Standard ML Functional programming:

(b) Using the function map below: fun map (f,xs) = case xs of [] => [] |x::xs' => (f x) :: map (f, xs'). define a function called listify that turns a list of elements into lists of list of ele- ments. Each element in the input list is converted to a list of one element in the output (their positions are preserved). Example: listify [1,9,3] returns [[1], [9], [3]] (b) Using the function map below: fun map (f,xs) = case xs of [] => [] |x::xs' => (f x) :: map (f, xs'). define a function called listify that turns a list of elements into lists of list of ele- ments. Each element in the input list is converted to a list of one element in the output (their positions are preserved). Example: listify [1,9,3] returns [[1], [9], [3]]