Add deduction guides for TupleVector following those of std::tuple

CHANGELOG.md

@@ -5,6 +5,10 @@ SPDX-License-Identifier: LicenseRef-GPL-2.0-only-with-DUNE-exception
 
 # Master (will become release 2.11)
 
+## C++: Changelog
+
+- Add deduction guides to `TupleVector` analogous to `std::tuple`.
+
 # Release 2.10
 
 ## Dependencies

dune/common/test/hybridutilitiestest.cc

@@ -261,5 +261,33 @@ int main()
   constexpr auto numberTupleConstexpr = Dune::makeTupleVector(0.25, 2, 3);
   static_assert(sum(numberTupleConstexpr) == 5.25, "Wrong compile time sum!");
 
+  { // CTAD tests
+
+    auto tv0 = Dune::TupleVector{};
+
+    // test construction with values
+    static_assert(std::is_same_v<decltype(tv0),Dune::TupleVector<>>);
+    auto tv1 = Dune::TupleVector{1,2.0,3.0f,4u};
+    static_assert(std::is_same_v<decltype(tv1),Dune::TupleVector<int,double,float,unsigned int>>);
+    auto tv2 = Dune::TupleVector{std::tuple{1,2.0,3.0f,4u}};
+    static_assert(std::is_same_v<decltype(tv2),Dune::TupleVector<int,double,float,unsigned int>>);
+    auto tv3 = Dune::TupleVector{std::pair{1,2.0}};
+    static_assert(std::is_same_v<decltype(tv3),Dune::TupleVector<int,double>>);
+
+    // test construction with l-values
+    Dune::FieldVector<double,2> arg1{};
+    std::vector<float> arg2{};
+    auto tv4 = Dune::TupleVector{arg1,arg2};
+    static_assert(std::is_same_v<decltype(tv4),Dune::TupleVector<Dune::FieldVector<double,2>,std::vector<float>>>);
+
+    // test construction with allocators
+    auto tv5 = Dune::TupleVector{std::allocator_arg_t{}, std::allocator<float>{}, arg1, arg2};
+    static_assert(std::is_same_v<decltype(tv4),decltype(tv5)>);
+    auto tv6 = Dune::TupleVector{std::allocator_arg_t{}, std::allocator<float>{}, std::tuple{arg1, arg2}};
+    static_assert(std::is_same_v<decltype(tv4),decltype(tv6)>);
+    auto tv7 = Dune::TupleVector{std::allocator_arg_t{}, std::allocator<float>{}, std::pair{arg1, arg2}};
+    static_assert(std::is_same_v<decltype(tv4),decltype(tv7)>);
+  }
+
   return test.exit();
 }

dune/common/tuplevector.hh

@@ -35,13 +35,6 @@ class TupleVector : public std::tuple<T...>
 {
   using Base = std::tuple<T...>;
 
-  template<class... TT>
-  using TupleConstructorDetector = decltype(Base(std::declval<TT&&>()...));
-
-  template<class... TT>
-  using hasTupleConstructor = Dune::Std::is_detected<TupleConstructorDetector, TT...>;
-
-
 public:
 
   /** \brief Construct from a set of arguments
@@ -51,7 +44,7 @@ public:
    * list.
    */
   template<class... TT,
-    std::enable_if_t<hasTupleConstructor<TT...>::value, int> = 0>
+    class = std::void_t<decltype(Base(std::declval<TT&&>()...))>>
   constexpr TupleVector(TT&&... tt) :
     Base(std::forward<TT>(tt)...)
   {}
@@ -86,6 +79,29 @@ public:
   }
 };
 
+/// \name Deduction guides for TupleVector
+/// \relates TupleVector
+/// @{
+
+template<class... T>
+TupleVector(T...) -> TupleVector<T...>;
+
+template<class T1, class T2>
+TupleVector(std::pair<T1, T2>) -> TupleVector<T1, T2>;
+
+template<class... T>
+TupleVector(std::tuple<T...>) -> TupleVector<T...>;
+
+template <class Alloc, class... T>
+TupleVector(std::allocator_arg_t, Alloc, T...) -> TupleVector<T...>;
+
+template<class Alloc, class T1, class T2>
+TupleVector(std::allocator_arg_t, Alloc, std::pair<T1, T2>) -> TupleVector<T1, T2>;
+
+template<class Alloc, class... T>
+TupleVector(std::allocator_arg_t, Alloc, std::tuple<T...>) -> TupleVector<T...>;
+
+/// @}
 
 
 template<class... T>