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