Kindness of strangers (or strangeness of Kinds)
anthony_clayden at clear.net.nz
Fri Jun 8 01:36:55 CEST 2012
José Pedro Magalhães <jpm <at> cs.uu.nl> writes:
> On Thu, Jun 7, 2012 at 2:46 AM, AntC <anthony_clayden <at> clear.net.nz>
> What does the `ArgKind' message mean?
> `ArgKind` and `OpenKind` is what previously was called `?` and `??` (or the
otherway around; I can't remember).
Thanks Pedro, I'm trying to understand what's changing and why. (And I'd
better repeat that I'm looking at 7.4.1, not HEAD; and SPJ's being perfectly
clear that the promoted Kind stuff is not yet officially approved for prime
GHC 7.2.1> :k (->) :: ?? -> ? -> *
GHC 7.4.1> :k (->) :: * -> * -> *
At first sight (->) is becoming less polyKinded. Is the eventual aim to be:
GHC 7.6+> :k (->) :: AnyKind1 -> AnyKind2 -> *
>You might also want to have a look at Richard and Stephanie's latest paper
draft, about singletons, which is related to what you are trying in your
That's what I'm doing, and trying to understand the machinery behind it. The
naieve approach I started with was how to get one-way from type to its single
value -- I wasn't aiming for the whole singleton gig.
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