Struct Arena

pub struct Arena<T> { /* private fields */ }

An arena holding some kind of component (e.g., type, constant, instruction, etc.) that can be referenced.

Adding new items to the arena produces a strongly-typed Handle. The arena can be indexed using the given handle to obtain a reference to the stored item.

Implementations

impl<T> Arena<T>

pub const fn new() -> Self

Create a new arena with no initial capacity allocated.

pub fn into_inner(self) -> Vec<T>

Extracts the inner vector.

pub fn len(&self) -> usize

Returns the current number of items stored in this arena.

pub fn is_empty(&self) -> bool

Returns true if the arena contains no elements.

pub fn iter(&self) -> impl DoubleEndedIterator<Item = (Handle<T>, &T)>

Returns an iterator over the items stored in this arena, returning both the item’s handle and a reference to it.

pub fn drain(&mut self) -> impl DoubleEndedIterator<Item = (Handle<T>, T, Span)>

Drains the arena, returning an iterator over the items stored.

pub fn iter_mut( &mut self, ) -> impl DoubleEndedIterator<Item = (Handle<T>, &mut T)>

Returns a iterator over the items stored in this arena, returning both the item’s handle and a mutable reference to it.

pub fn append(&mut self, value: T, span: Span) -> Handle<T>

Adds a new value to the arena, returning a typed handle.

pub fn fetch_if<F: Fn(&T) -> bool>(&self, fun: F) -> Option<Handle<T>>

Fetch a handle to an existing type.

pub fn fetch_if_or_append<F: Fn(&T, &T) -> bool>( &mut self, value: T, span: Span, fun: F, ) -> Handle<T>

Adds a value with a custom check for uniqueness: returns a handle pointing to an existing element if the check succeeds, or adds a new element otherwise.

pub fn fetch_or_append(&mut self, value: T, span: Span) -> Handle<T>

where T: PartialEq,

Adds a value with a check for uniqueness, where the check is plain comparison.

pub fn try_get(&self, handle: Handle<T>) -> Result<&T, BadHandle>

pub fn get_mut(&mut self, handle: Handle<T>) -> &mut T

Get a mutable reference to an element in the arena.

pub fn range_from(&self, old_length: usize) -> Range<T>

Get the range of handles from a particular number of elements to the end.

pub fn clear(&mut self)

Clears the arena keeping all allocations

pub fn get_span(&self, handle: Handle<T>) -> Span

pub fn check_contains_handle(&self, handle: Handle<T>) -> Result<(), BadHandle>

Assert that handle is valid for this arena.

pub fn check_contains_range( &self, range: &Range<T>, ) -> Result<(), BadRangeError>

Assert that range is valid for this arena.

Trait Implementations

impl<T: Clone> Clone for Arena<T>

fn clone(&self) -> Arena<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for Arena<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Default for Arena<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> Index<Handle<T>> for Arena<T>

type Output = T

The returned type after indexing.

fn index(&self, handle: Handle<T>) -> &T

Performs the indexing (container[index]) operation.

impl<T> Index<Range<T>> for Arena<T>

type Output = [T]

The returned type after indexing.

fn index(&self, range: Range<T>) -> &[T]

Performs the indexing (container[index]) operation.

impl<T> IndexMut<Handle<T>> for Arena<T>

fn index_mut(&mut self, handle: Handle<T>) -> &mut T

Performs the mutable indexing (container[index]) operation.