import Control.Monad
import Text.Printf

editor :: String -> String
editor = uncurry ((++) . reverse) . foldl f ("","")
    where
      f (ls,r:rs) ']' = (r:ls,rs)
      f (ls,  "") ']' = (ls,  "")
      f (l:ls,rs) '[' = (ls,l:rs)
      f ("",  rs) '[' = ("",  rs)
      f (ls,  rs)  x  = (x:ls,rs)

main :: IO ()
main = forM_ ["abc[-[[/", "a[b[c]]d", "a[[[[b]]]]]]c"]
       $ liftM2 (printf "\"%s\" -> \"%s\"\n") id editor