import TcEnv (tcLookupTyCon)
import TcRnMonad (TcM, newUnique)
import HscTypes
-
+
import SrcLoc
import Bag
import Outputable
%************************************************************************
\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,
-- 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}
%************************************************************************
foldBal mkProd [ arg d a
| (d,a) <- zip (metaSTyCons !! i) l ]
- arg d t = trace (showPpr t) $ mkS d (recOrPar t (getTyVar_maybe t))
+ arg d t = mkS d (recOrPar t (getTyVar_maybe t))
-- Argument is not a type variable, use Rec0
- recOrPar t Nothing = trace "Rec0" $ mkRec0 t
+ recOrPar t Nothing = mkRec0 t
-- Argument is a type variable, use Par0
- recOrPar t (Just _) = trace "Par0" $ mkPar0 t
+ recOrPar t (Just _) = mkPar0 t
metaDTyCon = mkTyConTy (metaD metaDts)
metaCTyCons = map mkTyConTy (metaC metaDts)
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
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