Crate generic_array
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This crate implements a structure that can be used as a generic array type.
**Requires minumum Rust version of 1.65.0
Documentation on GH Pages may be required to view certain types on foreign crates.
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:
struct Foo<N> {
data: [i32; N],
}
Since 1.51, the below syntax is valid:
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:
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:
use generic_array::{GenericArray, ArrayLength};
struct Foo<N: ArrayLength> {
data: GenericArray<i32, N>
}
trait Bar {
type LEN: ArrayLength;
fn bar(&self) -> Foo<Self::LEN>;
}
The ArrayLength
trait is implemented for
unsigned integer types from
typenum. For example, GenericArray<T, U5>
would work almost like [T; 5]
:
use generic_array::typenum::U5;
struct Foo<T, N: ArrayLength> {
data: GenericArray<T, N>
}
let foo = Foo::<i32, U5> { data: GenericArray::default() };
The arr!
macro is provided to allow easier creation of literal arrays, as shown below:
let array = arr![1, 2, 3];
// array: GenericArray<i32, typenum::U3>
assert_eq!(array[2], 3);
§Feature flags
[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]>
"faster-hex" # Enables internal use of the `faster-hex` crate for faster hex encoding via SIMD
]
Re-exports§
pub extern crate typenum;
Modules§
- Functional programming with generic sequences
- Useful traits for manipulating sequences of data stored in
GenericArray
s
Macros§
- Macro allowing for easy construction of Generic Arrays.
- box_arr
alloc
Likearr!
, but returns aBox<GenericArray<T, N>>
Structs§
- Struct representing a generic array -
GenericArray<T, N>
works like[T; N]
- An iterator that moves out of a
GenericArray
- Error for
TryFrom
andtry_from_iter
Traits§
- Trait used to define the number of elements in a
GenericArray
. - Implemented for types which can have an associated
ArrayLength
, such asConst<N>
for use with const-generics.
Type Aliases§
- Associated
ArrayLength
for oneConst<N>