ProtoLens.hs

-- pseudo-code, let's consider these types have corresponding lensens
-- from package proto-lens https://github.com/google/proto-lens
data Foo = Foo{foo: Maybe Bar}
data Bar = Bar{bar: Maybe Buz}
data Buz = Buz{buz: Buf}
data Buf = Buf

-- I'm using bind here to handle Maybe
-- Is there better/shorter way to do it
-- with some lens-specific functions?
accessBuf :: Foo -> Maybe Buf
accessBuf x = 
  (x ^. maybe'foo)
    >>= (^. maybe'bar)
    >>= (Just . (^. buz))