Example
Use the lazy_static crate to create global immutable variables which are initialized at runtime. We use HashMap as a demonstration.
In Cargo.toml:
[dependencies]
lazy_static = "0.1.*"
In main.rs:
#[macro_use]
extern crate lazy_static;
lazy_static! {
static ref HASHMAP: HashMap<u32, &'static str> = {
let mut m = HashMap::new();
m.insert(0, "hello");
m.insert(1, ",");
m.insert(2, " ");
m.insert(3, "world");
m
};
static ref COUNT: usize = HASHMAP.len();
}
fn main() {
// We dereference COUNT because it's type is &usize
println!("The map has {} entries.", *COUNT);
// Here we don't dereference with * because of Deref coercions
println!("The entry for `0` is \"{}\".", HASHMAP.get(&0).unwrap());
}
