), 1/n));

  }

  // gets the n-th power (an increase you can apply n times to get the original one)

  PercentIncrease pow aka repeat(double n) {

    ret fromFactor(Math.pow(asFactor(), n));

  }

}