rust-numerals 
This is a library for various numeric systems, including ancient, modern, and just plain strange.
Although the Roman module is likely to be the most popular, I maintain an interest in the others, so they're all packaged as one!
View the Rustdoc
Installation
This library uses Cargo. Just add numerals as a
dependency in your Cargo.toml:
[]
= "*"
or
[]
= "https://github.com/ogham/rust-numerals.git"
Roman
use Roman;
let string = format!;
assert_eq!;