+buildLengthPA :: TyCon -> VM CoreExpr
+buildLengthPA repr_tc
+ = do
+ arg <- newLocalVar FSLIT("xs") arg_ty
+ shape <- newLocalVar FSLIT("sel") shape_ty
+ body <- lengthPA (Var shape)
+ return . Lam arg
+ $ Case (Var arg) (mkWildId arg_ty) intPrimTy
+ [(DataAlt repr_dc, shape : map mkWildId repr_tys, body)]
+ where
+ arg_ty = mkTyConApp repr_tc . mkTyVarTys $ tyConTyVars repr_tc
+ [repr_dc] = tyConDataCons repr_tc
+ shape_ty : repr_tys = dataConRepArgTys repr_dc
+
+
+-- data T = C0 t1 ... tm
+-- ...
+-- Ck u1 ... un
+--
+-- data [:T:] = A ![:Int:] [:t1:] ... [:un:]
+--
+-- replicatePA :: Int# -> T -> [:T:]
+-- replicatePA n# t
+-- = let c = case t of
+-- C0 _ ... _ -> 0
+-- ...
+-- Ck _ ... _ -> k
+--
+-- xs1 = case t of
+-- C0 x1 _ ... _ -> replicatePA @t1 n# x1
+-- _ -> emptyPA @t1
+--
+-- ...
+--
+-- ysn = case t of
+-- Ck _ ... _ yn -> replicatePA @un n# yn
+-- _ -> emptyPA @un
+-- in
+-- A (replicatePA @Int n# c) xs1 ... ysn
+--
+--
+
+buildReplicatePA :: TyCon -> TyCon -> VM CoreExpr
+buildReplicatePA vect_tc arr_tc
+ = do
+ len_var <- newLocalVar FSLIT("n") intPrimTy
+ val_var <- newLocalVar FSLIT("x") val_ty
+
+ let len = Var len_var
+ val = Var val_var
+
+ shape <- replicatePA len (ctr_num val)
+ reprs <- liftM concat $ mapM (mk_comp_arrs len val) vect_dcs
+
+ return . mkLams [len_var, val_var]
+ $ mkConApp arr_dc (map (Type . TyVarTy) (tyConTyVars arr_tc) ++ (shape : reprs))
+ where
+ val_ty = mkTyConApp vect_tc . mkTyVarTys $ tyConTyVars arr_tc
+ wild = mkWildId val_ty
+ vect_dcs = tyConDataCons vect_tc
+ [arr_dc] = tyConDataCons arr_tc
+
+ ctr_num val = Case val wild intTy (zipWith ctr_num_alt vect_dcs [0..])
+ ctr_num_alt dc i = (DataAlt dc, map mkWildId (dataConRepArgTys dc),
+ mkConApp intDataCon [mkIntLitInt i])
+
+
+ mk_comp_arrs len val dc = let tys = dataConRepArgTys dc
+ wilds = map mkWildId tys
+ in
+ sequence (zipWith3 (mk_comp_arr len val dc)
+ tys (inits wilds) (tails wilds))
+
+ mk_comp_arr len val dc ty pre (_:post)
+ = do
+ var <- newLocalVar FSLIT("x") ty
+ rep <- replicatePA len (Var var)
+ empty <- emptyPA ty
+ arr_ty <- mkPArrayType ty
+
+ return $ Case val wild arr_ty
+ [(DataAlt dc, pre ++ (var : post), rep), (DEFAULT, [], empty)]
+