+ to_repr shape_vars@(len_var : _)
+ repr_vars
+ (SumRepr { sum_components = prods
+ , sum_arr_tycon = tycon
+ , sum_arr_data_con = data_con })
+ = do
+ exprs <- zipWithM (to_prod len_var) repr_vars prods
+
+ return . wrapFamInstBody tycon tys
+ . mkConApp data_con
+ $ map Type tys ++ map Var shape_vars ++ exprs
+ where
+ tys = map reprType prods
+
+ to_repr [len_var] [repr_vars] prod = to_prod len_var repr_vars prod
+
+ to_prod len_var
+ repr_vars
+ (ProdRepr { prod_components = tys
+ , prod_arr_tycon = tycon
+ , prod_arr_data_con = data_con })
+ = return . wrapFamInstBody tycon tys
+ . mkConApp data_con
+ $ map Type tys ++ map Var (len_var : repr_vars)
+
+buildFromArrPRepr :: Repr -> TyCon -> TyCon -> TyCon -> VM CoreExpr
+buildFromArrPRepr repr vect_tc prepr_tc arr_tc
+ = do
+ arg_ty <- mkPArrayType =<< mkPReprType el_ty
+ arg <- newLocalVar FSLIT("xs") arg_ty
+
+ res_ty <- mkPArrayType el_ty
+
+ shape_vars <- arrShapeVars repr
+ repr_vars <- arrReprVars repr
+
+ parray_co <- mkBuiltinCo parrayTyCon
+
+ let Just repr_co = tyConFamilyCoercion_maybe prepr_tc
+ co = mkAppCoercion parray_co
+ $ mkTyConApp repr_co var_tys
+
+ scrut = mkCoerce co (Var arg)
+
+ result = wrapFamInstBody arr_tc var_tys
+ . mkConApp arr_dc
+ $ map Type var_tys ++ map Var (shape_vars ++ concat repr_vars)
+
+ liftM (Lam arg)
+ (from_repr repr scrut shape_vars repr_vars res_ty result)