Haskell: split a string using a substring

split-with-substring.hs

splitStr :: Eq a => [a] -> [a] -> [[a]]
splitStr sub str = split' sub str [] []
    where
    split' _   []  subacc acc = reverse (reverse subacc:acc)
    split' sub str subacc acc
        | sub `isPrefixOf` str = split' sub (drop (length sub) str) [] (reverse subacc:acc)
        | otherwise            = split' sub (tail str) (head str:subacc) acc