Function eval_with_instance 

pub fn eval_with_instance(
    expr: &Expr,
    env: &Env,
    config: &EvalConfig,
    instance: &WInstance,
    context_node_id: Option<u32>,
) -> Result<Literal, ExprError>

Evaluate an expression with access to an instance graph.

Graph traversal builtins (Edge, Children, HasEdge, EdgeCount, Anchor) are resolved against the provided instance. All other expressions delegate to panproto_expr::eval.

The context_node_id determines which node is the “current” node for graph traversal. Pass None to disable graph traversal.

Errors

Returns panproto_expr::ExprError on evaluation failure.