TypeMap

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

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

#[deriving(Show, PartialEq)]
struct KeyType;

#[deriving(Show, PartialEq)]
struct Value(i32);

impl Key for KeyType { type Value = Value; }

#[test] fn test_pairing() {
    let mut map = TypeMap::new();
    map.insert::<KeyType>(Value(12));
    assert_eq!(*map.find::<KeyType>().unwrap(), Value(12);
}

lib.rs:

A type-based key value store where one value type is allowed for each key.