Unicode character composition and decomposition utilities as described in Unicode Standard Annex #15.

extern crate unicode_normalization;

use unicode_normalization::char::compose;
use unicode_normalization::str::UnicodeNormalization;

fn main() {
    assert_eq!(compose('A','\u{30a}'), Some('Å'));
    
    let s = "ÅΩ";
    let c = UnicodeNormalization::nfc_chars(s).collect::<String>();
    assert_eq!(c, "ÅΩ");
}

crates.io

You can use this package in your project by adding the following to your Cargo.toml:

[dependencies]
unicode-normalization = "0.0.3"