@stfnieJoeng #29 pub fn Double::from_int(i : Int) -> Double {
i.to_double()
}

pub fn abs(self : Double) -> Double {
if self < 0.0 {
-self
} else {
self
}
}

/// Returns the sign of the double.
/// - If the double is positive, returns 1.0.
/// - If the double is negative, returns -1.0.
/// - Otherwise, returns the double itself (0.0, -0.0 and NaN).
pub fn signum(self : Double) -> Double {
if self < 0.0 {
-1.0
} else if self > 0.0 {
1.0
} else {
self // handles 0.0, -0.0, NaN
}
}

fn test_num[T : @num.Num + Debug + Default + Eq](
x : T,
y : T,
x_plus_y : T,
x_mul_y : T,
x_minus_y : T,
x_div_y : T,
x_signum : T
) -> Result[Unit, String] {
@assertion.assert_eq(x + y, x_plus_y)?
@assertion.assert_eq(x * y, x_mul_y)?
@assertion.assert_eq(x - y, x_minus_y)?
@assertion.assert_eq(x / y, x_div_y)?
@assertion.assert_eq(x.abs(), T::default() - x)?
@assertion.assert_eq(x.signum(), x_signum)?
Ok(())
}

test "double.num" {
let x = -500.0
let y = 792.0
test_num(x, y, x + y, x * y, x - y, x / y, -1.0)?
}
这代码确定不是小学生写着玩的？
这开源一点也不真诚