Struct Elem 

pub struct Elem<T>
where
    T: 'static,
{ /* private fields */ }

One element of a keyed store, addressed by a key that survives reordering.

Implementations

impl<T> Elem<T>

where T: Identified + 'static,

pub fn key(self) -> u64

The path handle this element addresses: the raw form of Elem::model_id.

pub fn model_id(self) -> ModelId<T>

The element’s typed id. (Named to stay clear of the id field accessor an inherent id() would shadow on every model that has one.)

pub fn exists(self) -> bool

Whether the row is (still) present. Tracked, so a guard re-runs when the row is deleted or comes back. This is the deletion story: reads of a gone row return the field’s Default, and this is the one signal a page needs to degrade instead.

Trait Implementations

impl<T> Clone for Elem<T>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Copy for Elem<T>

impl<T> SelectionKey for Elem<T>

where T: Identified + 'static,

A store row names itself by its key, so a store list binds List::selection.

fn selection_key(&self) -> u64

impl<T> Source<T> for Elem<T>

where T: Identified + 'static,

fn path(self) -> Path

The path this source occupies. Implementations revalidate against the interner, so the result is always current.

fn node(self) -> NodeId

This source’s interned id, so a child can be built with no lookup of its own.

fn components(self, out: &mut Vec<u64>)

The path as plain components, resolved by walking the handle chain rather than the interner. This is what crosses a thread boundary: a worker names what it changed with components, and the main thread re-establishes them on its own side when it announces.

fn with_value_untracked<R>(self, f: impl FnOnce(Option<&T>) -> R) -> R

fn update_value(self, f: impl FnOnce(&mut T)) -> bool

Returns false when the value is gone (a deleted row), in which case nothing is announced either.

fn bump_version(self)

const DYNAMIC: bool = false

Whether this source’s location can change over the handle’s lifetime: a recycled list slot whose current row rotates. Fields projected from a dynamic source resolve their path through the source on every operation instead of trusting the one cached at projection time, and their tracked reads also run Source::track_extra.

fn track_extra(self)

Extra tracking a projected field’s tracked reads perform. A dynamic source tracks its own rebind signal here, so a control bound at build follows the slot to its next row.

fn with<R>(self, f: impl FnOnce(Option<&T>) -> R) -> R

Tracked read of the whole value: the coarse subscription.