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<p>I did, see here: <a moz-do-not-send="true"
href="https://gitlab.haskell.org/jvanbruegge/ghc/blob/73b383275f3d497338ca50a3a7934445c3858450/compiler/prelude/TysWiredIn.hs#L235">https://gitlab.haskell.org/jvanbruegge/ghc/blob/73b383275f3d497338ca50a3a7934445c3858450/compiler/prelude/TysWiredIn.hs#L235</a><br>
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<div class="moz-cite-prefix">Am 03.04.19 um 16:28 schrieb Simon
Peyton Jones:<br>
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<p class="MsoNormal"><span
style="color:windowtext;mso-fareast-language:EN-US">Make
sure you add the new wired in this to
`TysWiredIn.wiredInTyCons`<o:p></o:p></span></p>
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style="color:windowtext;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="color:windowtext"
lang="EN-US">From:</span></b><span
style="color:windowtext" lang="EN-US"> ghc-devs
<a class="moz-txt-link-rfc2396E" href="mailto:ghc-devs-bounces@haskell.org"><ghc-devs-bounces@haskell.org></a>
<b>On Behalf Of </b>Jan van Brügge<br>
<b>Sent:</b> 03 April 2019 12:06<br>
<b>To:</b> <a class="moz-txt-link-abbreviated" href="mailto:ghc-devs@haskell.org">ghc-devs@haskell.org</a><br>
<b>Subject:</b> Defining a wired-in type of a
different kind<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<pre>Hi,<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>when trying to get familiar with the GHC code base for my Bachelor's<o:p></o:p></pre>
<pre>thesis. I followed the GHC Wiki, especially the case study about the<o:p></o:p></pre>
<pre>bool type.<o:p></o:p></pre>
<pre>Now I wanted to add a new kind and a new type inhabiting this kind<o:p></o:p></pre>
<pre>(without having to expose a data constructor, so without datatype<o:p></o:p></pre>
<pre>promotion).<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>So in TysWiredIn.hs I added the new TyCons and added them to the list of<o:p></o:p></pre>
<pre>wired-in types:<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>-- data Row a b<o:p></o:p></pre>
<pre>rowKindCon :: TyCon<o:p></o:p></pre>
<pre>rowKindCon = pcTyCon rowKindConName Nothing [alphaTyVar, betaTyVar] []<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>rowKind :: Kind<o:p></o:p></pre>
<pre>rowKind = mkTyConTy rowKindCon<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>-- data RNil :: Row a b<o:p></o:p></pre>
<pre>rnilTyCon :: TyCon<o:p></o:p></pre>
<pre>rnilTyCon = mkAlgTyCon rnilTyConName [] rowKind [] Nothing []<o:p></o:p></pre>
<pre> (mkDataTyConRhs [])<o:p></o:p></pre>
<pre> (VanillaAlgTyCon (mkPrelTyConRepName rnilTyConName))<o:p></o:p></pre>
<pre> False<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>rnilTy :: Type<o:p></o:p></pre>
<pre>rnilTy = mkTyConTy rnilTyCon<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre><o:p> </o:p></pre>
<pre>I also added two new empty data decls to ghc-prim, but if I inspect the<o:p></o:p></pre>
<pre>kind of RNil it is not Row, but Type. So I think I am either<o:p></o:p></pre>
<pre>understanding res_kind wrong or I have to do something completely different.<o:p></o:p></pre>
<pre>I am also not sure how to verify that the code in TysWiredIn.hs is<o:p></o:p></pre>
<pre>working at all, from all what I can tell it could just be the<o:p></o:p></pre>
<pre>declarations in ghc-prim that result in what I see in ghci.<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>Thank you and sorry for my beginner question<o:p></o:p></pre>
<pre>Jan<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
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