Top-down dual of transformOf?

[ozkutuk]

transformOf operates in a bottom-up manner, as explained in the Haddocks:

Transform every element by recursively applying a given Setter in a bottom-up manner.

However, I was unable to find a top-down counterpart in the library, which I found quite surprising. Am I missing something simple here? I think that something like the following is a pretty natural dual of transformOf:

-- | Transform every element by recursively applying a given 'Setter' in a
-- top-down manner.
topDownOf :: ASetter a b a b -> (a -> a) -> a -> b
topDownOf o f = go
  where
    go = over o go . f