On Tue, Jan 14, 2014 at 3:30 PM, Christian Marie <christian@ponies.io> wrote:
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

I didn't think of that, I suppose.

Now that I do, it seems to be a tradeoff between (arguably) less immediately
obvious type signatures and something.

I can't actually think of what that something is yet. Can you think of a real
world use for a functor flip where normal flip wouldn't do?

I know I've written "fmap ($a) f" in the past, so I guess any of those would be a use case for a functor flip.  On the other hand, it's only a few characters longer than flip, and arguably more clear, so I'm not convinced that generalizing flip is useful.  YMMV.