Re: Defining a wired-in type of a different kind

Yeah, sorry, it is here: https://gitlab.haskell.org/jvanbruegge/ghc/commit/73b383275f3d497338ca50a3a7... Am 03.04.19 um 13:11 schrieb Ben Gamari:

On April 3, 2019 7:06:11 AM EDT, "Jan van Brügge" wrote:

...

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 Can you post a full branch? Nothing in particular looks wrong with what you posted here but the PrelNames code is also relevant.

Cheers,

- Ben