type cursor_result = {cursor_id: string; rows: Tuple.materialized list; has_more: bool}

(** A Transition delta names every multigroup that the statement touched and the
    updated value for each. Most statements yield a single-element list;
    VCL/SCL/ICL statements may touch more than one. *)
type transition_delta = (string * Management.Multigroup.multigroup) list

type result =
  | Query of Relation.relation
  | Transition of transition_delta
  | Cursor of cursor_result
  | SessionSwitch of string
  | CreateMultigroup of string