Trait IdHashItem 

pub trait IdHashItem {
    type Key<'a>: Eq + Hash
       where Self: 'a;

    // Required methods
    fn key(&self) -> Self::Key<'_>;
    fn upcast_key<'short, 'long: 'short>(
        long: Self::Key<'long>,
    ) -> Self::Key<'short>;
}

An element stored in an IdHashMap.

This trait is used to define the key type for the map.

Examples

use iddqd::{IdHashItem, IdHashMap, id_upcast};

// Define a struct with a key.
#[derive(Debug, PartialEq, Eq, Hash)]
struct MyItem {
    id: String,
    value: u32,
}

// Implement IdHashItem for the struct.
impl IdHashItem for MyItem {
    // Keys can borrow from the item.
    type Key<'a> = &'a str;

    fn key(&self) -> Self::Key<'_> {
        &self.id
    }

    id_upcast!();
}

// Create an IdHashMap and insert items.
let mut map = IdHashMap::new();
map.insert_unique(MyItem { id: "foo".to_string(), value: 42 }).unwrap();
map.insert_unique(MyItem { id: "bar".to_string(), value: 20 }).unwrap();

Required Associated Types

type Key<'a>: Eq + Hash where Self: 'a

The key type.

Required Methods

fn key(&self) -> Self::Key<'_>

Retrieves the key.

fn upcast_key<'short, 'long: 'short>( long: Self::Key<'long>, ) -> Self::Key<'short>

Upcasts the key to a shorter lifetime, in effect asserting that the lifetime 'a on IdHashItem::Key is covariant.

Typically implemented via the id_upcast macro.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<'b, T: 'b + ?Sized + IdHashItem> IdHashItem for &'b T

type Key<'a> = <T as IdHashItem>::Key<'a> where Self: 'a

fn key(&self) -> Self::Key<'_>

fn upcast_key<'short, 'long: 'short>( long: Self::Key<'long>, ) -> Self::Key<'short>

where Self: 'long,

impl<'b, T: 'b + ?Sized + IdHashItem> IdHashItem for &'b mut T

type Key<'a> = <T as IdHashItem>::Key<'a> where Self: 'a

fn key(&self) -> Self::Key<'_>

fn upcast_key<'short, 'long: 'short>( long: Self::Key<'long>, ) -> Self::Key<'short>

where Self: 'long,

impl<T: ?Sized + IdHashItem> IdHashItem for Arc<T>

type Key<'a> = <T as IdHashItem>::Key<'a> where Self: 'a

fn key(&self) -> Self::Key<'_>

fn upcast_key<'short, 'long: 'short>( long: Self::Key<'long>, ) -> Self::Key<'short>

impl<T: ?Sized + IdHashItem> IdHashItem for Box<T>

type Key<'a> = <T as IdHashItem>::Key<'a> where Self: 'a

fn key(&self) -> Self::Key<'_>

fn upcast_key<'short, 'long: 'short>( long: Self::Key<'long>, ) -> Self::Key<'short>

impl<T: ?Sized + IdHashItem> IdHashItem for Rc<T>

type Key<'a> = <T as IdHashItem>::Key<'a> where Self: 'a

fn key(&self) -> Self::Key<'_>

fn upcast_key<'short, 'long: 'short>( long: Self::Key<'long>, ) -> Self::Key<'short>

Implementors

impl<T: BiHashItem> IdHashItem for iddqd::bi_hash_map::ByK1<T>

Available on crate feature daft only.

type Key<'a> = <T as BiHashItem>::K1<'a> where T: 'a

impl<T: BiHashItem> IdHashItem for iddqd::bi_hash_map::ByK2<T>

Available on crate feature daft only.

type Key<'a> = <T as BiHashItem>::K2<'a> where T: 'a

impl<T: IdHashItem> IdHashItem for IdLeaf<T>

Available on crate feature daft only.

type Key<'a> = <T as IdHashItem>::Key<'a> where T: 'a

impl<T: TriHashItem> IdHashItem for iddqd::tri_hash_map::ByK1<T>

Available on crate feature daft only.

type Key<'a> = <T as TriHashItem>::K1<'a> where T: 'a

impl<T: TriHashItem> IdHashItem for iddqd::tri_hash_map::ByK2<T>

Available on crate feature daft only.

type Key<'a> = <T as TriHashItem>::K2<'a> where T: 'a

impl<T: TriHashItem> IdHashItem for ByK3<T>

Available on crate feature daft only.

type Key<'a> = <T as TriHashItem>::K3<'a> where T: 'a