Creative uses of arrows

Question

I just read the post Creative uses of monads, that is crowded of very interesting ideas and references, so I got curious: what about arrows? I\'m not looking for personal opinio

Answer 1

One of the first Haskell modules I ever wrote was a sort of quantum-imperative arrow with "wavefunction collapse" whenever I/O was done. http://hackage.haskell.org/package/quantum-arrow