diff --git a/include/rosa/deluxe/DeluxeTuple.hpp b/include/rosa/deluxe/DeluxeTuple.hpp
index 9a00e25..2fcd525 100644
--- a/include/rosa/deluxe/DeluxeTuple.hpp
+++ b/include/rosa/deluxe/DeluxeTuple.hpp
@@ -1,349 +1,358 @@
 //===-- rosa/deluxe/DeluxeTuple.hpp -----------------------------*- C++ -*-===//
 //
 //                                 The RoSA Framework
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file rosa/deluxe/DeluxeTuple.hpp
 ///
 /// \author David Juhasz (david.juhasz@tuwien.ac.at)
 ///
 /// \date 2019
 ///
 /// \brief Facilities for handling multiple input/output values for connections
 /// in the *deluxe interface*.
 ///
 /// \see \c rosa::deluxe::DeluxeContext
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef ROSA_DELUXE_DELUXETUPLE_HPP
 #define ROSA_DELUXE_DELUXETUPLE_HPP
 
 #include "rosa/support/sequence.hpp"
 #include "rosa/support/type_token.hpp"
 #include <ostream>
 #include <tuple>
 
 namespace rosa {
 namespace deluxe {
 
 /// A tuple to manage multiple input/output values in the *deluxe interface*.
 ///
 /// \tparam Ts types of elements of the tuple
 ///
 /// \note The template may be instantiated only with built-in types and the
 /// number of those type may not exceed the capacity of a \c rosa::Token.
 template <typename... Ts>
 struct DeluxeTuple : public std::tuple<Ts...> {
   // Statically enforce that the class template is instantiated only with
   // built-in types.
   STATIC_ASSERT((TypeListSubsetOf<TypeList<Ts...>, BuiltinTypes>::Value),
                 "not built-in types");
   // Statically enforce that the class template is instantiated with not too
   // many types.
   // \note Instantiation would fail on \c rosa::deluxe::DeluxeTuple::TT if there
   // are too any types; this assertion is for more readable error reporting.
   STATIC_ASSERT(sizeof...(Ts) <= token::MaxTokenizableListSize,
                 "Too many types");
 
   /// How many elements the instance has.
   static constexpr token_size_t Length = sizeof...(Ts);
 
   /// What types the class contains.
   ///
   /// Type information encoded as \c rosa::Token.
   static constexpr Token TT = TypeToken<Ts...>::Value;
 
   /// Default constructor, zero-initializes elements.
   DeluxeTuple(void) = default;
 
   /// Constructor, initializes the underlying \c std::tuple with lvalue
   /// references.
   ///
   /// \param Args value references to the values to store
   DeluxeTuple(const std::decay_t<Ts> &... Args) : std::tuple<Ts...>(Args...) {}
 
   /// Constructor, initializes the underlying \c std::tuple with rvalue
   /// references.
   ///
   /// \param Args rvalue references to the values to store
   DeluxeTuple(std::decay_t<Ts> &&... Args)
       : std::tuple<Ts...>(std::move(Args)...) {}
 
   /// Default copy-constructor.
   DeluxeTuple(const DeluxeTuple &) = default;
 
   /// Default move-constructor.
   DeluxeTuple(DeluxeTuple &&) = default;
 
   /// Default copy-assignment.
   DeluxeTuple &operator=(const DeluxeTuple &) = default;
 
   /// Default move-assignment.
   DeluxeTuple &operator=(DeluxeTuple &&) = default;
 
 private:
   /// Dumps \p this object to a given \c std::ostream.
   ///
   /// \note Provides implementation for \c rosa::deluxe::DeluxeTuple::dump.
   ///
   /// \tparam S0 Indices for accessing elements.
   ///
   /// \param [in,out] OS output stream to dump to
   ///
   /// \note The second argument provides indices statically as template
   /// arguments \p S0..., so its actual value is ignored.
   ///
   /// \pre Statically, \p S0... matches number of types \p this object was
   /// created: \code
   /// sizeof...(S0) == sizeof...(Ts)
   /// \endcode
   template <size_t... S0>
   void dump(std::ostream &OS, Seq<S0...>) const noexcept;
 
 public:
   /// Dumps \p this object to a given \c std::ostream.
   ///
   /// \param [in,out] OS output stream to dump to
   void dump(std::ostream &OS) const noexcept;
 };
 
 template <typename... Ts>
 template <size_t... S0>
 void DeluxeTuple<Ts...>::dump(std::ostream &OS, Seq<S0...>) const noexcept {
   STATIC_ASSERT(sizeof...(S0) == sizeof...(Ts), "inconsistent type arguments");
+  // Convert value to std::string with std::to_string except for a value of
+  // std::string that does not need conversion.
+  auto dump_to_string = [](const auto &V) {
+    if constexpr (std::is_same_v<std::decay_t<decltype(V)>, std::string>) {
+      return V;
+    } else {
+      return std::to_string(V);
+    }
+  };
   OS << "{";
-  (OS << ... << (" " + std::to_string(std::get<S0>(*this))));
+  (OS << ... << (" " + dump_to_string(std::get<S0>(*this))));
   OS << " }";
 }
 
 template <typename... Ts>
 void DeluxeTuple<Ts...>::dump(std::ostream &OS) const noexcept {
   dump(OS, seq_t<sizeof...(Ts)>());
 }
 
 /// Type alias for a \c rosa::deluxe::DeluxeTuple that contains no elements.
 using EmptyDeluxeTuple = DeluxeTuple<>;
 
 /// Template specialization for \c rosa::deluxe::EmptyDeluxeTuple.
 template <> struct DeluxeTuple<> : public std::tuple<> {
   /// How many elements the instance has.
   static constexpr token_size_t Length = 0;
 
   /// What types the class contains.
   ///
   /// Type information encoded as \c rosa::Token.
   static constexpr Token TT = TypeToken<>::Value;
 
   /// Constructor, initializes the underlying \c std::tuple.
   DeluxeTuple(void) : std::tuple<>() {}
 
   /// Default copy-constructor.
   DeluxeTuple(const DeluxeTuple &) = default;
 
   // Default move-constructor.
   DeluxeTuple(DeluxeTuple &&) = default;
 
   /// Default copy-assignment.
   DeluxeTuple &operator=(const DeluxeTuple &) = default;
 
   // Default move-assignment,
   DeluxeTuple &operator=(DeluxeTuple &&) = default;
 
   /// Dumps \p this object to a given \c std::ostream.
   ///
   /// \param [in,out] OS output stream to dump to
   static void dump(std::ostream &OS) noexcept;
 };
 
 /// Creates a \c rosa::deluxe::DeluxeTuple instance from the given lvalues
 /// references.
 ///
 /// \tparam Ts types of elements of the tuple
 ///
 /// \see \c rosa::deluxe::DeluxeTuple
 ///
 /// \param Args values to store in the tuple
 ///
 /// \return an instance of \c rosa::deluxe::DeluxeTuple<Ts...> with \p Args as
 /// elements
 template <typename... Ts>
 inline DeluxeTuple<Ts...> make_deluxe_tuple(const Ts &... Args) noexcept {
   return DeluxeTuple<Ts...>(Args...);
 }
 
 /// Creates a \c rosa::deluxe::DeluxeTuple instance from the given rvalue
 /// references.
 ///
 /// \tparam Ts types of elements of the tuple
 ///
 /// \see \c rosa::deluxe::DeluxeTuple
 ///
 /// \param Args values to store in the tuple
 ///
 /// \return an instance of \c rosa::deluxe::DeluxeTuple<Ts...> with \p Args as
 /// elements
 template <typename... Ts>
 inline DeluxeTuple<Ts...> make_deluxe_tuple(Ts&&... Args) noexcept {
   return DeluxeTuple<Ts...>(std::move(Args)...);
 }
 
 /// \defgroup UnwrapDeluxeTuple Implementation of
 /// rosa::deluxe::UnwrapDeluxeTuple
 ///
 /// \brief Unwraps element types from an instance of \c
 /// rosa::deluxe::DeluxeTuple into a \c rosa::TypeList
 ///
 /// Types can be unwrapped from a \c rosa::deluxe::DeluxeTuple instance as \code
 /// typename UnwrapDeluxeTuple<List>::Type
 /// \endcode
 ///
 /// For example, the following expression evaluates to `true`: \code
 /// std::is_same_v<typename UnwrapDeluxeTuple<DeluxeTuple<T1, T2>>::Type,
 ///                TypeList<T1, T2>>
 /// \endcode
 ///@{
 
 /// Declaration of the template.
 ///
 /// \tparam Tuple \c rosa::deluxe::DeluxeTuple to unwrap
 template <typename Tuple> struct UnwrapDeluxeTuple;
 
 /// Implementation of the template for \c rosa::deluxe::DeluxeTuple instances.
 template <typename... Ts> struct UnwrapDeluxeTuple<DeluxeTuple<Ts...>> {
   using Type = TypeList<Ts...>;
 };
 
 ///@}
 
 /// \defgroup TypeListUnwrapDeluxeTuple Implementation of
 /// \c rosa::deluxe::TypeListUnwrapDeluxeTuple
 ///
 /// \brief Unwraps element types from instances of \c
 /// rosa::deluxe::DeluxeTuple in a \c rosa::TypeList.
 ///
 /// Types can be unwrapped from \c rosa::deluxe::DeluxeTuple instances as \code
 /// typename TypeListUnwrapDeluxeTuple<List>::Type
 /// \endcode
 ///
 /// For example, the following expression evaluates to `true`: \code
 /// std::is_same_v<
 ///   typename TypeListUnwrapDeluxeTuple<TypeList<T0,
 ///                                               DeluxeTuple<T1, T2>,
 ///                                               T3>>::Type,
 ///   TypeList<T0, T1, T2, T3>>
 /// \endcode
 ///@{
 
 /// Declaration of the template.
 ///
 /// \tparam List \c rosa::TypeList to check
 template <typename List> struct TypeListUnwrapDeluxeTuple;
 
 /// Specialization for \c rosa::EmptyTypeList.
 template <> struct TypeListUnwrapDeluxeTuple<EmptyTypeList> {
   using Type = EmptyTypeList;
 };
 
 /// Specialization for the case when the first type in \p List is an instance of
 /// \c rosa::deluxe::DeluxeTuple.
 template <typename... As, typename... Ts>
 struct TypeListUnwrapDeluxeTuple<TypeList<DeluxeTuple<As...>, Ts...>> {
   using Type = typename TypeListConcat<
       typename UnwrapDeluxeTuple<DeluxeTuple<As...>>::Type,
       typename TypeListUnwrapDeluxeTuple<TypeList<Ts...>>::Type>::Type;
 };
 
 /// Implementation for a general first type in \p List.
 template <typename T, typename... Ts>
 struct TypeListUnwrapDeluxeTuple<TypeList<T, Ts...>> {
   using Type = typename TypeListPush<
       T, typename TypeListUnwrapDeluxeTuple<TypeList<Ts...>>::Type>::Type;
 };
 
 ///@}
 
 /// \defgroup IsDeluxeTuple Implementation of \c rosa::deluxe::IsDeluxeTuple
 ///
 /// \brief Tells if a type is an instance of \c rosa::deluxe::DeluxeTuple.
 ///
 /// Whether a type \c T is an instance of \c rosa::deluxe::DeluxeTuple can be
 /// checked as \code
 /// IsDeluxeTuple<T>::Value
 /// \endcode
 ///@{
 
 /// Declaration of the template.
 ///
 /// \tparam T type to check
 template <typename T> struct IsDeluxeTuple;
 
 /// Specialization for the case when the type is an instance of \c
 /// rosa::deluxe::DeluxeTuple.
 template <typename... Ts>
 struct IsDeluxeTuple<DeluxeTuple<Ts...>> {
   static constexpr bool Value = true;
 };
 
 /// Implementation for a general case of type \p T.
 template <typename T>
 struct IsDeluxeTuple {
   static constexpr bool Value = false;
 };
 
 ///@}
 
 /// \defgroup TypeListAllDeluxeTuple Implementation of
 /// \c rosa::deluxe::TypeListAllDeluxeTuple
 ///
 /// \brief Tells if all types in a \c rosa::TypeList is an instance of \c
 /// rosa::deluxe::DeluxeTuple.
 ///
 /// Whether a \c rosa::TypeList \c List contains instances of \c
 /// rosa::deluxe::DeluxeTuple only can be checked as \code
 /// TypeListAllDeluxeTuple<List>::Value
 /// \endcode
 ///@{
 
 /// Declaration of the template.
 ///
 /// \tparam List \c rosa::TypeList to check
 template <typename List> struct TypeListAllDeluxeTuple;
 
 /// Specialization for \c rosa::EmptyTypeList.
 template <> struct TypeListAllDeluxeTuple<EmptyTypeList> {
   static constexpr bool Value = true;
 };
 
 /// Implementation for the general case when there is at leasst one element in
 /// the list.
 template <typename T, typename... Ts>
 struct TypeListAllDeluxeTuple<TypeList<T, Ts...>> {
   static constexpr bool Value =
       IsDeluxeTuple<T>::Value && TypeListAllDeluxeTuple<TypeList<Ts...>>::Value;
 };
 
 ///@}
 
 } // End namespace deluxe
 } // End namespace rosa
 
 namespace std {
 
 /// Dumps a \c rosa::deluxe::Deluxe instance to a given \c std::ostream.
 ///
 /// \param [in,out] OS output stream to dump to
 /// \param Tuple \c rosa::deluxe::Deluxe to dump
 ///
 /// \return \p OS after dumping \p Tuple to it
 template <typename... Ts>
 ostream &operator<<(ostream &OS,
                     const rosa::deluxe::DeluxeTuple<Ts...> &Tuple) {
   Tuple.dump(OS);
   return OS;
 }
 
 } // End namespace std
 
 #endif // ROSA_DELUXE_DELUXETUPLE_HPP