use rust_num::{Float, NumCast};
use rust_num::traits::cast;
pub trait ApproxEq<T: NumCast + Float>: Sized {
fn approx_epsilon(_hack: Option<Self>) -> T {
cast(1.0e-5f64).unwrap()
}
fn approx_eq(&self, other: &Self) -> bool {
let eps: T = ApproxEq::approx_epsilon(None::<Self>);
self.approx_eq_eps(other, &eps)
}
fn approx_eq_eps(&self, other: &Self, epsilon: &T) -> bool;
}
macro_rules! approx_float(
($S:ident) => (
impl ApproxEq<$S> for $S {
#[inline]
fn approx_eq_eps(&self, other: &$S, epsilon: &$S) -> bool {
(*self - *other).abs() < *epsilon
}
}
)
);
approx_float!(f32);
approx_float!(f64);
#[macro_export]
macro_rules! assert_approx_eq_eps(
($given: expr, $expected: expr, $eps: expr) => ({
let eps = &($eps);
let (given_val, expected_val) = (&($given), &($expected));
if !given_val.approx_eq_eps(expected_val, eps) {
panic!("assertion failed: `left ≈ right` (left: `{:?}`, right: `{:?}`, tolerance: `{:?}`)",
*given_val, *expected_val, *eps
);
}
})
);
#[macro_export]
macro_rules! assert_approx_eq(
($given: expr, $expected: expr) => ({
let (given_val, expected_val) = (&($given), &($expected));
if !given_val.approx_eq(expected_val) {
panic!("assertion failed: `left ≈ right` (left: `{:?}`, right: `{:?}`, tolerance: `{:?}`)",
*given_val, *expected_val,
ApproxEq::approx_epsilon(Some(*given_val))
);
}
})
);