list of options to option list

OptionLists.fsx

let optionList l = 
    let rec bindList xs acc =
        match xs with
        | [] -> Some acc
        | h::t -> h |> Option.bind (fun x -> bindList t (x::acc))
    bindList l []

module Option = 
    let map2 f a b =
        a |> Option.bind (fun a' -> b |> Option.map (fun b' -> f a' b')) 

let optionList2 = List.fold (Option.map2 (fun acc x -> x::acc)) (Some []) >> Option.map List.rev

let res1 : int list option = [Some 1; Some 2] |> optionList2 
let res2 : int list option = [Some 1; None] |> optionList2