Trait generic_array::ArrayLength
source · pub unsafe trait ArrayLength: Unsigned + 'static {
type ArrayType<T>: Sealed;
}
Expand description
Trait used to define the number of elements in a GenericArray
.
ArrayLength
is a superset of typenum::Unsigned
.
Consider N: ArrayLength
to be equivalent to const N: usize
fn foo<N: ArrayLength>(arr: GenericArray<i32, N>) -> i32 {
arr.iter().sum()
}
is equivalent to:
fn foo<const N: usize>(arr: [i32; N]) -> i32 {
arr.iter().sum()
}
§Safety
This trait is effectively sealed due to only being allowed on Unsigned
types,
and therefore cannot be implemented in user code.
Required Associated Types§
sourcetype ArrayType<T>: Sealed
type ArrayType<T>: Sealed
Associated type representing the underlying contiguous memory that constitutes an array with the given number of elements.
This is an implementation detail, but is required to be public in cases where certain attributes
of the inner type of GenericArray
cannot be proven, such as Copy
bounds.
Copy
example:
struct MyType<N: ArrayLength> {
data: GenericArray<f32, N>,
}
impl<N: ArrayLength> Clone for MyType<N> where N::ArrayType<f32>: Copy {
fn clone(&self) -> Self { MyType { ..*self } }
}
impl<N: ArrayLength> Copy for MyType<N> where N::ArrayType<f32>: Copy {}
Alternatively, using the entire GenericArray<f32, N>
type as the bounds works:
ⓘ
where GenericArray<f32, N>: Copy
Object Safety§
This trait is not object safe.