pub trait TriHashItem {
type K1<'a>: Eq + Hash
where Self: 'a;
type K2<'a>: Eq + Hash
where Self: 'a;
type K3<'a>: Eq + Hash
where Self: 'a;
// Required methods
fn key1(&self) -> Self::K1<'_>;
fn key2(&self) -> Self::K2<'_>;
fn key3(&self) -> Self::K3<'_>;
fn upcast_key1<'short, 'long: 'short>(
long: Self::K1<'long>,
) -> Self::K1<'short>;
fn upcast_key2<'short, 'long: 'short>(
long: Self::K2<'long>,
) -> Self::K2<'short>;
fn upcast_key3<'short, 'long: 'short>(
long: Self::K3<'long>,
) -> Self::K3<'short>;
}Expand description
An item in a TriHashMap.
This trait is used to define the keys.
§Examples
use iddqd::{TriHashItem, TriHashMap, tri_upcast};
// Define a struct with three keys.
#[derive(Debug, PartialEq, Eq, Hash)]
struct Person {
id: u32,
name: String,
email: String,
}
// Implement TriHashItem for the struct.
impl TriHashItem for Person {
type K1<'a> = u32;
type K2<'a> = &'a str;
type K3<'a> = &'a str;
fn key1(&self) -> Self::K1<'_> {
self.id
}
fn key2(&self) -> Self::K2<'_> {
&self.name
}
fn key3(&self) -> Self::K3<'_> {
&self.email
}
tri_upcast!();
}
// Create a TriHashMap and insert items.
let mut map = TriHashMap::new();
map.insert_unique(Person {
id: 1,
name: "Alice".to_string(),
email: "alice@example.com".to_string(),
})
.unwrap();
map.insert_unique(Person {
id: 2,
name: "Bob".to_string(),
email: "bob@example.com".to_string(),
})
.unwrap();Required Associated Types§
Required Methods§
Sourcefn upcast_key1<'short, 'long: 'short>(long: Self::K1<'long>) -> Self::K1<'short>
fn upcast_key1<'short, 'long: 'short>(long: Self::K1<'long>) -> Self::K1<'short>
Upcasts the first key to a shorter lifetime, in effect asserting that
the lifetime 'a on TriHashItem::K1 is covariant.
Typically implemented via the tri_upcast macro.
Sourcefn upcast_key2<'short, 'long: 'short>(long: Self::K2<'long>) -> Self::K2<'short>
fn upcast_key2<'short, 'long: 'short>(long: Self::K2<'long>) -> Self::K2<'short>
Upcasts the second key to a shorter lifetime, in effect asserting that
the lifetime 'a on TriHashItem::K2 is covariant.
Typically implemented via the tri_upcast macro.
Sourcefn upcast_key3<'short, 'long: 'short>(long: Self::K3<'long>) -> Self::K3<'short>
fn upcast_key3<'short, 'long: 'short>(long: Self::K3<'long>) -> Self::K3<'short>
Upcasts the third key to a shorter lifetime, in effect asserting that
the lifetime 'a on TriHashItem::K3 is covariant.
Typically implemented via the tri_upcast macro.
Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.