generic-array

This crate implements generic array types for Rust.

**Requires minumum Rust version of 1.65.0

Documentation

Usage

Before Rust 1.51, arrays [T; N] were problematic in that they couldn't be generic with respect to the length N, so this wouldn't work:

rust struct Foo<N> { data: [i32; N], }

Since 1.51, the below syntax is valid:

rust struct Foo<const N: usize> { data: [i32; N], }

However, the const-generics we have as of writing this are still the minimum-viable product (min_const_generics), so many situations still result in errors, such as this example:

```rust trait Bar { const LEN: usize;

// Error: cannot perform const operation using `Self`
fn bar(&self) -> Foo<{ Self::LEN }>;

} ```

generic-array defines a new trait ArrayLength and a struct GenericArray<T, N: ArrayLength>, which lets the above be implemented as:

```rust struct Foo { data: GenericArray }

trait Bar { type LEN: ArrayLength; fn bar(&self) -> Foo; } ```

The ArrayLength trait is implemented by default for unsigned integer types from typenum crate:

```rust use generic_array::typenum::U5;

struct Foo { data: GenericArray }

let foo = Foo::{data: GenericArray::default()}; ```

For example, GenericArray<T, U5> would work almost like [T; 5]:

```rust use generic_array::typenum::U5;

struct Foo { data: GenericArray }

let foo = Foo::{data: GenericArray::default()}; ```

The arr! macro is provided to allow easier creation of literal arrays, as shown below:

rust let array = arr![1, 2, 3]; // array: GenericArray<i32, typenum::U3> assert_eq!(array[2], 3);

Feature flags

toml [dependencies.generic-array] features = [ "more_lengths", # Expands From/Into implementation for more array lengths "serde", # Serialize/Deserialize implementation "zeroize", # Zeroize implementation for setting array elements to zero "const-default", # Compile-time const default value support via trait "alloc" # Enables From/TryFrom implementations between GenericArray and Vec<T>/Box<[T]> ]