+
+
+%************************************************************************
+%* *
+ Reification
+%* *
+%************************************************************************
+
+
+\begin{code}
+reify :: TH.Name -> TcM TH.Info
+reify th_name
+ = do { name <- lookupThName th_name
+ ; thing <- tcLookup name
+ -- ToDo: this tcLookup could fail, which would give a
+ -- rather unhelpful error message
+ ; reifyThing thing
+ }
+
+lookupThName :: TH.Name -> TcM Name
+lookupThName (TH.Name occ (TH.NameG th_ns mod))
+ = lookupOrig (mkModuleName (TH.modString mod))
+ (OccName.mkOccName ghc_ns (TH.occString occ))
+ where
+ ghc_ns = case th_ns of
+ TH.DataName -> dataName
+ TH.TcClsName -> tcClsName
+ TH.VarName -> varName
+
+lookupThName th_name@(TH.Name occ TH.NameS)
+ = do { let rdr_name = mkRdrUnqual (OccName.mkOccFS ns occ_fs)
+ ; rdr_env <- getLocalRdrEnv
+ ; case lookupLocalRdrEnv rdr_env rdr_name of
+ Just name -> return name
+ Nothing -> do
+ { mb_name <- lookupSrcOcc_maybe rdr_name
+ ; case mb_name of
+ Just name -> return name ;
+ Nothing -> failWithTc (notInScope th_name)
+ }}
+ where
+ ns | isLexCon occ_fs = OccName.dataName
+ | otherwise = OccName.varName
+ occ_fs = mkFastString (TH.occString occ)
+
+lookupThName (TH.Name occ (TH.NameU uniq))
+ = return (mkInternalName (mk_uniq uniq) (OccName.mkOccFS bogus_ns occ_fs) noSrcLoc)
+ where
+ occ_fs = mkFastString (TH.occString occ)
+ bogus_ns = OccName.varName -- Not yet recorded in the TH name
+ -- but only the unique matters
+
+mk_uniq :: Int# -> Unique
+mk_uniq u = mkUniqueGrimily (I# u)
+
+notInScope :: TH.Name -> SDoc
+notInScope th_name = quotes (text (show (TH.pprName th_name))) <+>
+ ptext SLIT("is not in scope at a reify")
+ -- Ugh! Rather an indirect way to display the name
+
+------------------------------
+reifyThing :: TcTyThing -> TcM TH.Info
+-- The only reason this is monadic is for error reporting,
+-- which in turn is mainly for the case when TH can't express
+-- some random GHC extension
+
+reifyThing (AGlobal (AnId id))
+ = do { ty <- reifyType (idType id)
+ ; fix <- reifyFixity (idName id)
+ ; let v = reifyName id
+ ; case globalIdDetails id of
+ ClassOpId cls -> return (TH.ClassOpI v ty (reifyName cls) fix)
+ other -> return (TH.VarI v ty Nothing fix)
+ }
+
+reifyThing (AGlobal (ATyCon tc)) = do { dec <- reifyTyCon tc; return (TH.TyConI dec) }
+reifyThing (AGlobal (AClass cls)) = do { dec <- reifyClass cls; return (TH.ClassI dec) }
+reifyThing (AGlobal (ADataCon dc))
+ = do { let name = dataConName dc
+ ; ty <- reifyType (idType (dataConWrapId dc))
+ ; fix <- reifyFixity name
+ ; return (TH.DataConI (reifyName name) ty (reifyName (dataConTyCon dc)) fix) }
+
+reifyThing (ATcId id _ _)
+ = do { ty1 <- zonkTcType (idType id) -- Make use of all the info we have, even
+ -- though it may be incomplete
+ ; ty2 <- reifyType ty1
+ ; fix <- reifyFixity (idName id)
+ ; return (TH.VarI (reifyName id) ty2 Nothing fix) }
+
+reifyThing (ATyVar tv)
+ = do { ty1 <- zonkTcTyVar tv
+ ; ty2 <- reifyType ty1
+ ; return (TH.TyVarI (reifyName tv) ty2) }
+
+------------------------------
+reifyTyCon :: TyCon -> TcM TH.Dec
+reifyTyCon tc
+ | isSynTyCon tc
+ = do { let (tvs, rhs) = getSynTyConDefn tc
+ ; rhs' <- reifyType rhs
+ ; return (TH.TySynD (reifyName tc) (reifyTyVars tvs) rhs') }
+
+ | isNewTyCon tc
+ = do { cxt <- reifyCxt (tyConTheta tc)
+ ; con <- reifyDataCon (head (tyConDataCons tc))
+ ; return (TH.NewtypeD cxt (reifyName tc) (reifyTyVars (tyConTyVars tc))
+ con [{- Don't know about deriving -}]) }
+
+ | otherwise -- Algebraic
+ = do { cxt <- reifyCxt (tyConTheta tc)
+ ; cons <- mapM reifyDataCon (tyConDataCons tc)
+ ; return (TH.DataD cxt (reifyName tc) (reifyTyVars (tyConTyVars tc))
+ cons [{- Don't know about deriving -}]) }
+
+reifyDataCon :: DataCon -> TcM TH.Con
+reifyDataCon dc
+ = do { arg_tys <- reifyTypes (dataConOrigArgTys dc)
+ ; let stricts = map reifyStrict (dataConStrictMarks dc)
+ fields = dataConFieldLabels dc
+ ; if null fields then
+ return (TH.NormalC (reifyName dc) (stricts `zip` arg_tys))
+ else
+ return (TH.RecC (reifyName dc) (zip3 (map reifyName fields) stricts arg_tys)) }
+ -- NB: we don't remember whether the constructor was declared in an infix way
+
+------------------------------
+reifyClass :: Class -> TcM TH.Dec
+reifyClass cls
+ = do { cxt <- reifyCxt theta
+ ; ops <- mapM reify_op op_stuff
+ ; return (TH.ClassD cxt (reifyName cls) (reifyTyVars tvs) ops) }
+ where
+ (tvs, theta, _, op_stuff) = classBigSig cls
+ reify_op (op, _) = do { ty <- reifyType (idType op)
+ ; return (TH.SigD (reifyName op) ty) }
+
+------------------------------
+reifyType :: TypeRep.Type -> TcM TH.Type
+reifyType (TyVarTy tv) = return (TH.VarT (reifyName tv))
+reifyType (TyConApp tc tys) = reify_tc_app (reifyName tc) tys
+reifyType (NewTcApp tc tys) = reify_tc_app (reifyName tc) tys
+reifyType (NoteTy _ ty) = reifyType ty
+reifyType (AppTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (r1 `TH.AppT` r2) }
+reifyType (FunTy t1 t2) = do { [r1,r2] <- reifyTypes [t1,t2] ; return (TH.ArrowT `TH.AppT` r1 `TH.AppT` r2) }
+reifyType ty@(ForAllTy _ _) = do { cxt' <- reifyCxt cxt;
+ ; tau' <- reifyType tau
+ ; return (TH.ForallT (reifyTyVars tvs) cxt' tau') }
+ where
+ (tvs, cxt, tau) = tcSplitSigmaTy ty
+reifyTypes = mapM reifyType
+reifyCxt = mapM reifyPred
+
+reifyTyVars :: [TyVar] -> [TH.Name]
+reifyTyVars = map reifyName
+
+reify_tc_app :: TH.Name -> [TypeRep.Type] -> TcM TH.Type
+reify_tc_app tc tys = do { tys' <- reifyTypes tys
+ ; return (foldl TH.AppT (TH.ConT tc) tys') }
+
+reifyPred :: TypeRep.PredType -> TcM TH.Type
+reifyPred (ClassP cls tys) = reify_tc_app (reifyName cls) tys
+reifyPred p@(IParam _ _) = noTH SLIT("implicit parameters") (ppr p)
+
+
+------------------------------
+reifyName :: NamedThing n => n -> TH.Name
+reifyName thing
+ | isExternalName name = mk_varg mod occ_str
+ | otherwise = TH.mkNameU occ_str (getKey (getUnique name))
+ where
+ name = getName thing
+ mod = moduleUserString (nameModule name)
+ occ_str = occNameUserString occ
+ occ = nameOccName name
+ mk_varg | OccName.isDataOcc occ = TH.mkNameG_d
+ | OccName.isVarOcc occ = TH.mkNameG_v
+ | OccName.isTcOcc occ = TH.mkNameG_tc
+ | otherwise = pprPanic "reifyName" (ppr name)
+
+------------------------------
+reifyFixity :: Name -> TcM TH.Fixity
+reifyFixity name
+ = do { fix <- lookupFixityRn name
+ ; return (conv_fix fix) }
+ where
+ conv_fix (BasicTypes.Fixity i d) = TH.Fixity i (conv_dir d)
+ conv_dir BasicTypes.InfixR = TH.InfixR
+ conv_dir BasicTypes.InfixL = TH.InfixL
+ conv_dir BasicTypes.InfixN = TH.InfixN
+
+reifyStrict :: BasicTypes.StrictnessMark -> TH.Strict
+reifyStrict MarkedStrict = TH.IsStrict
+reifyStrict MarkedUnboxed = TH.IsStrict
+reifyStrict NotMarkedStrict = TH.NotStrict
+
+------------------------------
+noTH :: LitString -> SDoc -> TcM a
+noTH s d = failWithTc (hsep [ptext SLIT("Can't represent") <+> ptext s <+>
+ ptext SLIT("in Template Haskell:"),
+ nest 2 d])
+\end{code}