Struct LambdaEdges 

pub struct LambdaEdges<V> { /* private fields */ }

Identity-keyed store of per-edge Λ decoration slots for one causal graph.

Keys are (source, target) node-index pairs — the intrinsic identity of a directed edge in the graph — so which Λ applies to which input of a join is independent of any enumeration order. Absent key = identity Λ (see LambdaEdges::apply).

Implementations

impl<V> LambdaEdges<V>

pub fn new() -> Self

Creates an empty decoration store: every edge is the identity Λ.

pub fn insert( &mut self, source: usize, target: usize, lambda: EdgeLambdaFn<V>, ) -> Option<EdgeLambdaFn<V>>

Sets the Λ slot for the edge source -> target, returning the previously stored Λ if the slot was already decorated.

pub fn with_lambda( self, source: usize, target: usize, lambda: EdgeLambdaFn<V>, ) -> Self

Builder form of LambdaEdges::insert.

pub fn get(&self, source: usize, target: usize) -> Option<EdgeLambdaFn<V>>

Looks up the Λ slot of the edge source -> target by its intrinsic identity. None means the edge is undecorated (identity Λ).

pub fn apply(&self, source: usize, target: usize, value: V) -> V

Applies the edge’s Λ to a value: the stored transform if the edge is decorated, the identity otherwise — the “undecorated edge behaves as the identity Λ” contract.

pub fn len(&self) -> usize

Number of decorated edges.

pub fn is_empty(&self) -> bool

True when no edge is decorated (the whole graph is identity-Λ).

Trait Implementations

impl<V> Clone for LambdaEdges<V>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<V> Debug for LambdaEdges<V>

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

Formats the value using the given formatter.

impl<V> Default for LambdaEdges<V>

fn default() -> Self

Returns the “default value” for a type.