[walker] no need to wrap appended walkers specially

dune/xt/grid/walker.hh

@@ -302,59 +302,6 @@ public:
                         ApplyOn::LambdaFilteredIntersections<GL>(intersection_filter));
   }
 
-  /**
-   * \}
-   * \name These methods can be used to append another Walker.
-   * \{
-   */
-
-  /**
-   * \note The other_walker will be applied on the intersection of the given element_filter (intersection_filter) and
-   *       the filters of its ElementFunctors (IntersectionFunctors).
-   * \sa   WalkerWrapper
-   */
-  ThisType& append(Walker<GL>& other_walker,
-                   const ElementFilter<GL>& element_filter = ApplyOn::AllElements<GL>(),
-                   const IntersectionFilter<GL>& intersection_filter = ApplyOn::AllIntersections<GL>())
-  {
-    if (&other_walker == this)
-      DUNE_THROW(Common::Exceptions::you_are_using_this_wrong, "Do not append a Walker to itself!");
-    emplace_all(element_and_intersection_functor_wrappers_, other_walker, element_filter, intersection_filter);
-    return *this;
-  }
-
-  /**
-   * \note The other_walker will be applied on the intersection of the given element_filter (intersection_filter) and
-   *       the filters of its ElementFunctors (IntersectionFunctors).
-   * \sa   WalkerWrapper
-   */
-  ThisType& append(Walker<GL>& other_walker,
-                   const IntersectionFilter<GL>& intersection_filter,
-                   const ElementFilter<GL>& element_filter = new ApplyOn::AllElements<GL>())
-  {
-    if (&other_walker == this)
-      DUNE_THROW(Common::Exceptions::you_are_using_this_wrong, "Do not append a Walker to itself!");
-    emplace_all(element_and_intersection_functor_wrappers_, other_walker, element_filter, intersection_filter);
-    return *this;
-  }
-
-  /**
-   * \note The other_walker will be applied on the intersection of the given element_filter (intersection_filter) and
-   *       the filters of its ElementFunctors (IntersectionFunctors).
-   * \sa   WalkerWrapper
-   */
-  ThisType&
-  append(Walker<GL>& other_walker, ViewElementFunction element_filter, ViewIntersectionFunction intersection_filter)
-  {
-    if (&other_walker == this)
-      DUNE_THROW(Common::Exceptions::you_are_using_this_wrong, "Do not append a Walker to itself!");
-    emplace_all(element_and_intersection_functor_wrappers_,
-                other_walker,
-                ApplyOn::LambdaFilteredElements<GL>(element_filter),
-                ApplyOn::LambdaFilteredIntersections<GL>(intersection_filter));
-    return *this;
-  }
-
   /**
    * \}
    * \name These methods are required by ElementAndIntersectionFunctor.
@@ -575,8 +522,6 @@ private:
     } // .. walk elements
   } // ... walk_range(...)
 
-  friend class internal::WalkerWrapper<GridViewType>;
-
   GridViewType grid_view_;
   bool user_decided_agains_clearing_of_functors_;
   Common::PerThreadValue<std::list<std::shared_ptr<internal::ElementFunctorWrapper<GridViewType>>>>

dune/xt/grid/walker/wrapper.hh

@@ -189,67 +189,6 @@ private:
 }; // class ElementAndIntersectionFunctorWrapper
 
 
-/**
- * \brief To be used within the \sa Walker as internal storage type.
- * \note  Most likely you do not want to use this class directly, but instead append() a Walker to a Walker.
- */
-template <class GL>
-class WalkerWrapper : public ElementAndIntersectionFunctorWrapper<GL>
-{
-  using BaseType = ElementAndIntersectionFunctorWrapper<GL>;
-  using ThisType = WalkerWrapper<GL>;
-
-public:
-  using typename BaseType::ElementFilterType;
-  using typename BaseType::IntersectionFilterType;
-
-  /**
-   * \attention Takes ownership of element_filtr_ptr, do not delete manually!
-   * \attention Takes ownership of intersection_filtr_ptr, do not delete manually!
-   */
-  WalkerWrapper(Walker<GL>& walkr,
-                const ElementFilterType*&& element_filtr_ptr,
-                const IntersectionFilterType*&& intersection_filtr_ptr)
-    : BaseType(walkr,
-               new ApplyOn::LambdaFilteredElements<GL>([&](const auto& grid_layer, const auto& element) {
-                 if (restriction_element_filter_.access().contains(grid_layer, element)) {
-                   for (const auto& wrapper : walkr.element_functor_wrappers_) {
-                     if (wrapper->filter().contains(grid_layer, element))
-                       return true;
-                   }
-                   for (const auto& wrapper : walkr.element_and_intersection_functor_wrappers_) {
-                     if (wrapper->element_filter().contains(grid_layer, element))
-                       return true;
-                   }
-                   return false;
-                 } else
-                   return false;
-               }),
-               new ApplyOn::LambdaFilteredIntersections<GL>([&](const auto& grid_layer, const auto& intersection) {
-                 if (restriction_intersection_filter_.access().contains(grid_layer, intersection)) {
-                   for (const auto& wrapper : walkr.intersection_functor_wrappers_) {
-                     if (wrapper->filter().contains(grid_layer, intersection))
-                       return true;
-                   }
-                   for (const auto& wrapper : walkr.element_and_intersection_functor_wrappers_) {
-                     if (wrapper->intersection_filter().contains(grid_layer, intersection))
-                       return true;
-                   }
-                   return false;
-                 } else
-                   return false;
-               }))
-    , restriction_element_filter_(std::move(element_filtr_ptr))
-    , restriction_intersection_filter_(std::move(intersection_filtr_ptr))
-  {
-  }
-
-private:
-  const Common::ConstStorageProvider<ElementFilterType> restriction_element_filter_;
-  const Common::ConstStorageProvider<IntersectionFilterType> restriction_intersection_filter_;
-}; // class WalkerWrapper
-
-
 } // namespace internal
 } // namespace Grid
 } // namespace XT