TypeMap

A typesafe store keyed by types and containing different types of values.

Documentation

It provides functionality similar to AnyMap, but is more flexible because it allows for key-value pairs, rather than enforcing that keys and values are the same type.

Key-value associations are defined through the Key trait, which uses an associated type parameter and trait coherence rules to enforce the invariants of TypeMap.

Example

extern crate typemap;
use typemap::{TypeMap, Key};

struct KeyType;

#[derive(Debug, PartialEq)]
struct Value(i32);

impl Key for KeyType { type Value = Value; }

#[test] fn test_pairing() {
    let mut map = TypeMap::new();
    map.insert::<KeyType>(Value(42));
    assert_eq!(*map.get::<KeyType>().unwrap(), Value(42));
}