It is now possible to easily replicate this crate's functionality in Rust's standard library with [`std::sync::OnceLock`](https://doc.rust-lang.org/std/sync/struct.OnceLock.html). The example above could be also be written as:

use std::collections::HashMap;

use std::sync::OnceLock;

fn hashmap() -> &'static HashMap<u32, &'static str> {

static HASHMAP: OnceLock<HashMap<u32, &str>> = OnceLock::new();

HASHMAP.get_or_init(|| {

let mut m = HashMap::new();

m.insert(0, "foo");

m.insert(1, "bar");

m.insert(2, "baz");

m

})

}

fn main() {

// First access to `HASHMAP` initializes it

println!("The entry for `0` is \"{}\".", hashmap().get(&0).unwrap());

// Any further access to `HASHMAP` just returns the computed value

println!("The entry for `1` is \"{}\".", hashmap().get(&1).unwrap());

}