Lately I've been playing around with static dimensional analysis in Rust. The overall idea is similar: Use PhantomData to add a type parameter and define an empty struct for each unit. So you might end up with, say, Scalar<Newtons> or Vec3<Meters>.

Dividing and multiplying units statically is where I've had trouble so far. I think I've found a way, but it would depend on negative trait bounds, as discussed here:

https://github.com/rust-lang/rfcs/issues/1053

Ideally, I'd like to be able to do something like this:

    let a: Scalar<Joules> = Scalar::new(2.0);
    let b: Scalar<Seconds> = Scalar::new(3.0);
    let c: Scalar<Watts> = a / b;
    // Watts is a type synonym for Over<Joules, Seconds>.
    // Other derived units would use Times<U, V>. E.g.:
    type Pascals = Times<Newton, Times<Meter, Meter>>.