tk' :: (TT -> Bool) -> (TT -> Endo [Stroke]) -> TT -> Endo [Stroke]
tk' f s t | isErr t = errStyle t
          | tokT t `elem` fmap Reserved [As, Qualified, Hiding]
            = one $ (fmap (const variableStyle) . tokToSpan) t
          | f t = s t
          | otherwise = one (ts t)
tk' :: (TT -> Bool) -> (TT -> Endo [Stroke]) -> TT -> Endo [Stroke]
tk' f s t | isErr t = errStyle t
          | tokT t `elem` fmap Reserved [As, Qualified, Hiding]
            = one $ (fmap (const variableStyle) . tokToSpan) t
          | f t = s t
          | otherwise = one (ts t)
tk' f s t | isErr t = errStyle t
          | tokT t `elem` fmap Reserved [As, Qualified, Hiding]
            = one $ (fmap (const variableStyle) . tokToSpan) t
          | f t = s t
          | otherwise = one (ts t)