Remove the hasGenerics field of TyCon, improve the way the Generics flags is handled...

[ghc-hetmet.git] / compiler / types / Generics.lhs

diff --git a/compiler/types/Generics.lhs b/compiler/types/Generics.lhs
index f8d30fd..6aebe4c 100644 (file)
--- a/compiler/types/Generics.lhs
+++ b/compiler/types/Generics.lhs
@@ -26,7 +26,7 @@ import PrelNames
 import TcEnv (tcLookupTyCon)
 import TcRnMonad (TcM, newUnique)
 import HscTypes
-       
+
 import SrcLoc
 import Bag
 import Outputable 
@@ -42,18 +42,24 @@ import FastString
 %************************************************************************
 
 \begin{code}
-canDoGenerics :: ThetaType -> [DataCon] -> Bool
+canDoGenerics :: TyCon -> Bool
 -- Called on source-code data types, to see if we should generate
--- generic functions for them.  (This info is recorded in the interface file for
--- imported data types.)
-
-canDoGenerics stupid_theta data_cs
-  =  not (any bad_con data_cs)         -- See comment below
-  
-  -- && not (null data_cs)     -- No values of the type
-  -- JPM: we now support empty datatypes
-  
-     && null stupid_theta -- We do not support datatypes with context (for now)
+-- generic functions for them.
+
+canDoGenerics tycon
+  =  let result = not (any bad_con (tyConDataCons tycon))      -- See comment below
+                  -- We do not support datatypes with context (for now)
+                  && null (tyConStupidTheta tycon)
+{-
+                  -- Primitives are (probably) not representable either
+                  && not (isPrimTyCon tycon)
+                  -- Foreigns are (probably) not representable either
+                  && not (isForeignTyCon tycon)
+-}
+                  -- We don't like type families
+                  && not (isFamilyTyCon tycon)
+
+     in {- pprTrace "canDoGenerics" (ppr (tycon,result)) -} result
   where
     bad_con dc = any bad_arg_type (dataConOrigArgTys dc) || not (isVanillaDataCon dc)
        -- If any of the constructor has an unboxed type as argument,
@@ -65,8 +71,6 @@ canDoGenerics stupid_theta data_cs
 
        -- Nor if the args are polymorphic types (I don't think)
     bad_arg_type ty = isUnLiftedType ty || not (isTauTy ty)
-  -- JPM: TODO: I'm not sure I know what isTauTy checks for, so I'm leaving it
-       -- like this for now...
 \end{code}
 
 %************************************************************************
@@ -111,6 +115,7 @@ tc_mkRep0Ty tycon metaDts =
     c1 <- tcLookupTyCon c1TyConName
     s1 <- tcLookupTyCon s1TyConName
     rec0 <- tcLookupTyCon rec0TyConName
+    par0 <- tcLookupTyCon par0TyConName
     u1 <- tcLookupTyCon u1TyConName
     v1 <- tcLookupTyCon v1TyConName
     plus <- tcLookupTyCon sumTyConName
@@ -119,6 +124,7 @@ tc_mkRep0Ty tycon metaDts =
     let mkSum' a b = mkTyConApp plus  [a,b]
         mkProd a b = mkTyConApp times [a,b]
         mkRec0 a   = mkTyConApp rec0  [a]
+        mkPar0 a   = mkTyConApp par0  [a]
         mkD    a   = mkTyConApp d1    [metaDTyCon, sumP (tyConDataCons a)]
         mkC  i d a = mkTyConApp c1    [d, prod i (dataConOrigArgTys a)]
         mkS    d a = mkTyConApp s1    [d, a]
@@ -136,7 +142,11 @@ tc_mkRep0Ty tycon metaDts =
                         foldBal mkProd [ arg d a 
                                        | (d,a) <- zip (metaSTyCons !! i) l ]
         
-        arg d t = mkS d (mkRec0 t)
+        arg d t = mkS d (recOrPar t (getTyVar_maybe t))
+        -- Argument is not a type variable, use Rec0
+        recOrPar t Nothing  = mkRec0 t
+        -- Argument is a type variable, use Par0
+        recOrPar t (Just _) = mkPar0 t
         
         metaDTyCon  = mkTyConTy (metaD metaDts)
         metaCTyCons = map mkTyConTy (metaC metaDts)
@@ -318,9 +328,9 @@ genLR_E i n e
 --------------------------------------------------------------------------------
 
 -- Build a product expression
-mkProd_E :: US                   -- Base for unique names
-              -> [RdrName]       -- List of variables matched on the lhs
-              -> LHsExpr RdrName -- Resulting product expression
+mkProd_E :: US             -- Base for unique names
+        -> [RdrName]       -- List of variables matched on the lhs
+        -> LHsExpr RdrName -- Resulting product expression
 mkProd_E _ []   = mkM1_E (nlHsVar u1DataCon_RDR)
 mkProd_E _ vars = mkM1_E (foldBal prod appVars)
                    -- These M1s are meta-information for the constructor
@@ -328,7 +338,6 @@ mkProd_E _ vars = mkM1_E (foldBal prod appVars)
     appVars = map wrapArg_E vars
     prod a b = prodDataCon_RDR `nlHsApps` [a,b]
 
--- TODO: Produce a P0 when v is a parameter
 wrapArg_E :: RdrName -> LHsExpr RdrName
 wrapArg_E v = mkM1_E (k1DataCon_RDR `nlHsVarApps` [v])
               -- This M1 is meta-information for the selector
@@ -344,7 +353,6 @@ mkProd_P _ vars = mkM1_P (foldBal prod appVars)
     appVars = map wrapArg_P vars
     prod a b = prodDataCon_RDR `nlConPat` [a,b]
     
--- TODO: Produce a P0 when v is a parameter
 wrapArg_P :: RdrName -> LPat RdrName
 wrapArg_P v = mkM1_P (k1DataCon_RDR `nlConVarPat` [v])
               -- This M1 is meta-information for the selector