X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FhsSyn%2FHsDecls.lhs;h=09d8d0a560ae92433061552d2bab9b7072d2e2f1;hb=91f37e6a9be2c17642f5beb0a4bdddef2cb6fb37;hp=049f5972091ec48d75cfd7ace4956d7b39b90390;hpb=ab22f4e6456820c1b5169d75f5975a94e61f54ce;p=ghc-hetmet.git

diff --git a/compiler/hsSyn/HsDecls.lhs b/compiler/hsSyn/HsDecls.lhs
index 049f597..09d8d0a 100644
--- a/compiler/hsSyn/HsDecls.lhs
+++ b/compiler/hsSyn/HsDecls.lhs
@@ -344,11 +344,6 @@ Interface file code:
 
 
 \begin{code}
--- TyClDecls are precisely the kind of declarations that can 
--- appear in interface files; or (internally) in GHC's interface
--- for a module.  That's why (despite the misnomer) IfaceSig and ForeignType
--- are both in TyClDecl
-
 -- Representation of indexed types
 -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 -- Kind signatures of indexed types come in two flavours:
@@ -386,12 +381,21 @@ data TyClDecl name
   | TyData {	tcdND     :: NewOrData,
 		tcdCtxt   :: LHsContext name,	 	-- Context
 		tcdLName  :: Located name,	 	-- Type constructor
+
 		tcdTyVars :: [LHsTyVarBndr name], 	-- Type variables
+			
 		tcdTyPats :: Maybe [LHsType name],	-- Type patterns
-		tcdKindSig:: Maybe Kind,		-- Optional kind sig; 
-							-- (only for the 
-							-- 'where' form and
-							-- indexed type sigs)
+			-- Just [t1..tn] for data instance T t1..tn = ...
+			--	in this case tcdTyVars = fv( tcdTyPats )
+			-- Nothing for everything else
+
+		tcdKindSig:: Maybe Kind,		-- Optional kind sig 
+			-- (Just k) for a
+			--	(a) GADT-style 'data', or 'data instance' decl 
+			--		with explicit kind sig
+			--	(b) 'data family' decl, whether or not 
+			--		there is an explicit kind sig
+			--		(this is how we distinguish a data family decl)
 
 		tcdCons	  :: [LConDecl name],	 	-- Data constructors
 			-- For data T a = T1 | T2 a          the LConDecls all have ResTyH98
@@ -405,6 +409,12 @@ data TyClDecl name
 			-- Typically the foralls and ty args are empty, but they
 			-- are non-empty for the newtype-deriving case
     }
+	-- data family:   tcdPats = Nothing, tcdCons = [], tcdKindSig = Just k
+	--
+	-- data instance: tcdPats = Just tys
+	--
+	-- data:	  tcdPats = Nothing, 
+	--		  tcdCons is non-empty *or* tcdKindSig = Nothing
 
   | TyFunction {tcdLName  :: Located name,	        -- type constructor
 		tcdTyVars :: [LHsTyVarBndr name],	-- type variables
@@ -415,8 +425,9 @@ data TyClDecl name
   | TySynonym {	tcdLName  :: Located name,	        -- type constructor
 		tcdTyVars :: [LHsTyVarBndr name],	-- type variables
 		tcdTyPats :: Maybe [LHsType name],	-- Type patterns
-							-- 'Nothing' => vanilla
-							--   type synonym
+			-- See comments for tcdTyPats in TyData
+			-- 'Nothing' => vanilla type synonym
+
 		tcdSynRhs :: LHsType name	        -- synonym expansion
     }
 
@@ -745,12 +756,11 @@ instDeclATs (InstDecl _ _ _ ats) = ats
 \begin{code}
 type LDerivDecl name = Located (DerivDecl name)
 
-data DerivDecl name
-  = DerivDecl (LHsType name) (Located name)
+data DerivDecl name = DerivDecl (LHsType name)
 
 instance (OutputableBndr name) => Outputable (DerivDecl name) where
-    ppr (DerivDecl ty n) 
-        = hsep [ptext SLIT("deriving"), ppr ty, ptext SLIT("for"), ppr n]
+    ppr (DerivDecl ty) 
+        = hsep [ptext SLIT("derived instance"), ppr ty]
 \end{code}
 
 %************************************************************************