https://stackoverflow.com/questions/44526559/how-to-limit-value-type-code-duplication

PrintAngle.cs

// Consider the following calls:
//   PrintAngle((Radians) 0.10, "radians");
//   PrintAngle((Degrees) 30, "degrees");
// Obviously no conversion are required, but without the IAngularUnit
// interface, we would have to provide copies of this method for each
// Unit manually. 
public static void PrintAngle<TAngularUnit>(TAngularUnit angle, string unit) where TAngularUnit : IAngularUnit {
    switch (unit) {
        case "radians": System.Console.WriteLine("{0:F2} rad", (float) angle.ToRadians); break;
        case "degrees": System.Console.WriteLine("{0:F2} deg", (float) angle.ToDegrees); break;
        case "revolutions": System.Console.WriteLine("{0:F2} rev", (float) angle.ToRevolutions); break;
    }
}

// Calling PrintAngleTakingRadians((Degrees) 30, "degrees")
// will perform two unnecessary conversions: 1) from Degrees to Radians when calling 
// and 2) from Radians to Degrees in the switch statement. To solve it without the
// interface, we would have to overload the function taking each possible unit.
public static void PrintAngleTakingRadians(Radians angle, string unit) {
    switch (unit) {
        case "radians": System.Console.WriteLine("{0:F2} rad", (float) angle); break;
        case "degrees": System.Console.WriteLine("{0:F2} deg", (float) (Degrees) angle); break;
        case "revolutions": System.Console.WriteLine("{0:F2} rev", (float) (Revolutions) angle); break;
    }
}