Struct GraphMut 

pub struct GraphMut<'a> {
    pub ids: &'a IdMap,
    pub syms: &'a mut Interner,
    pub labels: &'a [u32],
    pub props: ColumnsView<'a>,
    pub topo: &'a mut Topology,
    pub base_topo: Option<&'a ArchivedCsr>,
    pub edge_props: &'a mut EdgeProps,
}

Borrowed mutable view of graph state the engine writes derived edges into.

Fields

ids: &'a IdMap

syms: &'a mut Interner

labels: &'a [u32]

props: ColumnsView<'a>

topo: &'a mut Topology

Edges written since the snapshot. Reads must go through GraphMut::neighbors, not this field: on a store opened from a snapshot the overlay is empty and every edge lives in base_topo.

base_topo: Option<&'a ArchivedCsr>

The snapshot’s archived CSR, when one is open. None for a store with no snapshot, where topo already holds everything.

edge_props: &'a mut EdgeProps

Implementations

impl GraphMut<'_>

pub fn neighbors(&self, etype: u32, dir: Direction, v: u32) -> Cow<'_, [u32]>

Neighbours of v over (etype, dir), merging the snapshot base with the post-snapshot overlay and subtracting the overlay’s tombstones.

A rule that reads the graph’s shape — today only a via-hop rule, when it expands its hop — must use this rather than topo directly. Reading the overlay alone on a store opened from a snapshot returns nothing, which a via-hop rule cannot distinguish from “this source reaches no via node” and answers by retracting every edge it owns.