import math

struct Exponent {
    value int
}

fn (a Exponent) **(b Exponent) Exponent {
    mut result := 1
    for _ in 0 .. b.value {
        result *= a.value
    }
    return Exponent{
        value: result
    }
}

const const_power = 2 ** 5

fn test_power_operator_with_ints() {
    assert const_power == 32
    assert 2 ** 3 == 8
    assert 2 ** 3 ** 2 == 512
    assert -2 ** 2 == -4
    assert (-2) ** 2 == 4
}

fn test_power_assign_with_ints() {
    mut value := 3
    value **= 3
    assert value == 27
}

fn test_power_operator_with_floats() {
    assert math.abs(9.0 ** 0.5 - 3.0) < 1e-9
}

fn test_power_operator_overload() {
    mut value := Exponent{
        value: 2
    }
    assert (value ** Exponent{
        value: 3
    }).value == 8
    value **= Exponent{
        value: 3
    }
    assert value.value == 8
}