SI units for rust. This is started as a sandbox project to learn rust.
let m = Value::new(LengthUnit::Meter, 6.0);
let s = Value::new(TimeUnit::Seconds, 2.0);
let v = m / s; // v is meter per second
assert_eq!(3.0, v.value());
assert_eq!("3m/s", v.to_string());