Hi guys, I'll have a go at implementing 'data kind'. I've been a bit busy lately but things are getting back to normal, and a colleague of mine is willing to help too, so hopefully we can get it done.
-Iavor On Wed, Apr 3, 2013 at 4:24 AM, Simon Peyton-Jones <simo...@microsoft.com>wrote: > For the record, I’m good with going ahead with “Solution 2” on **** > > ** ** > > http://hackage.haskell.org/trac/ghc/wiki/GhcKinds/KindsWithoutData**** > > ** ** > > if anyone wants to execute on it.**** > > > Simon**** > > ** ** > > *From:* ghc-devs-boun...@haskell.org [mailto:ghc-devs-boun...@haskell.org] > *On Behalf Of *Iavor Diatchki > *Sent:* 02 April 2013 17:49 > *To:* Richard Eisenberg > *Cc:* José Pedro Magalhães; ghc-devs > *Subject:* Re: What promotes to (* :: BOX) ?**** > > ** ** > > Hello,**** > > ** ** > > I've been using an existential quantifier for this. It**** > > looks weird (and I think we should fix this as discussed) but it is the > current workaround:**** > > ** ** > > data MyKind = forall star. T star**** > > ** ** > > -- T :: * -> MyKind**** > > ** ** > > -Iavor**** > > ** ** > > ** ** > > ** ** > > On Tue, Apr 2, 2013 at 7:11 AM, Richard Eisenberg <e...@cis.upenn.edu> > wrote:**** > > 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 <j...@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 <ggr...@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 > > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs**** > > > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs**** > > ** ** > > > _______________________________________________ > ghc-devs mailing list > ghc-devs@haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs**** > > ** ** >
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