gistfile1.hs

ecmascript :: Parser String
ecmascript = lexeme $ char '{' *> ecmascript' 0
  where ecmascript' n = do
          c <- anyChar
          case c of
            '{' -> ('{' :) <$> ecmascript' (succ n)
            '}' -> if n == 0
                   then return ""
                   else ('}' :) <$> ecmascript' (pred n)
            _ -> (c :) <$> ecmascript' n