listCount : (a -> Bool) -> List a -> Int
listCount test list =
    list
        |> List.filter test
        |> List.length


listAll : (a -> Bool) -> List a -> Bool
listAll test list =
    let
        passed =
            list
                |> listCount test
    in
        passed == List.length list


listAny : (a -> Bool) -> List a -> Bool
listAny test list =
    let
        numElements =
            listCount test list
    in
        numElements > 0


listNone : (a -> Bool) -> List a -> Bool
listNone test list =
    not (listAny test list)