Typenum

Typenum is a Rust library for type-level numbers evaluated at compile time. It currently supports bits, unsigned integers, and signed integers.

Typenum depends only on libcore, and so is suitable for use on any platform!

For the full documentation, go here.

Here is a trivial example of its use:

use typenum::{Sum, Exp, Integer, N2, P3, P4};

type X = Sum<P3, P4>;
assert_eq!(<X as Integer>::to_i32(), 7);

type Y = Exp<N2, P3>;
assert_eq!(<Y as Integer>::to_i32(), -8);

For a non-trivial example of its use, see one of the crates that depends on it. The full list is here. Of note are dimensioned which does compile-time type checking for arbitrary unit systems and generic-array which provides arrays whose length you can generically refer to.