MapAll Function in Elm. Applies a 2-ary function to each element in a list to each element in a list

MapAll.elm

mapAll : (a -> a -> a) -> List a -> List (List a)
mapAll f list = 
  let innerMapAll f tempList = 
    case tempList of 
      [] -> []
      x :: xs -> map (f x) list :: innerMapAll f xs 
  in innerMapAll f list