{-# LANGUAGE BlockArguments #-}
module Exercise04 where

import Text.ParserCombinators.ReadP

{-WETT-}
xml =
  munch (`notElem` "<>") `sepBy1`
    do string "<"
       t <- munch1 (`notElem` "/<>\t\n\v\f\r \160")
       skipSpaces
       string ">"
       xml
       string "</"
       string t
       skipSpaces
       string ">"

xmlLight :: String -> Bool
xmlLight = null . snd . last . readP_to_S xml
{-TTEW-}