Haskell Question

This tokenize function uses a given character to break up a string into a list of strings.

Fill in the missing parts, shown by a ?

tokenize ? [] = ?

tokenize n xs = tok n xs ?

where

tok n xs acc

| xs == [] = ?

| n == ? xs = ? ++ tokenize n (? xs)

| ? = tok n (? xs) (acc ++ ?)

Example output:

> tokenize ',' "fish,broccoli,cereal"

["fish","broccoli","cereal"]

Thanks