+ mk_alts _ _ [] = [(DEFAULT, [], Var unitDataConId)]
+ mk_alts [dc] [vars] [expr] = [(DataAlt dc, vars, expr)]
+ mk_alts dcs vars exprs = zipWith4 mk_alt dcs vars sum_data_cons exprs
+
+ mk_alt dc vars sum_dc expr = (DataAlt dc, vars,
+ mkConApp sum_dc (map Type prod_tys ++ [expr]))
+
+ mk_prod _ _ [] = Var unitDataConId
+ mk_prod _ _ [expr] = expr
+ mk_prod (Just dc) tys exprs = mkConApp dc (map Type tys ++ exprs)
+
+buildFromPRepr :: TyConRepr -> TyCon -> TyCon -> TyCon -> VM CoreExpr
+buildFromPRepr (TyConRepr {
+ repr_tys = repr_tys
+ , repr_prod_data_cons = prod_data_cons
+ , repr_prod_tys = prod_tys
+ , repr_sum_data_cons = sum_data_cons
+ , repr_type = repr_type
+ })
+ vect_tc prepr_tc _
+ = do
+ arg_ty <- mkPReprType res_ty
+ arg <- newLocalVar FSLIT("x") arg_ty
+
+ liftM (Lam arg
+ . un_sum (unwrapFamInstScrut prepr_tc var_tys (Var arg)))
+ (sequence
+ $ zipWith4 un_prod data_cons prod_data_cons prod_tys repr_tys)
+ where
+ var_tys = mkTyVarTys $ tyConTyVars vect_tc
+ ty_args = map Type var_tys
+ res_ty = mkTyConApp vect_tc var_tys
+ data_cons = tyConDataCons vect_tc
+
+ un_prod dc _ _ []
+ = do
+ var <- newLocalVar FSLIT("u") unitTy
+ return (var, mkConApp dc ty_args)
+ un_prod dc _ _ [ty]
+ = do
+ var <- newLocalVar FSLIT("x") ty
+ return (var, mkConApp dc (ty_args ++ [Var var]))
+
+ un_prod dc (Just prod_dc) prod_ty tys
+ = do
+ vars <- mapM (newLocalVar FSLIT("x")) tys
+ pv <- newLocalVar FSLIT("p") prod_ty
+
+ let res = mkConApp dc (ty_args ++ map Var vars)
+ expr = Case (Var pv) (mkWildId prod_ty) res_ty
+ [(DataAlt prod_dc, vars, res)]
+
+ return (pv, expr)
+
+ un_sum scrut [(var, expr)] = Let (NonRec var scrut) expr
+ un_sum scrut alts
+ = Case scrut (mkWildId repr_type) res_ty
+ $ zipWith mk_alt sum_data_cons alts