Enums with data as HashMap keys

Published 193d ago

Arbitrary types can be used as HashMap keys, as long as they implement the appropriate traits which can usually be auto-derived.

use std::collections::HashMap;

#[derive(Clone, PartialEq, Eq, Hash, Debug)]
enum Key {
    Position(i32, i32),
    Name(String),
    Group(Vec<Key>),
}

fn main() {
    let mut map = HashMap::new();
    map.insert(Key::Position(5, 3), 1);
    map.insert(Key::Name("Foo".into()), 2);
    map.insert(
        Key::Group(vec![Key::Position(0, 1), Key::Name("Bar".into())]),
        3,
    );
    println!("Map: {map:?}");
}