Macro tri_hash_map

macro_rules! tri_hash_map {
    ($($item:expr,)+) => { ... };
    ($($item:expr),*) => { ... };
    ($H:ty; $($item:expr,)+) => { ... };
    ($H:ty; $($item:expr),*) => { ... };
}

Creates a TriHashMap from a list of items.

An optional BuildHasher that implements Default can be provided as the first argument, followed by a semicolon.

Panics

Panics if the list of items has duplicate keys. For better error handling, the item is required to implement Debug.

Examples

use iddqd::{TriHashItem, tri_hash_map, tri_upcast};

#[derive(Debug)]
struct Person {
    id: u32,
    name: String,
    email: String,
}

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!();
}

let map = tri_hash_map! {
    Person { id: 1, name: "Alice".to_string(), email: "alice@example.com".to_string() },
    Person { id: 2, name: "Bob".to_string(), email: "bob@example.com".to_string() },
};
assert_eq!(map.get1(&1).unwrap().name, "Alice");
assert_eq!(map.get2("Bob").unwrap().id, 2);
assert_eq!(map.get3("alice@example.com").unwrap().name, "Alice");

// With a custom hasher:
let map = tri_hash_map! {
    foldhash::quality::RandomState;
    Person { id: 3, name: "Charlie".to_string(), email: "charlie@example.com".to_string() },
    Person { id: 4, name: "Eve".to_string(), email: "eve@example.com".to_string() },
};
assert_eq!(map.get1(&3).unwrap().name, "Charlie");
assert_eq!(map.get2("Eve").unwrap().id, 4);