(* Finds the zero based index of the first element that satisfies a predicate*)
val list_index: ('a -> bool) -> 'a list -> (int * 'a) option
val sharing_map: ('a -> 'a) -> 'a list -> 'a list
+val sharing_map_acc:
+ ('acc -> 'a -> 'acc * 'a) -> 'acc -> 'a list -> 'acc * 'a list
(* Iters in parallel on two lists until the first list is empty.
The second one can be shorter and is padded with a default value.
This function cannot fail. *)