63 lines
1.7 KiB
Markdown
63 lines
1.7 KiB
Markdown
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[](https://crates.io/crates/generic-array)
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[](https://travis-ci.org/fizyk20/generic-array)
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# 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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[Documentation](http://fizyk20.github.io/generic-array/generic_array/)
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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
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struct Foo<N> {
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data: [i32; N]
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}
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```
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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
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struct Foo<N: ArrayLength<i32>> {
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data: GenericArray<i32, N>
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}
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```
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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
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use generic_array::typenum::U5;
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struct Foo<N: ArrayLength<i32>> {
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data: GenericArray<i32, N>
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}
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fn main() {
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let foo = Foo::<U5>{data: GenericArray::default()};
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}
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```
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For example, `GenericArray<T, U5>` would work almost like `[T; 5]`:
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```rust
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use generic_array::typenum::U5;
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struct Foo<T, N: ArrayLength<T>> {
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data: GenericArray<T, N>
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}
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fn main() {
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let foo = Foo::<i32, U5>{data: GenericArray::default()};
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}
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```
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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
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let array = arr![u32; 1, 2, 3];
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assert_eq!(array[2], 3);
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```
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