Re: Proposal: Add ‘type f ~> g = forall a. f a -> g a’

wren romano winterkoninkje at
Tue Nov 15 05:28:39 UTC 2016

I agree too. I use the name (~>) whenever I have some profunctor-like
type variable. Putting it in a library would be like defining "x" or
"a" in a library. Certainly natural transformations are helpful to
have a library around, but they should be given a better name.

On Mon, Nov 14, 2016 at 1:48 PM, John Wiegley <johnw at> wrote:
>>>>>> "EM" == Eric Mertens <emertens at> writes:
> EM> I'd prefer that we didn't prescribe a meaning to this generally useful
> EM> type operator. This type synonym is very easy to define in any module
> EM> where it's appropriate.
> I agree. Taking "~>" for natural transformations seems too specific.
> --
> John Wiegley                  GPG fingerprint = 4710 CF98 AF9B 327B B80F
>                          60E1 46C4 BD1A 7AC1 4BA2
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