On Tue, Jan 14, 2014 at 04:57:14PM +1000, Tony Morris wrote: > Why not generalise to any functor? > > let flip f a = fmap ($a) f FYI, this is Control.Lens.?? http://hackage.haskell.org/package/lens-3.9.2/docs/src/Control-Lens-Combinators.html#%3F%3F Tom