For more immediate satisfaction (i.e., before we get around to updating GHC in the manner suggested on the wiki page), you have to use a parameterized type and then specialize it to *:

> data Prom2 a = Typic a

Now, we have (Prom2 * :: BOX) with (Typic Int :: Prom2 *).

Unfortunately, we have no kind synonyms, so you have to insert the * parameter every time you want to use the Prom2 kind. As Pedro suggests, this is a known weakness of the current system.

Richard

On Apr 2, 2013, at 8:55 AM, José Pedro Magalhães <jpm@cs.uu.nl> wrote:

Hi Gabor,

See http://hackage.haskell.org/trac/ghc/wiki/GhcKinds/KindsWithoutData
Comments on that discussion are welcome.


Cheers,
Pedro

On Tue, Apr 2, 2013 at 2:51 PM, Gabor Greif <ggreif@gmail.com> wrote:

Hi devs!

I guess I found a gap in the promotion mechanism:

> data Prom1 = Symic Symbol

gets promoted to to a kind (Prom1 :: BOX) with (Symic "AAA" :: Prom1).
So far so good.

But how can I define by promotion (Prom2 :: BOX) with (Typic Int :: Prom2) ?

I'd like to write

> data Prom2 = Typic Type

but haven't found such a beast in TypeLits. So my question is
basically, which type-level identifier promotes to (* :: BOX) when
mentioned in a `data` definition?

I am thankful for any hints!

Cheers,

    Gabor

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