num-cmp

The NumCmp trait for comparison between differently typed numbers.

use std::f32;
use std::cmp::Ordering;
use num_cmp::NumCmp;

assert!(NumCmp::num_eq(3u64, 3.0f32));
assert!(NumCmp::num_lt(-4.7f64, -4i8));
assert!(!NumCmp::num_ge(-3i8, 1u16));

// 40_000_000 can be exactly represented in f32, 40_000_001 cannot
assert_eq!(NumCmp::num_cmp(40_000_000.0f32, 40_000_000u32), Some(Ordering::Equal));
assert_ne!(NumCmp::num_cmp(40_000_001.0f32, 40_000_001u32), Some(Ordering::Equal));
assert_eq!(NumCmp::num_cmp(f32::NAN,        40_000_002u32), None);

The i128 Cargo feature can be enabled in nightly to get support for i128 and u128 types as well, which is being implemented in Rust issue #35118.