I would suggest that it's easier to define a normal type constructor
and data cons and then promote them.
This is how the runtime rep polymorphism stuff works for instance so
you can look there for inspiration (it's where I look to work out how
to implement multiplicity polymorphism).
Matt
On Wed, Apr 3, 2019 at 12:06 PM Jan van Brügge
Hi,
when trying to get familiar with the GHC code base for my Bachelor's thesis. I followed the GHC Wiki, especially the case study about the bool type. Now I wanted to add a new kind and a new type inhabiting this kind (without having to expose a data constructor, so without datatype promotion).
So in TysWiredIn.hs I added the new TyCons and added them to the list of wired-in types:
-- data Row a b rowKindCon :: TyCon rowKindCon = pcTyCon rowKindConName Nothing [alphaTyVar, betaTyVar] []
rowKind :: Kind rowKind = mkTyConTy rowKindCon
-- data RNil :: Row a b rnilTyCon :: TyCon rnilTyCon = mkAlgTyCon rnilTyConName [] rowKind [] Nothing [] (mkDataTyConRhs []) (VanillaAlgTyCon (mkPrelTyConRepName rnilTyConName)) False
rnilTy :: Type rnilTy = mkTyConTy rnilTyCon
I also added two new empty data decls to ghc-prim, but if I inspect the kind of RNil it is not Row, but Type. So I think I am either understanding res_kind wrong or I have to do something completely different. I am also not sure how to verify that the code in TysWiredIn.hs is working at all, from all what I can tell it could just be the declarations in ghc-prim that result in what I see in ghci.
Thank you and sorry for my beginner question Jan
_______________________________________________ ghc-devs mailing list ghc-devs@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs