string.hs

module String where
import Data.List

notThe :: String -> Maybe String
notThe = wrapper . unwords . filter (\x -> x /="the" && x /="The") . words

notThe' :: String -> String
notThe' l@(x0:x1:x2:x3:x4) = case (x0) of
                             ' ' -> case (x4) of
                                      (' ':_) -> case (x1:x2:x3:[]) of
                                                    "the" -> notThe' x4
                                                    "The" -> notThe' x4
                                                    _ -> x0 : (notThe' $ tail l)
                                      [] -> case (x1:x2:x3:[]) of
                                              "the" -> []
                                              "The" -> []
                                              _ -> (x1:x2:x3:[])
                                      _  -> x0 : (notThe' $ tail l)
                             _  -> x0 : (notThe' $ tail l)

notThe' l@(x0:x1:x2:[]) = l
notThe' l@(x0:x1:[]) = l
notThe' l@(x0:[]) = l
notThe' "" = ""

wrapper :: String -> Maybe String
wrapper str = case str of
                  "" -> Nothing
                  x -> Just x

notThe'' :: String -> Maybe String
-- start case
notThe'' l@(x:[]) = Just l
notThe'' l@(x0:x1:[]) = Just l
notThe'' l@(x0:x1:x2:[]) = case l of
                             "The" -> Nothing
                             "the" -> Nothing
                             _ -> Just l
notThe'' l@(x0:x1:x2:x3:[]) = case x3 of
                                ' ' -> case init l of
                                         "The" -> Just $ x3:[]
                                         "the" -> Just $ x3:[]
                                _ -> Just l
-- for middle and end case
notThe'' lst = wrapper . notThe' $ lst