[](https://crates.io/crates/generic-array)
[](https://travis-ci.org/fizyk20/generic-array)
# generic-array
This crate implements generic array types for Rust.
**Requires minumum Rust version of 1.36.0, or 1.41.0 for `From<[T; N]>` implementations**
[Documentation](http://fizyk20.github.io/generic-array/generic_array/)
## Usage
The 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:
```rust
struct Foo<N> {
data: [i32; N]
}
```
**generic-array** defines a new trait `ArrayLength<T>` and a struct `GenericArray<T, N: ArrayLength<T>>`, which let the above be implemented as:
```rust
struct Foo<N: ArrayLength<i32>> {
data: GenericArray<i32, N>
}
```
The `ArrayLength<T>` trait is implemented by default for [unsigned integer types](http://fizyk20.github.io/generic-array/typenum/uint/index.html) from [typenum](http://fizyk20.github.io/generic-array/typenum/index.html) crate:
```rust
use generic_array::typenum::U5;
struct Foo<N: ArrayLength<i32>> {
data: GenericArray<i32, N>
}
fn main() {
let foo = Foo::<U5>{data: GenericArray::default()};
}
```
For example, `GenericArray<T, U5>` would work almost like `[T; 5]`:
```rust
use generic_array::typenum::U5;
struct Foo<T, N: ArrayLength<T>> {
data: GenericArray<T, N>
}
fn main() {
let foo = Foo::<i32, U5>{data: GenericArray::default()};
}
```
In version 0.1.1 an `arr!` macro was introduced, allowing for creation of arrays as shown below:
```rust
let array = arr![u32; 1, 2, 3];
assert_eq!(array[2], 3);
```