This library exports an unordered, growable map type with heap-allocated contents, written as Registry<T>. All contained values have their unique indices attributed to them at the point of insertion. Indices are freed when the items are removed.

Registries have O(1) indexing, O(1) removal and O(1) insertion.

Examples

You can explicitly create a Registry with Registry::new:

let r: Registry<i32> = Registry::new();

You can [insert] values into the registry:

let mut r = Registry::new();
let index = r.insert(3);

Removing values works in much the same way:

let mut r = Registry::new();

let index = r.insert(3);
let three = r.remove(index);

Registries also support indexing (through the Index and IndexMut traits):

let mut r = Registry::new();
let i1 = r.insert(1);
let i2 = r.insert(4);

let one = r[i1];
r[i2] = r[i2] + 5;

The Registry type also exposes a full iterator API, so it can be used just like any other Rust container.