HExtlib.list_findopt (fun y i -> if y = x then Some i else None) l
with
| Some i -> i
- | None _ -> assert false
+ | None -> assert false
;;
let pos_of x t =
HExtlib.list_findopt (fun y j -> if i+1=j then Some y else None) l
with
| Some i -> i
- | None _ -> assert false)
+ | None -> assert false)
| _ -> assert false
;;