Struct Index 

pub struct Index { /* private fields */ }

Stable handle into an Arena.

An Index is Copy, cheap to pass by value, and remains valid until the element it points at is removed. Once removed, the handle becomes stale and all lookups against the arena return None (or Error::StaleIndex from fallible variants). Reusing the underlying slot under a new generation does not revive the original handle.

Layout

Index is 8 bytes (two u32s) and packs trivially into structs.

Implementations

impl Index

pub const fn slot(self) -> u32

Returns the slot number this handle points at.

Useful for diagnostics; do not use the slot number as a substitute for the handle itself — slots are reused under new generations.

pub const fn generation(self) -> u32

Returns the generation counter recorded when this handle was issued.

Trait Implementations

impl Clone for Index

fn clone(&self) -> Index

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Index

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

Formats the value using the given formatter.

impl Hash for Index

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Ord for Index

fn cmp(&self, other: &Index) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Index

fn eq(&self, other: &Index) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for Index

fn partial_cmp(&self, other: &Index) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for Index

impl Eq for Index

impl StructuralPartialEq for Index