Arrows that are also Functors

[Maciej Marcin Piechotka]

On Tue, 2011-04-19 at 23:48 -0400, Tyson Whitehead wrote:
> On April 19, 2011 23:22:12 Tyson Whitehead wrote:
> > ArrowLoop from MonadFix
> > 
> >   loop' f = fst' .' loop'' (f .' arr' (second snd))
> >     where loop'' f = mfix (\y -> f .' arr' (,y))
> 
> BTW haskellers, I've been wondering if mfix would better be defined as
> 
>   mfix' :: (m a -> m a) -> m a
> 
> where "mfix' f = mfix (f . pure)" for the computational monads.  The advantage 
> being you can give a useful definition for structural monads as well.
> 

What would be the difference with fix?

Regards
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