sig
type key = string
type data = dlemma
val mem : key -> bool
val find : key -> data
val get : key -> data option
val define : key -> data -> unit
val update : key -> data -> unit
val memoize : (key -> data) -> key -> data
val compile : (key -> data) -> key -> unit
val callback : (key -> data -> unit) -> unit
val iter : (key -> data -> unit) -> unit
val iter_sorted : (key -> data -> unit) -> unit
end