Util.DataV
Create a vertex type with some data attached to it
module L : sig ... end
module V : Sig.COMPARABLE
type data = L.t
and label = V.t
and t = data ref * V.t
val compare : t -> t -> int
val hash : t -> int
val equal : t -> t -> bool
val create : data -> V.t -> t
val label : t -> V.t
val data : t -> data
val set_data : t -> data -> unit