Macro key 

macro_rules! key {
    ($key:expr) => { ... };
}

Available on crate features langid and locale only.

Create a literal key.

use std::str::FromStr;

use json_gettext::key;
use json_gettext::unic_langid::subtags::{Language, Region};
use json_gettext::Key;

let key = key!("en_US");

assert_eq!(Key(Language::from_str("en").unwrap(), Some(Region::from_str("US").unwrap())), key);