Function to map a function over a grid while passing in the indices

gridMapWithIndices.elm

gridMapWithIndices : (Int -> Int -> a -> b) -> List (List a) -> List (List b)
gridMapWithIndices function grid = 
  let iterateColumns x y columnCount row = 
      if (x >= columnCount || row == []) then []
      else 
        function x y (head row) :: iterateColumns (x + 1) y columnCount (tail row)
        
      iterateRows y rowCount grd = 
        if (y >= rowCount) then []
        else 
         iterateColumns 0 y (length <| head grd) (head grd) :: iterateRows (y + 1) rowCount (tail grd)
  
  in iterateRows 0 (length grid) grid