keyword :: TokenParser String
keyword = token go P.<?> "keyword"
  where go (Keyword s) = Just s
        go _           = Nothing
keyword :: TokenParser String
keyword = token go P.<?> "keyword"
  where go (Keyword s) = Just s
        go _           = Nothing
keyword = token go P.<?> "keyword"
  where go (Keyword s) = Just s
        go _           = Nothing