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[ghc-hetmet.git] / compiler / basicTypes / DataCon.lhs

diff --git a/compiler/basicTypes/DataCon.lhs b/compiler/basicTypes/DataCon.lhs
index 2c4400b..0c6e3c5 100644 (file)
--- a/compiler/basicTypes/DataCon.lhs
+++ b/compiler/basicTypes/DataCon.lhs
@@ -44,7 +44,6 @@ import ListSetOps
 import Util
 import Maybes
 import FastString
 import Util
 import Maybes
 import FastString

-import PackageConfig

 import Module
 
 import Data.Char
 import Module
 
 import Data.Char

@@ -88,15 +87,20 @@ differently, as follows.
 
 Note [Data Constructor Naming]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Note [Data Constructor Naming]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

-Each data constructor C has two, and possibly three, Names associated with it:
+Each data constructor C has two, and possibly up to four, Names associated with it:

 
 

-                            OccName    Name space      Used for
+                            OccName    Name space      Name of

   ---------------------------------------------------------------------------
   ---------------------------------------------------------------------------

-  * The "source data con"      C       DataName        The DataCon itself
-  * The "real data con"                C       VarName         Its worker Id
-  * The "wrapper data con"     $WC     VarName         Wrapper Id (optional)
-
-Each of these three has a distinct Unique.  The "source data con" name
+  * 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
+ 
+EVERY data constructor (incl for newtypes) has the former two (the
+data con itself, and its worker.  But only some data constructors have a
+wrapper (see Note [The need for a wrapper]).
+
+Each of these three has a distinct Unique.  The "data con itself" name

 appears in the output of the renamer, and names the Haskell-source
 data constructor.  The type checker translates it into either the wrapper Id
 (if it exists) or worker Id (otherwise).
 appears in the output of the renamer, and names the Haskell-source
 data constructor.  The type checker translates it into either the wrapper Id
 (if it exists) or worker Id (otherwise).

@@ -130,6 +134,8 @@ The "wrapper Id", $WC, goes as follows
   nothing for the wrapper to do.  That is, if its defn would be
        $wC = C
 
   nothing for the wrapper to do.  That is, if its defn would be
        $wC = C
 

+Note [The need for a wrapper]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 Why might the wrapper have anything to do?  Two reasons:
 
 * Unboxing strict fields (with -funbox-strict-fields)
 Why might the wrapper have anything to do?  Two reasons:
 
 * Unboxing strict fields (with -funbox-strict-fields)

@@ -153,6 +159,8 @@ Why might the wrapper have anything to do?  Two reasons:
   The third argument is a coerion
        [a] :: [a]:=:[a]
 
   The third argument is a coerion
        [a] :: [a]:=:[a]
 

+INVARIANT: the dictionary constructor for a class
+          never has a wrapper.

 
 
 A note about the stupid context
 
 
 A note about the stupid context

@@ -525,6 +533,7 @@ mkDataCon name declared_infix
 eqSpecPreds :: [(TyVar,Type)] -> ThetaType
 eqSpecPreds spec = [ mkEqPred (mkTyVarTy tv, ty) | (tv,ty) <- spec ]
 
 eqSpecPreds :: [(TyVar,Type)] -> ThetaType
 eqSpecPreds spec = [ mkEqPred (mkTyVarTy tv, ty) | (tv,ty) <- spec ]
 

+mk_dict_strict_mark :: PredType -> StrictnessMark

 mk_dict_strict_mark pred | isStrictPred pred = MarkedStrict
                         | otherwise         = NotMarkedStrict
 \end{code}
 mk_dict_strict_mark pred | isStrictPred pred = MarkedStrict
                         | otherwise         = NotMarkedStrict
 \end{code}

@@ -608,6 +617,7 @@ dataConSourceArity dc = length (dcOrigArgTys dc)
 -- {\em representation} of the data constructor.  This may be more than appear
 -- in the source code; the extra ones are the existentially quantified
 -- dictionaries
 -- {\em representation} of the data constructor.  This may be more than appear
 -- in the source code; the extra ones are the existentially quantified
 -- dictionaries

+dataConRepArity :: DataCon -> Int

 dataConRepArity (MkData {dcRepArgTys = arg_tys}) = length arg_tys
 
 isNullarySrcDataCon, isNullaryRepDataCon :: DataCon -> Bool
 dataConRepArity (MkData {dcRepArgTys = arg_tys}) = length arg_tys
 
 isNullarySrcDataCon, isNullaryRepDataCon :: DataCon -> Bool

@@ -784,14 +794,16 @@ splitProductType_maybe ty
           where
              data_con = ASSERT( not (null (tyConDataCons tycon)) ) 
                         head (tyConDataCons tycon)
           where
              data_con = ASSERT( not (null (tyConDataCons tycon)) ) 
                         head (tyConDataCons tycon)

-       other -> Nothing
+       _other -> Nothing

 
 

+splitProductType :: String -> Type -> (TyCon, [Type], DataCon, [Type])

 splitProductType str ty
   = case splitProductType_maybe ty of
        Just stuff -> stuff
        Nothing    -> pprPanic (str ++ ": not a product") (pprType ty)
 
 
 splitProductType str ty
   = case splitProductType_maybe ty of
        Just stuff -> stuff
        Nothing    -> pprPanic (str ++ ": not a product") (pprType ty)
 
 

+deepSplitProductType_maybe :: Type -> Maybe (TyCon, [Type], DataCon, [Type])

 deepSplitProductType_maybe ty
   = do { (res@(tycon, tycon_args, _, _)) <- splitProductType_maybe ty
        ; let {result 
 deepSplitProductType_maybe ty
   = do { (res@(tycon, tycon_args, _, _)) <- splitProductType_maybe ty
        ; let {result 

@@ -804,6 +816,7 @@ deepSplitProductType_maybe ty
        ; result
        }
           
        ; result
        }
           

+deepSplitProductType :: String -> Type -> (TyCon, [Type], DataCon, [Type])

 deepSplitProductType str ty 
   = case deepSplitProductType_maybe ty of
       Just stuff -> stuff
 deepSplitProductType str ty 
   = case deepSplitProductType_maybe ty of
       Just stuff -> stuff