Functor Strongly_connected_components.Make

module Make: 
functor (Id : Identifiable.S) -> S with module Id := Id
Parameters:
Id : Identifiable.S

module Id: Identifiable.S 
type directed_graph = Id.Set.t Id.Map.t 
If (a -> set) belongs to the map, it means that there are edges from a to every element of set. It is assumed that no edge points to a vertex not represented in the map.
type component = 
| Has_loop of Id.t list
| No_loop of Id.t
val connected_components_sorted_from_roots_to_leaf : directed_graph ->
component array
val component_graph : directed_graph ->
(component * int list) array