Kindness of strangers (or strangeness of Kinds)
AntC
anthony_clayden at clear.net.nz
Tue Jun 12 08:26:46 CEST 2012
Edward Kmett <ekmett <at> gmail.com> writes:
> On Mon, Jun 11, 2012 at 9:58 PM, AntC <anthony_clayden <at> clear.net.nz>
wrote:
>>
>> [snip ...]
>>
>> Could we have :k (->) :: OpenKind -> * -> * -- why not?
>
> I don't quite understand why you would want arbitrary kinded arguments, but
only in negative position.
>
Thanks Edward, oops I've used the wrong terminology, sorry for the confusion.
I didn't mean OpenKind but AnyKind. I put that only in a negative position
more to sharpen the question, but also because I assumed the result from (->)
would have to be grounded in Kind *; and then at least one of its arguments
would also have to be grounded in Kind *.
I think perhaps(?) more PolyKindness is on the horizon:
http://hackage.haskell.org/trac/ghc/wiki/GhcKinds (section on GADKs, and sub-
pages on KindPolymorphism and ExplicitTypeApplication). I guess GHC is getting
there by small steps, and doesn't yet have powerful enough Kind refinement nor
Kind equality constraints, nor interleaving of Type and Kind inference.
More information about the Glasgow-haskell-users
mailing list