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authorƁukasz Hanuszczak <lukasz.hanuszczak@gmail.com>2015-07-29 15:13:26 +0200
committerMateusz Kowalczyk <fuuzetsu@fuuzetsu.co.uk>2015-08-21 18:22:32 +0100
commitde395700afa73065a2ec69ba5e3cc3ec1a474d11 (patch)
treea45e3f8ff7ba1ca28b491d3e32fe20a36784b1bb /haddock-api/src
parent3fb4ec56a9e7fc167c8fd970bc15b554ab85a1c9 (diff)
Introduce alternative type for family declarations.
Diffstat (limited to 'haddock-api/src')
-rw-r--r--haddock-api/src/Haddock/Types.hs31
1 files changed, 31 insertions, 0 deletions
diff --git a/haddock-api/src/Haddock/Types.hs b/haddock-api/src/Haddock/Types.hs
index ac073036..90672c9d 100644
--- a/haddock-api/src/Haddock/Types.hs
+++ b/haddock-api/src/Haddock/Types.hs
@@ -341,6 +341,37 @@ instance OutputableBndr a => Outputable (InstType a) where
ppr (TypeInst a) = text "TypeInst" <+> ppr a
ppr (DataInst a) = text "DataInst" <+> ppr a
+
+-- | Almost the same as 'FamilyDecl' except for type binders.
+--
+-- In order to perform type specialization for class instances, we need to
+-- substitute class variables to appropriate type. However, type variables in
+-- associated type are specified using 'LHsTyVarBndrs' instead of 'HsType'.
+-- This makes type substitution impossible and to overcome this issue,
+-- 'PseudoFamilyDecl' type is introduced.
+data PseudoFamilyDecl name = PseudoFamilyDecl
+ { pfdInfo :: FamilyInfo name
+ , pfdLName :: Located name
+ , pfdTyVars :: [LHsType name]
+ , pfdKindSig :: Maybe (LHsKind name)
+ }
+
+
+mkPseudoFamilyDecl :: FamilyDecl name -> PseudoFamilyDecl name
+mkPseudoFamilyDecl (FamilyDecl { .. }) = PseudoFamilyDecl
+ { pfdInfo = fdInfo
+ , pfdLName = fdLName
+ , pfdTyVars = [ L loc (mkType bndr) | L loc bndr <- hsq_tvs fdTyVars ]
+ , pfdKindSig = fdKindSig
+ }
+ where
+ mkType (KindedTyVar (L loc name) lkind) =
+ HsKindSig tvar lkind
+ where
+ tvar = L loc (HsTyVar name)
+ mkType (UserTyVar name) = HsTyVar name
+
+
-- | An instance head that may have documentation and a source location.
type DocInstance name = (InstHead name, Maybe (MDoc name), Located name)