A hash-heap is a combination of a heap and a hashtbl that supports constant time lookup, and log(n) time removal and replacement of elements in addition to the normal heap operations.
module Hashtbl : Core_hashtbl
module Heap : Heap.Removable
module type Key = Hashtbl.Key
module type S = sig .. end
module Key : Key
type 'a t
val create : ?min_size:int -> ('a -> 'a -> int) -> 'a t
val copy : 'a t -> 'a t
val push : 'a t -> key:Key.t -> data:'a -> [ `Key_already_present | `Ok ]
val push_exn : 'a t -> key:Key.t -> data:'a -> unit
val replace : 'a t -> key:Key.t -> data:'a -> unit
val remove : 'a t -> Key.t -> unit
val mem : 'a t -> Key.t -> bool
val top : 'a t -> 'a option
val top_exn : 'a t -> 'a
val top_with_key : 'a t -> (Key.t * 'a) option
val top_with_key_exn : 'a t -> Key.t * 'a
val pop_with_key : 'a t -> (Key.t * 'a) option
val pop_with_key_exn : 'a t -> Key.t * 'a
val pop : 'a t -> 'a option
val pop_exn : 'a t -> 'a
val pop_if_with_key : 'a t -> (key:Key.t -> data:'a -> bool) -> (Key.t * 'a) option
val pop_if : 'a t -> ('a -> bool) -> 'a option
val find : 'a t -> Key.t -> 'a option
val find_pop : 'a t -> Key.t -> 'a option
val find_exn : 'a t -> Key.t -> 'a
val find_pop_exn : 'a t -> Key.t -> 'a
val iter : 'a t -> f:(key:Key.t -> data:'a -> unit) -> unit
val iter_vals : 'a t -> f:('a -> unit) -> unit
val length : 'a t -> int
module Make : 
functor (Key : Key) -> S with module Key = Key