Span

2 min read

No import is needed.

Read the usage guide for examples and common tasks. This reference lists the public declarations for this part of the library. See Reading API signatures for parameter and result notation.

Span

A writable, bounds-checked view of a contiguous range in an array. Changes affect the original array. Spans keep their source alive, cannot be stored in heap objects, and cannot cross an await.

public ref struct Span<T>

constructor

A view of array[offset .. offset + length). Traps unless that range lies inside array; every later access relies on it.

public constructor(borrow array: T[], offset: int, length: int)

of

A span over the whole of array.

public static fun of(borrow array: T[]): Span<T>

length

Number of elements this span covers.

public get length(): int

is_empty

True when this span covers no elements.

public fun is_empty(): bool

as_read_only

The same elements, viewed read-only.

public fun as_read_only(): ReadOnlySpan<T>

this

The element at index (relative to this span, not the backing array). Traps if out of range.

public fun this[index: int]: T

this

Overwrites the element at index (relative to this span). Traps if out of range.

public fun this[index: int] = value: T

slice

Returns a view of elements from start (inclusive) to end (exclusive) that shares this span's storage. Panics unless 0 <= start <= end <= length.

public fun slice(start: int, end: int): Span<T>

slice

Returns a view from start to the end of this span. Panics unless 0 <= start <= length.

public fun slice(start: int): Span<T>

index_of

Index of the first element equal to value, or None.

public fun index_of(borrow value: T): Option<int>

contains

True when some element equals value.

public fun contains(borrow value: T): bool

sequence_equal

True when other has the same length and pairwise-equal elements.

public fun sequence_equal(other: ReadOnlySpan<T>): bool

sequence_equal

Returns whether both spans contain equal elements in the same order.

public fun sequence_equal(other: Span<T>): bool

copy_from

Copies every element of src into the start of this span. The destination must be large enough. Overlapping ranges are supported.

public fun copy_from(src: Span<T>): void

copy_from

Copies every element of src into the start of this span. The destination must be large enough. Overlapping ranges are supported.

public fun copy_from(src: Span<T>): void where T: unmanaged

copy_to

Copies every element into the start of dst. Panics if the destination is shorter. Overlapping ranges are supported.

public fun copy_to(dst: Span<T>): void

copy_to

Copies every element into the start of dst. Panics if the destination is shorter. Overlapping ranges are supported.

public fun copy_to(dst: Span<T>): void where T: unmanaged

fill

Fills every element of this span with value.

public fun fill(value: T): void

to_array

Copies every element of this span into a fresh, independently-owned array.

public fun to_array(): T[]

to_array

Copies the elements into a new array.

public fun to_array(): T[]where T: unmanaged