introduce macros FWD and TYPEOF to reducine typing of std::forward and decltype

src/amdis/Assembler.hpp

@@ -138,7 +138,7 @@ namespace AMDiS
   template <class LocalContext, class Operator, class... Nodes>
   auto makeAssembler(Operator&& op, Nodes const&...)
   {
-    return Assembler<LocalContext, Underlying_t<Operator>, Nodes...>{std::forward<Operator>(op)};
+    return Assembler<LocalContext, Underlying_t<Operator>, Nodes...>{FWD(op)};
   }
 
 } // end namespace AMDiS

src/amdis/DataTransfer.inc.hpp

@@ -82,8 +82,7 @@ namespace AMDiS
       }
     };
 
-    using NodeDataTransferContainer = std::decay_t<decltype(
-      makeTreeContainer<Tree, NDT>(std::declval<const Tree&>(), NDT()))>;
+    using NodeDataTransferContainer = TYPEOF(makeTreeContainer<Tree, NDT>(std::declval<const Tree&>(), NDT()));
 
     // Returns the Node's NodeElementData
     struct NodeElementData

src/amdis/DirichletBC.hpp

@@ -41,16 +41,16 @@ namespace AMDiS
     template <class BM, class Values,
       REQUIRES(Concepts::Functor<Values, Range(Domain)>) >
     DirichletBC(BM&& boundaryManager, BoundaryType id, Values&& values)
-      : Super(std::forward<BM>(boundaryManager), id)
-      , values_(std::forward<Values>(values))
+      : Super(FWD(boundaryManager), id)
+      , values_(FWD(values))
     {}
 
     template <class Predicate, class Values,
       REQUIRES(Concepts::Functor<Predicate, bool(Domain)>),
       REQUIRES(Concepts::Functor<Values, Range(Domain)>)>
     DirichletBC(Predicate&& predicate, Values&& values)
-      : predicate_(std::forward<Predicate>(predicate))
-      , values_(std::forward<Values>(values))
+      : predicate_(FWD(predicate))
+      , values_(FWD(values))
     {}
 
     template <class Intersection>

src/amdis/GridFunctionOperator.hpp

@@ -70,7 +70,7 @@ namespace AMDiS
      **/
     template <class GF>
     GridFunctionOperatorBase(GF&& gridFct, int termOrder)
-      : gridFct_(std::forward<GF>(gridFct))
+      : gridFct_(FWD(gridFct))
       , termOrder_(termOrder)
     {}
 
@@ -80,7 +80,7 @@ namespace AMDiS
     {
       using ctype = typename Geometry::ctype;
       quadFactory_.emplace(
-        makeQuadratureFactory<ctype, LocalContext::mydimension, LocalFunction>(std::forward<PreQuadFactory>(pre)));
+        makeQuadratureFactory<ctype, LocalContext::mydimension, LocalFunction>(FWD(pre)));
     }
 
   protected:
@@ -157,14 +157,14 @@ namespace AMDiS
     template <class... Args,
       std::enable_if_t<Dune::Std::is_detected<Constructable, Transposed, Args...>::value, int> = 0>
     GridFunctionOperatorTransposed(Args&&... args)
-      : transposedOp_(std::forward<Args>(args)...)
+      : transposedOp_(FWD(args)...)
     {}
 
     /// Redirects the setQuadFactory call top the transposed operator
     template <class PreQuadFactory>
     void setQuadFactory(PreQuadFactory&& pre)
     {
-      transposedOp_.setQuadFactory(std::forward<PreQuadFactory>(pre));
+      transposedOp_.setQuadFactory(FWD(pre));
     }
 
   private:
@@ -210,9 +210,8 @@ namespace AMDiS
   template <class Tag, class Expr, class... QuadratureArgs>
   auto makeOperator(Tag tag, Expr&& expr, QuadratureArgs&&... args)
   {
-    auto pqf = makePreQuadratureFactory(std::forward<QuadratureArgs>(args)...);
-    using PreGridFctOp = PreGridFunctionOperator<Tag, std::decay_t<Expr>, decltype(pqf)>;
-    return PreGridFctOp{tag, std::forward<Expr>(expr), std::move(pqf)};
+    auto pqf = makePreQuadratureFactory(FWD(args)...);
+    return PreGridFunctionOperator<Tag, TYPEOF(expr), TYPEOF(pqf)>{tag, FWD(expr), std::move(pqf)};
   }
 
   /** @} **/
@@ -238,9 +237,8 @@ namespace AMDiS
   template <class Context, class Tag, class GF, class QF>
   auto makeGridFunctionOperator(Tag tag, GF&& gf, QF&& qf)
   {
-    using GridFctOp = GridFunctionOperator<Tag, Context, std::decay_t<GF>>;
-    GridFctOp gfo{tag, std::forward<GF>(gf)};
-    gfo.setQuadFactory(std::forward<QF>(qf));
+    GridFunctionOperator<Tag, Context, TYPEOF(gf)> gfo{tag, FWD(gf)};
+    gfo.setQuadFactory(FWD(qf));
     return gfo;
   }
 

src/amdis/Integrate.hpp

@@ -11,9 +11,9 @@ namespace AMDiS
     template <class GF, class GridView, class QuadProvider>
     auto integrateImpl(GF&& gf, GridView const& gridView, QuadProvider makeQuad)
     {
-      auto localFct = localFunction(std::forward<GF>(gf));
+      auto localFct = localFunction(FWD(gf));
 
-      using GridFct = std::decay_t<GF>;
+      using GridFct = remove_cvref_t<GF>;
       using Range = typename GridFct::Range;
       Range result(0);
 
@@ -34,7 +34,7 @@ namespace AMDiS
     template <class GF, class GridView, class QuadProvider>
     auto integrateImpl(GF&& gf, GridView const& gv, QuadProvider makeQuad, std::true_type)
     {
-      return integrateImpl(std::forward<GF>(gf), gv, makeQuad);
+      return integrateImpl(FWD(gf), gv, makeQuad);
     }
 
     template <class GF, class GV, class QP>
@@ -55,10 +55,10 @@ namespace AMDiS
   template <class Expr, class GridView>
   auto integrate(Expr&& expr, GridView const& gridView)
   {
-    auto&& gridFct = makeGridFunction(std::forward<Expr>(expr), gridView);
+    auto&& gridFct = makeGridFunction(FWD(expr), gridView);
 
     // test whether the gridFct model `Concepts::HasLocalFunctionOrder`
-    using GF = std::decay_t<decltype(gridFct)>;
+    using GF = TYPEOF(gridFct);
     static const bool expr_has_order = Concepts::HasLocalFunctionOrder<GF>;
     static_assert(expr_has_order,
       "Polynomial degree of expression can not be deduced. You need to provide an explicit value for the quadrature degree or a quadrature rule in `integrate()`.");
@@ -66,8 +66,7 @@ namespace AMDiS
     using Rules = Dune::QuadratureRules<typename GridView::ctype, GridView::dimension>;
     auto makeQuad = [](auto&& t, auto&& lf) { return Rules::rule(t, order(lf)); };
 
-    return Impl::integrateImpl(std::forward<decltype(gridFct)>(gridFct), gridView, makeQuad,
-      std::integral_constant<bool,expr_has_order>{});
+    return Impl::integrateImpl(FWD(gridFct), gridView, makeQuad, bool_<expr_has_order>);
   }
 
 
@@ -83,9 +82,8 @@ namespace AMDiS
     class QuadratureRule = Dune::QuadratureRule<typename GridView::ctype, GridView::dimension>>
   auto integrate(Expr&& expr, GridView const& gridView, QuadratureRule const& quad)
   {
-    auto&& gridFct = makeGridFunction(std::forward<Expr>(expr), gridView);
-    return Impl::integrateImpl(std::forward<decltype(gridFct)>(gridFct), gridView,
-      [&](auto&&, auto&&) { return quad; });
+    auto&& gridFct = makeGridFunction(FWD(expr), gridView);
+    return Impl::integrateImpl(FWD(gridFct), gridView, [&](auto&&, auto&&) { return quad; });
   }
 
 
@@ -102,8 +100,8 @@ namespace AMDiS
   {
     using Rules = Dune::QuadratureRules<typename GridView::ctype, GridView::dimension>;
 
-    auto&& gridFct = makeGridFunction(std::forward<Expr>(expr), gridView);
-    return Impl::integrateImpl(std::forward<decltype(gridFct)>(gridFct), gridView,
+    auto&& gridFct = makeGridFunction(FWD(expr), gridView);
+    return Impl::integrateImpl(FWD(gridFct), gridView,
       [&](auto const& type, auto&&) { return Rules::rule(type, degree, qt); });
   }
 

src/amdis/Marker.hpp

@@ -8,6 +8,7 @@
 #include <dune/grid/common/grid.hh>
 
 #include <amdis/common/ConceptsBase.hpp>
+#include <amdis/common/TypeTraits.hpp>
 
 #include <amdis/gridfunctions/GridFunctionConcepts.hpp>
 
@@ -382,7 +383,7 @@ namespace AMDiS
     template <class GF>
     GridFunctionMarker(std::string const& name, std::shared_ptr<Grid> const& grid, GF&& gf)
       : Super{name, grid}
-      , gridFct_{makeGridFunction(std::forward<GF>(gf), grid->leafGridView())}
+      , gridFct_{makeGridFunction(FWD(gf), grid->leafGridView())}
     {}
 
     /// \brief Implementation of \ref Marker::markElement. Does nothing since marking is
@@ -402,11 +403,10 @@ namespace AMDiS
 
 #if DUNE_HAVE_CXX_CLASS_TEMPLATE_ARGUMENT_DEDUCTION
   // Deduction guide for GridFunctionMarker class
-  template <class Grid, class PreGridFct>
-  GridFunctionMarker(std::string const& name, std::shared_ptr<Grid> const& grid,
-                     PreGridFct&& preGridFct)
+  template <class Grid, class GF>
+  GridFunctionMarker(std::string const& name, std::shared_ptr<Grid> const& grid, GF&& gf)
     -> GridFunctionMarker<Grid,
-          std::decay_t<decltype(makeGridFunction(std::forward<PreGridFct>(preGridFct), grid->leafGridView()))>>;
+          TYPEOF( makeGridFunction(FWD(gf), grid->leafGridView()) )>;
 #endif
 
   // Generator function for GridFunctionMarker class
@@ -414,9 +414,8 @@ namespace AMDiS
   auto makeGridFunctionMarker(std::string const& name, std::shared_ptr<Grid> const& grid,
                               PreGridFct&& preGridFct)
   {
-    auto gridFct = makeGridFunction(std::forward<PreGridFct>(preGridFct), grid->leafGridView());
-    using GridFct = decltype(gridFct);
-    return GridFunctionMarker<Grid,GridFct>{name, grid, gridFct};
+    auto gridFct = makeGridFunction(FWD(preGridFct), grid->leafGridView());
+    return GridFunctionMarker<Grid,TYPEOF(gridFct)>{name, grid, std::move(gridFct)};
   }
 
 } // end namespace AMDiS

src/amdis/OperatorList.hpp

@@ -76,19 +76,19 @@ namespace AMDiS
       template <class Op>
       void push(tag::element_operator<Element>, Op&& op)
       {
-        element_.emplace_back(std::forward<Op>(op));
+        element_.emplace_back(FWD(op));
       }
 
       template <class Op>
       void push(tag::intersection_operator<Intersection>, Op&& op)
       {
-        intersection_.emplace_back(std::forward<Op>(op));
+        intersection_.emplace_back(FWD(op));
       }
 
       template <class Op>
       void push(tag::boundary_operator<Intersection> b, Op&& op)
       {
-        boundary_.push_back({std::forward<Op>(op), b});
+        boundary_.push_back({FWD(op), b});
       }
 
 

src/amdis/Output.hpp

@@ -22,6 +22,8 @@
 #include <fmt/core.h>
 #include <fmt/ostream.h>
 
+#include <amdis/common/TypeTraits.hpp>
+
 /**
  * \def AMDIS_ENABLE_MSG_DBG
  * \brief The preprocessor constant enables the functions \ref AMDiS::MSG_DBG
@@ -66,12 +68,12 @@ namespace AMDiS
       MPI_Comm_size(MPI_COMM_WORLD, &num_ranks);
       if (num_ranks > 1 && rank == 0) {
         out << "[0] ";
-        fmt::print(out, std::forward<Args>(args)...);
+        fmt::print(out, FWD(args)...);
       } else if (num_ranks == 1) {
-        fmt::print(out, std::forward<Args>(args)...);
+        fmt::print(out, FWD(args)...);
       }
 #else
-      fmt::print(out, std::forward<Args>(args)...);
+      fmt::print(out, FWD(args)...);
 #endif
       return out;
     }
@@ -89,7 +91,7 @@ namespace AMDiS
   template <class... Args>
   void msg(Args&&... args)
   {
-    Impl::msg(std::cout, std::forward<Args>(args)...) << std::endl;
+    Impl::msg(std::cout, FWD(args)...) << std::endl;
   }
 
 
@@ -103,7 +105,7 @@ namespace AMDiS
   template <class... Args>
   void msg_(Args&&... args)
   {
-    Impl::msg(std::cout, std::forward<Args>(args)...);
+    Impl::msg(std::cout, FWD(args)...);
   }
 
 
@@ -117,14 +119,14 @@ namespace AMDiS
   void error_exit(Args&&... args)
   {
 #ifdef AMDIS_NO_THROW
-    Impl::msg(std::cerr << "ERROR: ", std::forward<Args>(args)...) << std::endl;
+    Impl::msg(std::cerr << "ERROR: ", FWD(args)...) << std::endl;
     #ifndef NDEBUG
       assert(false);
     #else
       std::exit(EXIT_FAILURE);
     #endif
 #else
-    throw std::runtime_error( std::string("ERROR: ") + fmt::format(std::forward<Args>(args)...));
+    throw std::runtime_error( std::string("ERROR: ") + fmt::format(FWD(args)...));
 #endif
   }
 
@@ -141,14 +143,14 @@ namespace AMDiS
   template <class... Args>
   void test_exit(bool condition, Args&&... args)
   {
-    if (!condition) { error_exit(std::forward<Args>(args)...); }
+    if (!condition) { error_exit(FWD(args)...); }
   }
 
 
   template <class... Args>
   void warning(Args&&... args)
   {
-    Impl::msg(std::cout << "WARNING: ", std::forward<Args>(args)...) << std::endl;
+    Impl::msg(std::cout << "WARNING: ", FWD(args)...) << std::endl;
   }
 
 
@@ -161,7 +163,7 @@ namespace AMDiS
   template <class... Args>
   void test_warning(bool condition, Args&&... args)
   {
-    if (!condition) { warning(std::forward<Args>(args)...); }
+    if (!condition) { warning(FWD(args)...); }
   }
 
 
@@ -172,7 +174,7 @@ namespace AMDiS
    * \ref AMDIS_ENABLE_MSG_DBG is set to 1, otherwise the function is empty.
    **/
   template <class... Args>
-  void msg_dbg(Args&&... args) { msg(std::forward<Args>(args)...); }
+  void msg_dbg(Args&&... args) { msg(FWD(args)...); }
 
 
   /// \brief call assert_msg, in debug mode only
@@ -183,7 +185,7 @@ namespace AMDiS
   template <class... Args>
   void test_exit_dbg(bool condition, Args&&... args)
   {
-    test_exit(condition, std::forward<Args>(args)...);
+    test_exit(condition, FWD(args)...);
   }
 #else
   template <class... Args>

src/amdis/PeriodicBC.hpp

@@ -54,7 +54,7 @@ namespace AMDiS
   public:
     template <class BM>
     PeriodicBC(BM&& boundaryManager, BoundaryType id, FaceTrafo faceTrafo)
-      : Super(std::forward<BM>(boundaryManager), id)
+      : Super(FWD(boundaryManager), id)
       , faceTrafo_(std::move(faceTrafo))
     {}
 

src/amdis/PeriodicBC.inc.hpp

@@ -202,7 +202,7 @@ coords(Node const& tree, std::vector<std::size_t> const& localIndices) const
     auto geometry = node.element().geometry();
 
     auto const& localInterpol = node.finiteElement().localInterpolation();
-    using FiniteElement = std::decay_t<decltype(node.finiteElement())>;
+    using FiniteElement = TYPEOF(node.finiteElement());
     using DomainType = typename FiniteElement::Traits::LocalBasisType::Traits::DomainType;
     using RangeType = typename FiniteElement::Traits::LocalBasisType::Traits::RangeType;
 

src/amdis/common/ClonablePtr.hpp

+#pragma once
+
+#include <memory>
+#include <utility>
+
+#include <amdis/common/Utility.hpp>
+
+namespace AMDiS
+{
+  // A pointer class that deletes only when owning the pointer
+  template <class T>
+  class ClonablePtr
+  {
+  private:
+    struct alloc_tag {}; ///< hidden helper struct, used by \ref make
+
+  public:
+    using Self = ClonablePtr;
+    using element_type = T;
+
+    /// Default constructor, creates a non-owned nullptr
+    ClonablePtr() = default;
+
+    /// Constructor from pointer. Can only be used via make method,
+    /// Transfers ownership.
+    ClonablePtr(owner<T>* p, alloc_tag) noexcept
+      : p(p)
+      , is_owner(true)
+    {}
+
+    /// Constructor from reference
+    explicit ClonablePtr(T& ref) noexcept
+      : p(&ref)
+      , is_owner(false)
+    {}
+
+    /// Constructor from std::unique_ptr
+    explicit ClonablePtr(std::unique_ptr<T>& ptr)
+      : p(ptr.release())
+      , is_owner(true)
+    {}
+
+    explicit ClonablePtr(std::unique_ptr<T>&& ptr)
+      : p(ptr.release())
+      , is_owner(true)
+    {}
+
+    /// Destructor, deletes in case of owner only
+    ~ClonablePtr() noexcept
+    {
+      if (is_owner)
+        delete p;
+    }
+
+    /// Copy constructor, creates a clone of the pointed to object
+    ClonablePtr(Self const& that) noexcept( std::is_nothrow_copy_constructible<T>::value )
+      : p(new T(*that.p))
+      , is_owner(true)
+    {}
+
+    /// Move constructor, copies the pointer only.
+    ClonablePtr(Self&& that) noexcept
+      : p(that.p)
+      , is_owner(that.is_owner)
+    {
+      that.p = nullptr;
+      that.is_owner = false;
+    }
+
+    /// Copy and move assignment operator, using the copy-and-swap idiom
+    Self& operator=(Self that) noexcept
+    {
+      swap(that);
+      return *this;
+    }
+
+    /// Factory method. creates a new Object of type T and stores the pointer.
+    template <class... Args>
+    static Self make(Args&&... args)
+      noexcept( std::is_nothrow_constructible<T, remove_cvref_t<Args>...>::value )
+    {
+      return {new T(FWD(args)...), Self::alloc_tag()};
+    }
+
+    /// Access-method by dereferencing
+    T& operator*() const noexcept
+    {
+      return *p;
+    }
+
+    /// Access-method by pointer access
+    T* operator->() const noexcept
+    {
+      return p;
+    }
+
+    /// retrieve the underlying pointer
+    T* get() const noexcept
+    {
+      return p;
+    }
+
+    /// Test whether pointer is NULL
+    operator bool() const noexcept
+    {
+      return !(p == NULL);
+    }
+
+    void swap(Self& that) noexcept
+    {
+      using std::swap;
+      swap(p, that.p);
+      swap(is_owner, that.is_owner);
+    }
+
+  private:
+    T* p = nullptr;		///< managed pointer
+    bool is_owner = false;	///< true, if class is owner of pointer, false otherwise
+  };
+
+  template <class T>
+  void swap(ClonablePtr<T>& a, ClonablePtr<T>& b) noexcept
+  {
+    a.swap(b);
+  }
+
+} // end namespace AMDiS

src/amdis/common/Concepts.hpp

@@ -52,7 +52,7 @@ namespace AMDiS
       struct Callable
       {
         template <class F, class... Args>
-        auto requires_(F&& f, Args&&... args) -> decltype( f(std::forward<Args>(args)...));
+        auto requires_(F&& f, Args&&... args) -> decltype( f(FWD(args)...));
       };
 
       // idx[0]

src/amdis/common/ConcurrentCache.hpp

@@ -125,8 +125,7 @@ namespace AMDiS
     template <class F, class... Args>
     static data_type const& get_or_init(key_type const& key, F&& f, Args&&... args)
     {
-      return impl(std::is_default_constructible<data_type>{},
-        key, std::forward<F>(f), std::forward<Args>(args)...);
+      return impl(std::is_default_constructible<data_type>{}, key, FWD(f), FWD(args)...);
     }
 
   private:
@@ -140,7 +139,7 @@ namespace AMDiS
       data_type empty;
       auto it = cached_data.emplace(key, std::move(empty));
       if (it.second) {
-        data_type data = f(key, std::forward<Args>(args)...);
+        data_type data = f(key, FWD(args)...);
         it.first->second = std::move(data);
       }
       return it.first->second;
@@ -157,7 +156,7 @@ namespace AMDiS
       if (it != cached_data.end())
         return it->second;
       else {
-        data_type data = f(key, std::forward<Args>(args)...);
+        data_type data = f(key, FWD(args)...);
         auto it = cached_data.emplace(key, std::move(data));
         return it.first->second;
       }
@@ -192,7 +191,7 @@ namespace AMDiS
         return it->second;
       else {
         read_lock.unlock();
-        data_type data = f(key, std::forward<Args>(args)...);
+        data_type data = f(key, FWD(args)...);
         std::unique_lock<mutex_type> write_lock(access_mutex);
         auto new_it = cached_data.emplace(key, std::move(data));
         return new_it.first->second;
@@ -224,7 +223,7 @@ namespace AMDiS
       static_assert(Dune::Std::is_callable<F(key_type, Args...), data_type>::value,
         "Functor F must have the signature data_type(key_type, Args...)");
 
-      return ConcurrentCache::get_or_init(key, std::forward<F>(f), std::forward<Args>(args)...);
+      return ConcurrentCache::get_or_init(key, FWD(f), FWD(args)...);
     }
   };
 

src/amdis/common/FieldTraits.hpp

+#pragma once
+
+#include <dune/common/ftraits.hh>
+
+#include <amdis/common/Utility.hpp>
+
+namespace AMDiS
+{
+  template <class... T>
+  struct CommonFieldTraits
+  {
+    using field_type = std::common_type_t<typename Dune::FieldTraits<T>::field_type...>;
+    using real_type = std::common_type_t<typename Dune::FieldTraits<T>::real_type...>;
+  };
+
+} // end namespace AMDiS

src/amdis/common/MultiTypeMatrix.hpp

@@ -56,7 +56,7 @@ namespace AMDiS
     template <class... Rows_,
       REQUIRES( Concepts::Similar<Types<Rows...>, Types<Rows_...>> )>
     MultiTypeMatrix(Rows_&&... rows)
-      : Super(std::forward<Rows_>(rows)...)
+      : Super(FWD(rows)...)
     {}
 
     /// Default construction of tuple of FieldVectors

src/amdis/common/MultiTypeVector.hpp

@@ -49,7 +49,7 @@ namespace AMDiS
     template <class... FV_,
       REQUIRES( Concepts::Similar<Types<FV...>, Types<FV_...>> )>
     MultiTypeVector(FV_&&... fv)
-      : Super(std::forward<FV_>(fv)...)
+      : Super(FWD(fv)...)
     {}
 
     /// Default construction of tuple of FieldVectors

src/amdis/common/ScalarTypes.hpp

+#pragma once
+
+// std c++ headers
+#include <type_traits>
+#include <amdis/common/Utility.hpp>
+
+namespace AMDiS
+{
+  namespace Traits
+  {
+    template <class T>
+    struct IsIntegral
+        : public std::is_integral<remove_cvref_t<T>> {};
+
+    template <class T>
+    struct IsArithmetic
+        : public std::is_arithmetic<remove_cvref_t<T>> {};
+
+  } // end namespace traits
+
+  namespace Concepts
+  {
+    /** \addtogroup Concepts
+     *  @{
+     **/
+
+    /// \brief The types following the std type-trait \ref std::is_integral are
+    /// categorized as *integral types*.
+    template <class T>
+    constexpr bool Integral = Traits::IsIntegral<T>::value;
+
+    /// \brief The types following the std type-trait \ref std::is_arithmetic are
+    /// categorized as *arithmetic types*.
+    template <class T>
+    constexpr bool Arithmetic = Traits::IsArithmetic<T>::value;
+
+    /** @} **/
+
+  } // end namespace Concepts
+
+} // end namespace AMDiS

src/amdis/common/StaticSize.hpp

@@ -79,10 +79,10 @@ namespace AMDiS
 
   /// Get the number of elements in a tuple / pair / array / ...
   template <class T>
-  constexpr std::size_t Size_v = Impl::SizeImpl<std::decay_t<T>>::value;
+  constexpr std::size_t Size_v = Impl::SizeImpl<remove_cvref_t<T>>::value;