new #rustlang crate drop: iddqd! ID-based maps where keys are borrowed from values. Four maps are included: IdOrdMap, IdHashMap, a bijective (1:1) BiHashMap and a trijective (1:1:1) TriHashMap.
At Oxide we've found this pattern to be extraordinarily useful. iddqd is no-std compatible, too!
![use iddqd::{IdOrdMap, IdOrdItem, id_upcast};
#[derive(Debug)]
struct User {
name: String,
age: u8,
}
// Implement IdOrdItem so the map knows how to get the key from the value.
impl IdOrdItem for User {
// The key type can borrow from the value.
type Key<'a> = &'a str;
fn key(&self) -> Self::Key<'_> {
&self.name
}
id_upcast!();
}
let mut users = IdOrdMap::<User>::new();
// You must pick an insertion behavior. insert_unique returns an error if
// the key already exists.
users.insert_unique(User { name: "Alice".to_string(), age: 30 }).unwrap();
users.insert_unique(User { name: "Bob".to_string(), age: 35 }).unwrap();
// Lookup by name:
assert_eq!(users.get("Alice").unwrap().age, 30);
assert_eq!(users.get("Bob").unwrap().age, 35);
// Iterate over users:
for user in &users {
println!("User {}: {}", user.name, user.age);
}](https://fedi.ml/photo/preview/640/670240 "use iddqd::{IdOrdMap, IdOrdItem, id_upcast};
#[derive(Debug)]
struct User {
name: String,
age: u8,
}
// Implement IdOrdItem so the map knows how to get the key from the value.
impl IdOrdItem for User {
// The key type can borrow from the value.
type Key<'a> = &'a str;
fn key(&self) -> Self::Key<'_> {
&self.name
}
id_upcast!();
}
let mut users = IdOrdMap::<User>::new();
// You must pick an insertion behavior. insert_unique returns an error if
// the key already exists.
users.insert_unique(User { name: \"Alice\".to_string(), age: 30 }).unwrap();
users.insert_unique(User { name: \"Bob\".to_string(), age: 35 }).unwrap();
// Lookup by name:
assert_eq!(users.get(\"Alice\").unwrap().age, 30);
assert_eq!(users.get(\"Bob\").unwrap().age, 35);
// Iterate over users:
for user in &users {
println!(\"User {}: {}\", user.name, user.age);
}")