val set_new_sorts: (int -> 'a) -> string list -> 'a
-val get_sort: (string option -> 'a) -> int -> 'a
+val get_sort: (unit -> 'a) -> (string -> 'a) -> int -> 'a
-val graph_of_string: (graph option -> 'a) -> string -> 'a
+val graph_of_string: (unit -> 'a) -> (graph -> 'a) -> string -> 'a
val string_of_graph: (string -> 'a) -> graph -> 'a
val apply: (int -> 'a) -> graph -> int -> 'a
-
-val graph: graph ref