module Exercise04 where

{-WETT-}
xmlLight :: String -> Bool
xmlLight xs = checkTags [] $ map (wordsMapHelper . lineMapHelper '>') $ lineMapHelper '<' $ "test>" ++ xs ++ "</test>"

wordsMapHelper :: [String] -> String
wordsMapHelper xss = if length xss == 2 && length word == 1 then head word else "/"
    where word = words $ head xss

lineMapHelper :: Char -> String -> [String]
lineMapHelper c xs = lines $ map (\x -> if x == c then '\n' else x) $ xs ++ "end"

checkTags :: [String] -> [String] -> Bool
checkTags ass [] = null ass
checkTags ass (zs:zss) = '/' `notElem` zs && checkTags (zs:ass) zss || not (null ass) && tail zs == head ass && checkTags (tail ass) zss

{-TTEW-}