itlist2

Lib.itlist2 : ('a -> 'b -> 'c -> 'c) -> 'a list -> 'b list -> 'c -> 'c

Applies a function to corresponding elements of 2 lists.

itlist2 f [x1,...,xn] [y1,...,yn] z returns

   f x1 y1 (f x2 y2 ... (f xn yn z)...)

An invocation itlist2 f list1 list2 b returns b if list1 and list2 are empty.

Failure

Fails if the two lists are of different lengths, or if one of the applications of f fails.

Example

- itlist2 (fn x => fn y => fn z => (x,y)::z) [1,2] [3,4] [];
> val it = [(1,3), (2,4)] : (int * int) list

See also

Lib.itlist, Lib.rev_itlist, Lib.rev_itlist2, Lib.end_itlist