Struct ConversationGraph 

pub struct ConversationGraph { /* private fields */ }

Directed acyclic graph of conversation nodes.

Invariants

• Every NodeId returned by add_node is unique and stable for the lifetime of the graph.
• add_edge rejects any edge that would create a cycle.
• linearize always returns a valid topological ordering.

Implementations

impl ConversationGraph

pub fn new() -> Self

Create an empty graph.

pub fn add_node( &mut self, role: impl Into<String>, content: impl Into<String>, tokens: usize, ) -> NodeId

Add a new node to the graph and return its NodeId.

pub fn add_edge(&mut self, from: NodeId, to: NodeId) -> Result<(), GraphError>

Add a directed edge from -> to.

Errors

• GraphError::NodeNotFound if either from or to is unknown.
• GraphError::InvalidEdge if from == to (self-loop).
• GraphError::CycleDetected if the edge would create a cycle.

pub fn branch_from(&mut self, node_id: NodeId) -> Result<NodeId, GraphError>

Clone the node at node_id, attach the clone as a child, and return the clone’s NodeId.

Errors

Returns GraphError::NodeNotFound if node_id is unknown.

pub fn merge_paths( &mut self, path_a: &[NodeId], path_b: &[NodeId], ) -> Result<NodeId, GraphError>

Create a merge node that references both path_a and path_b.

The merge node has role "merge" and empty content. Edges are added from the last node of each path to the merge node.

Errors

• GraphError::InvalidEdge if either path is empty.
• Propagates errors from add_edge.

pub fn linearize(&self, root: NodeId) -> Result<Vec<NodeId>, GraphError>

Topological sort of all nodes reachable from root using Kahn’s algorithm.

Returns nodes in breadth-first topological order.

Errors

• GraphError::NodeNotFound if root is unknown.
• GraphError::CycleDetected if the reachable subgraph is not a DAG (should not happen if all edges were added through add_edge).

pub fn path_tokens(&self, path: &[NodeId]) -> usize

Sum the token counts of all nodes in path.

Unknown node IDs are silently skipped.

pub fn get_node(&self, id: NodeId) -> Option<&ConversationNode>

Borrow the node for id, if it exists.

Trait Implementations

impl Debug for ConversationGraph

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

Formats the value using the given formatter.

impl Default for ConversationGraph

fn default() -> ConversationGraph

Returns the “default value” for a type.