Type Aliases

A type alias creates a name for another type. The two types can be used interchangeably.

enum CarryableConcreteItem {
    Left,
    Right,
}

type Item = CarryableConcreteItem;

// Aliases are more useful with long, complex types:
use std::cell::RefCell;
use std::sync::{Arc, RwLock};
type PlayerInventory = RwLock<Vec<Arc<RefCell<Item>>>>;
This slide should take about 2 minutes.

  • A newtype is often a better alternative since it creates a distinct type. Prefer struct InventoryCount(usize) to type InventoryCount = usize.

  • C programmers will recognize this as similar to a typedef.