X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FbasicTypes%2FDataCon.lhs;h=e4da52793c407117dce1fb0ed5202f5ecd95aa01;hp=df8af8e221045eadb411b98a3733ff9eb4b92549;hb=f278f0676579f67075033a4f9857715909c4b71e;hpb=7299e42cc5214458ba16034dbfbf58de55f7121b

diff --git a/compiler/basicTypes/DataCon.lhs b/compiler/basicTypes/DataCon.lhs
index df8af8e..e4da527 100644
--- a/compiler/basicTypes/DataCon.lhs
+++ b/compiler/basicTypes/DataCon.lhs
@@ -15,9 +15,11 @@ module DataCon (
 	
 	-- ** Type deconstruction
 	dataConRepType, dataConSig, dataConFullSig,
-	dataConName, dataConIdentity, dataConTag, dataConTyCon, dataConUserType,
+	dataConName, dataConIdentity, dataConTag, dataConTyCon, 
+        dataConOrigTyCon, dataConUserType,
 	dataConUnivTyVars, dataConExTyVars, dataConAllTyVars, 
-	dataConEqSpec, eqSpecPreds, dataConEqTheta, dataConDictTheta, dataConStupidTheta, 
+	dataConEqSpec, eqSpecPreds, dataConEqTheta, dataConDictTheta,
+	dataConStupidTheta,  
 	dataConInstArgTys, dataConOrigArgTys, dataConOrigResTy,
 	dataConInstOrigArgTys, dataConRepArgTys, 
 	dataConFieldLabels, dataConFieldType,
@@ -49,10 +51,10 @@ import Outputable
 import Unique
 import ListSetOps
 import Util
-import Maybes
 import FastString
 import Module
 
+import qualified Data.Data as Data
 import Data.Char
 import Data.Word
 import Data.List ( partition )
@@ -96,12 +98,12 @@ Note [Data Constructor Naming]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Each data constructor C has two, and possibly up to four, Names associated with it:
 
-			     OccName	Name space	Name of
-  ---------------------------------------------------------------------------
-  * The "data con itself" 	C	DataName	DataCon
-  * The "worker data con"	C	VarName		Id (the worker)
-  * The "wrapper data con"	\$WC	VarName		Id (the wrapper)
-  * The "newtype coercion"      :CoT    TcClsName	TyCon
+		   OccName   Name space	  Name of   Notes
+ ---------------------------------------------------------------------------
+ The "data con itself" 	 C     DataName	  DataCon   In dom( GlobalRdrEnv )
+ The "worker data con"	 C     VarName	  Id        The worker
+ The "wrapper data con"	 $WC   VarName	  Id        The wrapper
+ The "newtype coercion"  :CoT  TcClsName  TyCon
  
 EVERY data constructor (incl for newtypes) has the former two (the
 data con itself, and its worker.  But only some data constructors have a
@@ -269,8 +271,9 @@ data DataCon
 		--	 syntax, provided its type looks like the above.
 		--       The declaration format is held in the TyCon (algTcGadtSyntax)
 
-	dcUnivTyVars :: [TyVar],	-- Universally-quantified type vars 
+	dcUnivTyVars :: [TyVar],	-- Universally-quantified type vars [a,b,c]
 					-- INVARIANT: length matches arity of the dcRepTyCon
+					---           result type of (rep) data con is exactly (T a b c)
 
 	dcExTyVars   :: [TyVar],	-- Existentially-quantified type vars 
 		-- In general, the dcUnivTyVars are NOT NECESSARILY THE SAME AS THE TYVARS
@@ -318,7 +321,6 @@ data DataCon
 	dcOrigArgTys :: [Type],		-- Original argument types
 					-- (before unboxing and flattening of strict fields)
 	dcOrigResTy :: Type,		-- Original result type, as seen by the user
-		-- INVARIANT: mentions only dcUnivTyVars
 		-- NB: for a data instance, the original user result type may 
 		-- differ from the DataCon's representation TyCon.  Example
 		--	data instance T [a] where MkT :: a -> T [a]
@@ -453,6 +455,15 @@ instance Outputable DataCon where
 
 instance Show DataCon where
     showsPrec p con = showsPrecSDoc p (ppr con)
+
+instance Data.Typeable DataCon where
+    typeOf _ = Data.mkTyConApp (Data.mkTyCon "DataCon") []
+
+instance Data.Data DataCon where
+    -- don't traverse?
+    toConstr _   = abstractConstr "DataCon"
+    gunfold _ _  = error "gunfold"
+    dataTypeOf _ = mkNoRepType "DataCon"
 \end{code}
 
 
@@ -564,6 +575,14 @@ dataConTag  = dcTag
 dataConTyCon :: DataCon -> TyCon
 dataConTyCon = dcRepTyCon
 
+-- | The original type constructor used in the definition of this data
+-- constructor.  In case of a data family instance, that will be the family
+-- type constructor.
+dataConOrigTyCon :: DataCon -> TyCon
+dataConOrigTyCon dc 
+  | Just (tc, _) <- tyConFamInst_maybe (dcRepTyCon dc) = tc
+  | otherwise                                          = dcRepTyCon dc
+
 -- | The representation type of the data constructor, i.e. the sort
 -- type that will represent values of this type at runtime
 dataConRepType :: DataCon -> Type
@@ -636,8 +655,10 @@ dataConFieldLabels = dcFields
 
 -- | Extract the type for any given labelled field of the 'DataCon'
 dataConFieldType :: DataCon -> FieldLabel -> Type
-dataConFieldType con label = expectJust "unexpected label" $
-    lookup label (dcFields con `zip` dcOrigArgTys con)
+dataConFieldType con label
+  = case lookup label (dcFields con `zip` dcOrigArgTys con) of
+      Just ty -> ty
+      Nothing -> pprPanic "dataConFieldType" (ppr con <+> ppr label)
 
 -- | The strictness markings decided on by the compiler.  Does not include those for
 -- existential dictionaries.  The list is in one-to-one correspondence with the arity of the 'DataCon'
@@ -726,7 +747,7 @@ dataConUserType :: DataCon -> Type
 --
 -- rather than:
 --
--- > T :: forall a c. forall b. (c=[a]) => a -> b -> T c
+-- > T :: forall a c. forall b. (c~[a]) => a -> b -> T c
 --
 -- NB: If the constructor is part of a data instance, the result type
 -- mentions the family tycon, not the internal one.