README.md
1[](https://crates.io/crates/generic-array)
2[](https://travis-ci.org/fizyk20/generic-array)
3# generic-array
4
5This crate implements generic array types for Rust.
6
7[Documentation](http://fizyk20.github.io/generic-array/generic_array/)
8
9## Usage
10
11The Rust arrays `[T; N]` are problematic in that they can't be used generically with respect to `N`, so for example this won't work:
12
13```rust
14struct Foo<N> {
15 data: [i32; N]
16}
17```
18
19**generic-array** defines a new trait `ArrayLength<T>` and a struct `GenericArray<T, N: ArrayLength<T>>`, which let the above be implemented as:
20
21```rust
22struct Foo<N: ArrayLength<i32>> {
23 data: GenericArray<i32, N>
24}
25```
26
27To actually define a type implementing `ArrayLength`, you can use unsigned integer types defined in [typenum](https://github.com/paholg/typenum) crate - for example, `GenericArray<T, U5>` would work almost like `[T; 5]` :)
28
29In version 0.1.1 an `arr!` macro was introduced, allowing for creation of arrays as shown below:
30
31```rust
32let array = arr![u32; 1, 2, 3];
33assert_eq!(array[2], 3);
34```
35
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