FoldLeftVsRight.ml

ListLabels.fold_left;;
ListLabels.fold_left ~f: (fun x y -> x - y) ~init:0 [1; 2; 3];;

ListLabels.fold_right;;
ListLabels.fold_right ~f: (fun y x -> x - y) ~init:0 [1; 2; 3];;

let rec fold_left ~op: (f: acc:'a -> elt:'b -> )