Add flipped fmap

Felipe Lessa felipe.lessa at
Thu Apr 8 13:04:45 EDT 2010

On Thu, Apr 8, 2010 at 9:45 AM, Bas van Dijk <v.dijk.bas at> wrote:
> I must say that Brent Yorheys comment about (<**>) not being flip
> (<*>) has made the 'symmetry' argument less convincing and has moved
> me a bit closer to the - camp. However, I'm still for adding it
> because it can make code nicer.

They -- <**> and <$$> -- are symmetric in spirit.  In the case of <$>
and <$$>, the order in which things are evaluated doesn't matter.  So
we may say that <*>, <$>, <**> and <$$> are "always read from left to
right" if we want to.  Well, at least that's how I think ;).

I too would like to see more people reporting their thoughts on this issue.



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