Filtering composite structures with Lens

Question

I have a [(a, Maybe b)], and want to obtain a [(a, b)], with all pairs where the second element was Nothing filtered out. Is there a concise way to describe this operation using lens?

Answer 1

Notwithstanding the ingeniousity of the Lenses, the follwoing would probably be the mark for conciseness:

[ (a, b) | (a, Just b) <- list ]

(Not to speak of readability.)