text: //  tuple_basic.hpp -----------------------------------------------------
  
  // Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
  //
  // Distributed under the Boost Software License, Version 1.0. (See
  // accompanying file LICENSE_1_0.txt or copy at
  // http://www.boost.org/LICENSE_1_0.txt)
  
  // For more information, see http://www.boost.org
  
  // Outside help:
  // This and that, Gary Powell.
  // Fixed return types for get_head/get_tail
  // ( and other bugs ) per suggestion of Jens Maurer
  // simplified element type accessors + bug fix  (Jeremy Siek)
  // Several changes/additions according to suggestions by Douglas Gregor,
  // William Kempf, Vesa Karvonen, John Max Skaller, Ed Brey, Beman Dawes,
  // David Abrahams.
  
  // Revision history:
  // 2002 05 01 Hugo Duncan: Fix for Borland after Jaakko's previous changes
  // 2002 04 18 Jaakko: tuple element types can be void or plain function
  //                    types, as long as no object is created.
  //                    Tuple objects can no hold even noncopyable types
  //                    such as arrays.
  // 2001 10 22 John Maddock
  //      Fixes for Borland C++
  // 2001 08 30 David Abrahams
  //      Added default constructor for cons<>.
  // -----------------------------------------------------------------
  
  #ifndef BOOST_TUPLE_BASIC_HPP
  #define BOOST_TUPLE_BASIC_HPP
  
  
  #include <utility> // needed for the assignment from pair to tuple
  
  #include "boost/type_traits/cv_traits.hpp"
  #include "boost/type_traits/function_traits.hpp"
  #include "boost/utility/swap.hpp"
  
  #include "boost/detail/workaround.hpp" // needed for BOOST_WORKAROUND
  
  namespace boost {
  namespace tuples {
  
  // -- null_type --------------------------------------------------------
  struct null_type {};
  
  // a helper function to provide a const null_type type temporary
  namespace detail {
    inline const null_type cnull() { return null_type(); }
  
  
  // -- if construct ------------------------------------------------
  // Proposed by Krzysztof Czarnecki and Ulrich Eisenecker
  
  template <bool If, class Then, class Else> struct IF { typedef Then RET; };
  
  template <class Then, class Else> struct IF<false, Then, Else> {
    typedef Else RET;
  };
  
  } // end detail
  
  // - cons forward declaration -----------------------------------------------
  template <class HT, class TT> struct cons;
  
  
  // - tuple forward declaration -----------------------------------------------
  template <
    class T0 = null_type, class T1 = null_type, class T2 = null_type,
    class T3 = null_type, class T4 = null_type, class T5 = null_type,
    class T6 = null_type, class T7 = null_type, class T8 = null_type,
    class T9 = null_type>
  class tuple;
  
  // tuple_length forward declaration
  template<class T> struct length;
  
  
  
  namespace detail {
  
  // -- generate error template, referencing to non-existing members of this
  // template is used to produce compilation errors intentionally
  template<class T>
  class generate_error;
  
  template<int N>
  struct drop_front {
      template<class Tuple>
      struct apply {
          typedef BOOST_DEDUCED_TYPENAME drop_front<N-1>::BOOST_NESTED_TEMPLATE
              apply<Tuple> next;
          typedef BOOST_DEDUCED_TYPENAME next::type::tail_type type;
          static const type& call(const Tuple& tup) {
              return next::call(tup).tail;
          }
      };
  };
  
  template<>
  struct drop_front<0> {
      template<class Tuple>
      struct apply {
          typedef Tuple type;
          static const type& call(const Tuple& tup) {
              return tup;
          }
      };
  };
  
  } // end of namespace detail
  
  
  // -cons type accessors ----------------------------------------
  // typename tuples::element<N,T>::type gets the type of the
  // Nth element ot T, first element is at index 0
  // -------------------------------------------------------
  
  #ifndef BOOST_NO_CV_SPECIALIZATIONS
  
  template<int N, class T>
  struct element
  {
    typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
        apply<T>::type::head_type type;
  };
  
  template<int N, class T>
  struct element<N, const T>
  {
  private:
    typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
        apply<T>::type::head_type unqualified_type;
  public:
  #if BOOST_WORKAROUND(__BORLANDC__,<0x600)
    typedef const unqualified_type type;
  #else
    typedef BOOST_DEDUCED_TYPENAME boost::add_const<unqualified_type>::type type;
  #endif
  };
  #else // def BOOST_NO_CV_SPECIALIZATIONS
  
  namespace detail {
  
  template<int N, class T, bool IsConst>
  struct element_impl
  {
    typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
        apply<T>::type::head_type type;
  };
  
  template<int N, class T>
  struct element_impl<N, T, true /* IsConst */>
  {
    typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
        apply<T>::type::head_type unqualified_type;
    typedef const unqualified_type type;
  };
  
  } // end of namespace detail
  
  
  template<int N, class T>
  struct element:
    public detail::element_impl<N, T, ::boost::is_const<T>::value>
  {
  };
  
  #endif
  
  
  // -get function templates -----------------------------------------------
  // Usage: get<N>(aTuple)
  
  // -- some traits classes for get functions
  
  // access traits lifted from detail namespace to be part of the interface,
  // (Joel de Guzman's suggestion). Rationale: get functions are part of the
  // interface, so should the way to express their return types be.
  
  template <class T> struct access_traits {
    typedef const T& const_type;
    typedef T& non_const_type;
  
    typedef const typename boost::remove_cv<T>::type& parameter_type;
  
  // used as the tuple constructors parameter types
  // Rationale: non-reference tuple element types can be cv-qualified.
  // It should be possible to initialize such types with temporaries,
  // and when binding temporaries to references, the reference must
  // be non-volatile and const. 8.5.3. (5)
  };
  
  template <class T> struct access_traits<T&> {
  
    typedef T& const_type;
    typedef T& non_const_type;
  
    typedef T& parameter_type;
  };
  
  // get function for non-const cons-lists, returns a reference to the element
  
  template<int N, class HT, class TT>
  inline typename access_traits<
                    typename element<N, cons<HT, TT> >::type
                  >::non_const_type
  get(cons<HT, TT>& c) {
    typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
        apply<cons<HT, TT> > impl;
    typedef BOOST_DEDUCED_TYPENAME impl::type cons_element;
    return const_cast<cons_element&>(impl::call(c)).head;
  }
  
  // get function for const cons-lists, returns a const reference to
  // the element. If the element is a reference, returns the reference
  // as such (that is, can return a non-const reference)
  template<int N, class HT, class TT>
  inline typename access_traits<
                    typename element<N, cons<HT, TT> >::type
                  >::const_type
  get(const cons<HT, TT>& c) {
    typedef BOOST_DEDUCED_TYPENAME detail::drop_front<N>::BOOST_NESTED_TEMPLATE
        apply<cons<HT, TT> > impl;
    typedef BOOST_DEDUCED_TYPENAME impl::type cons_element;
    return impl::call(c).head;
  }
  
  // -- the cons template  --------------------------------------------------
  namespace detail {
  
  //  These helper templates wrap void types and plain function types.
  //  The reationale is to allow one to write tuple types with those types
  //  as elements, even though it is not possible to instantiate such object.
  //  E.g: typedef tuple<void> some_type; // ok
  //  but: some_type x; // fails
  
  template <class T> class non_storeable_type {
    non_storeable_type();
  };
  
  template <class T> struct wrap_non_storeable_type {
    typedef typename IF<
      ::boost::is_function<T>::value, non_storeable_type<T>, T
    >::RET type;
  };
  template <> struct wrap_non_storeable_type<void> {
    typedef non_storeable_type<void> type;
  };
  
  } // detail
  
  template <class HT, class TT>
  struct cons {
  
    typedef HT head_type;
    typedef TT tail_type;
  
    typedef typename
      detail::wrap_non_storeable_type<head_type>::type stored_head_type;
  
    stored_head_type head;
    tail_type tail;
  
    typename access_traits<stored_head_type>::non_const_type
    get_head() { return head; }
  
    typename access_traits<tail_type>::non_const_type
    get_tail() { return tail; }
  
    typename access_traits<stored_head_type>::const_type
    get_head() const { return head; }
  
    typename access_traits<tail_type>::const_type
    get_tail() const { return tail; }
  
    cons() : head(), tail() {}
    //  cons() : head(detail::default_arg<HT>::f()), tail() {}
  
    // the argument for head is not strictly needed, but it prevents
    // array type elements. This is good, since array type elements
    // cannot be supported properly in any case (no assignment,
    // copy works only if the tails are exactly the same type, ...)
  
    cons(typename access_traits<stored_head_type>::parameter_type h,
         const tail_type& t)
      : head (h), tail(t) {}
  
    template <class T1, class T2, class T3, class T4, class T5,
              class T6, class T7, class T8, class T9, class T10>
    cons( T1& t1, T2& t2, T3& t3, T4& t4, T5& t5,
          T6& t6, T7& t7, T8& t8, T9& t9, T10& t10 )
      : head (t1),
        tail (t2, t3, t4, t5, t6, t7, t8, t9, t10, detail::cnull())
        {}
  
    template <class T2, class T3, class T4, class T5,
              class T6, class T7, class T8, class T9, class T10>
    cons( const null_type& /*t1*/, T2& t2, T3& t3, T4& t4, T5& t5,
          T6& t6, T7& t7, T8& t8, T9& t9, T10& t10 )
      : head (),
        tail (t2, t3, t4, t5, t6, t7, t8, t9, t10, detail::cnull())
        {}
  
  
    template <class HT2, class TT2>
    cons( const cons<HT2, TT2>& u ) : head(u.head), tail(u.tail) {}
  
    template <class HT2, class TT2>
    cons& operator=( const cons<HT2, TT2>& u ) {
      head=u.head; tail=u.tail; return *this;
    }
  
    // must define assignment operator explicitly, implicit version is
    // illformed if HT is a reference (12.8. (12))
    cons& operator=(const cons& u) {
      head = u.head; tail = u.tail;  return *this;
    }
  
    template <class T1, class T2>
    cons& operator=( const std::pair<T1, T2>& u ) {
      BOOST_STATIC_ASSERT(length<cons>::value == 2); // check length = 2
      head = u.first; tail.head = u.second; return *this;
    }
  
    // get member functions (non-const and const)
    template <int N>
    typename access_traits<
               typename element<N, cons<HT, TT> >::type
             >::non_const_type
    get() {
      return boost::tuples::get<N>(*this); // delegate to non-member get
    }
  
    template <int N>
    typename access_traits<
               typename element<N, cons<HT, TT> >::type
             >::const_type
    get() const {
      return boost::tuples::get<N>(*this); // delegate to non-member get
    }
  };
  
  template <class HT>
  struct cons<HT, null_type> {
  
    typedef HT head_type;
    typedef null_type tail_type;
    typedef cons<HT, null_type> self_type;
  
    typedef typename
      detail::wrap_non_storeable_type<head_type>::type stored_head_type;
    stored_head_type head;
  
    typename access_traits<stored_head_type>::non_const_type
    get_head() { return head; }
  
    null_type get_tail() { return null_type(); }
  
    typename access_traits<stored_head_type>::const_type
    get_head() const { return head; }
  
    const null_type get_tail() const { return null_type(); }
  
    //  cons() : head(detail::default_arg<HT>::f()) {}
    cons() : head() {}
  
    cons(typename access_traits<stored_head_type>::parameter_type h,
         const null_type& = null_type())
      : head (h) {}
  
    template<class T1>
    cons(T1& t1, const null_type&, const null_type&, const null_type&,
         const null_type&, const null_type&, const null_type&,
         const null_type&, const null_type&, const null_type&)
    : head (t1) {}
  
    cons(const null_type&,
         const null_type&, const null_type&, const null_type&,
         const null_type&, const null_type&, const null_type&,
         const null_type&, const null_type&, const null_type&)
    : head () {}
  
    template <class HT2>
    cons( const cons<HT2, null_type>& u ) : head(u.head) {}
  
    template <class HT2>
    cons& operator=(const cons<HT2, null_type>& u )
    { head = u.head; return *this; }
  
    // must define assignment operator explicitely, implicit version
    // is illformed if HT is a reference
    cons& operator=(const cons& u) { head = u.head; return *this; }
  
    template <int N>
    typename access_traits<
               typename element<N, self_type>::type
              >::non_const_type
    get() {
      return boost::tuples::get<N>(*this);
    }
  
    template <int N>
    typename access_traits<
               typename element<N, self_type>::type
             >::const_type
    get() const {
      return boost::tuples::get<N>(*this);
    }
  
  };
  
  // templates for finding out the length of the tuple -------------------
  
  template<class T>
  struct length  {
    BOOST_STATIC_CONSTANT(int, value = 1 + length<typename T::tail_type>::value);
  };
  
  template<>
  struct length<tuple<> > {
    BOOST_STATIC_CONSTANT(int, value = 0);
  };
  
  template<>
  struct length<tuple<> const> {
    BOOST_STATIC_CONSTANT(int, value = 0);
  };
  
  template<>
  struct length<null_type> {
    BOOST_STATIC_CONSTANT(int, value = 0);
  };
  
  template<>
  struct length<null_type const> {
    BOOST_STATIC_CONSTANT(int, value = 0);
  };
  
  namespace detail {
  
  // Tuple to cons mapper --------------------------------------------------
  template <class T0, class T1, class T2, class T3, class T4,
            class T5, class T6, class T7, class T8, class T9>
  struct map_tuple_to_cons
  {
    typedef cons<T0,
                 typename map_tuple_to_cons<T1, T2, T3, T4, T5,
                                            T6, T7, T8, T9, null_type>::type
                > type;
  };
  
  // The empty tuple is a null_type
  template <>
  struct map_tuple_to_cons<null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type>
  {
    typedef null_type type;
  };
  
  } // end detail
  
  // -------------------------------------------------------------------
  // -- tuple ------------------------------------------------------
  template <class T0, class T1, class T2, class T3, class T4,
            class T5, class T6, class T7, class T8, class T9>
  
  class tuple :
    public detail::map_tuple_to_cons<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type
  {
  public:
    typedef typename
      detail::map_tuple_to_cons<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type inherited;
    typedef typename inherited::head_type head_type;
    typedef typename inherited::tail_type tail_type;
  
  
  // access_traits<T>::parameter_type takes non-reference types as const T&
    tuple() {}
  
    tuple(typename access_traits<T0>::parameter_type t0)
      : inherited(t0, detail::cnull(), detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull(), detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1)
      : inherited(t0, t1, detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull(), detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1,
          typename access_traits<T2>::parameter_type t2)
      : inherited(t0, t1, t2, detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1,
          typename access_traits<T2>::parameter_type t2,
          typename access_traits<T3>::parameter_type t3)
      : inherited(t0, t1, t2, t3, detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull(), detail::cnull(),
                  detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1,
          typename access_traits<T2>::parameter_type t2,
          typename access_traits<T3>::parameter_type t3,
          typename access_traits<T4>::parameter_type t4)
      : inherited(t0, t1, t2, t3, t4, detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull(), detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1,
          typename access_traits<T2>::parameter_type t2,
          typename access_traits<T3>::parameter_type t3,
          typename access_traits<T4>::parameter_type t4,
          typename access_traits<T5>::parameter_type t5)
      : inherited(t0, t1, t2, t3, t4, t5, detail::cnull(), detail::cnull(),
                  detail::cnull(), detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1,
          typename access_traits<T2>::parameter_type t2,
          typename access_traits<T3>::parameter_type t3,
          typename access_traits<T4>::parameter_type t4,
          typename access_traits<T5>::parameter_type t5,
          typename access_traits<T6>::parameter_type t6)
      : inherited(t0, t1, t2, t3, t4, t5, t6, detail::cnull(),
                  detail::cnull(), detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1,
          typename access_traits<T2>::parameter_type t2,
          typename access_traits<T3>::parameter_type t3,
          typename access_traits<T4>::parameter_type t4,
          typename access_traits<T5>::parameter_type t5,
          typename access_traits<T6>::parameter_type t6,
          typename access_traits<T7>::parameter_type t7)
      : inherited(t0, t1, t2, t3, t4, t5, t6, t7, detail::cnull(),
                  detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1,
          typename access_traits<T2>::parameter_type t2,
          typename access_traits<T3>::parameter_type t3,
          typename access_traits<T4>::parameter_type t4,
          typename access_traits<T5>::parameter_type t5,
          typename access_traits<T6>::parameter_type t6,
          typename access_traits<T7>::parameter_type t7,
          typename access_traits<T8>::parameter_type t8)
      : inherited(t0, t1, t2, t3, t4, t5, t6, t7, t8, detail::cnull()) {}
  
    tuple(typename access_traits<T0>::parameter_type t0,
          typename access_traits<T1>::parameter_type t1,
          typename access_traits<T2>::parameter_type t2,
          typename access_traits<T3>::parameter_type t3,
          typename access_traits<T4>::parameter_type t4,
          typename access_traits<T5>::parameter_type t5,
          typename access_traits<T6>::parameter_type t6,
          typename access_traits<T7>::parameter_type t7,
          typename access_traits<T8>::parameter_type t8,
          typename access_traits<T9>::parameter_type t9)
      : inherited(t0, t1, t2, t3, t4, t5, t6, t7, t8, t9) {}
  
  
    template<class U1, class U2>
    tuple(const cons<U1, U2>& p) : inherited(p) {}
  
    template <class U1, class U2>
    tuple& operator=(const cons<U1, U2>& k) {
      inherited::operator=(k);
      return *this;
    }
  
    template <class U1, class U2>
    tuple& operator=(const std::pair<U1, U2>& k) {
      BOOST_STATIC_ASSERT(length<tuple>::value == 2);// check_length = 2
      this->head = k.first;
      this->tail.head = k.second;
      return *this;
    }
  
  };
  
  // The empty tuple
  template <>
  class tuple<null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type, null_type>  :
    public null_type
  {
  public:
    typedef null_type inherited;
  };
  
  
  // Swallows any assignment   (by Doug Gregor)
  namespace detail {
  
  struct swallow_assign;
  typedef void (detail::swallow_assign::*ignore_t)();
  struct swallow_assign {
    swallow_assign(ignore_t(*)(ignore_t)) {}
    template<typename T>
    swallow_assign const& operator=(const T&) const {
      return *this;
    }
  };
  
  
  } // namespace detail
  
  // "ignore" allows tuple positions to be ignored when using "tie".
  inline detail::ignore_t ignore(detail::ignore_t) { return 0; }
  
  // ---------------------------------------------------------------------------
  // The call_traits for make_tuple
  // Honours the reference_wrapper class.
  
  // Must be instantiated with plain or const plain types (not with references)
  
  // from template<class T> foo(const T& t) : make_tuple_traits<const T>::type
  // from template<class T> foo(T& t) : make_tuple_traits<T>::type
  
  // Conversions:
  // T -> T,
  // references -> compile_time_error
  // reference_wrapper<T> -> T&
  // const reference_wrapper<T> -> T&
  // array -> const ref array
  
  
  template<class T>
  struct make_tuple_traits {
    typedef T type;
  
    // commented away, see below  (JJ)
    //  typedef typename IF<
    //  boost::is_function<T>::value,
    //  T&,
    //  T>::RET type;
  
  };
  
  // The is_function test was there originally for plain function types,
  // which can't be stored as such (we must either store them as references or
  // pointers). Such a type could be formed if make_tuple was called with a
  // reference to a function.
  // But this would mean that a const qualified function type was formed in
  // the make_tuple function and hence make_tuple can't take a function
  // reference as a parameter, and thus T can't be a function type.
  // So is_function test was removed.
  // (14.8.3. says that type deduction fails if a cv-qualified function type
  // is created. (It only applies for the case of explicitly specifying template
  // args, though?)) (JJ)
  
  template<class T>
  struct make_tuple_traits<T&> {
    typedef typename
       detail::generate_error<T&>::
         do_not_use_with_reference_type error;
  };
  
  // Arrays can't be stored as plain types; convert them to references.
  // All arrays are converted to const. This is because make_tuple takes its
  // parameters as const T& and thus the knowledge of the potential
  // non-constness of actual argument is lost.
  template<class T, int n>  struct make_tuple_traits <T[n]> {
    typedef const T (&type)[n];
  };
  
  template<class T, int n>
  struct make_tuple_traits<const T[n]> {
    typedef const T (&type)[n];
  };
  
  template<class T, int n>  struct make_tuple_traits<volatile T[n]> {
    typedef const volatile T (&type)[n];
  };
  
  template<class T, int n>
  struct make_tuple_traits<const volatile T[n]> {
    typedef const volatile T (&type)[n];
  };
  
  template<class T>
  struct make_tuple_traits<reference_wrapper<T> >{
    typedef T& type;
  };
  
  template<class T>
  struct make_tuple_traits<const reference_wrapper<T> >{
    typedef T& type;
  };
  
  template<>
  struct make_tuple_traits<detail::ignore_t(detail::ignore_t)> {
    typedef detail::swallow_assign type;
  };
  
  
  
  namespace detail {
  
  // a helper traits to make the make_tuple functions shorter (Vesa Karvonen's
  // suggestion)
  template <
    class T0 = null_type, class T1 = null_type, class T2 = null_type,
    class T3 = null_type, class T4 = null_type, class T5 = null_type,
    class T6 = null_type, class T7 = null_type, class T8 = null_type,
    class T9 = null_type
  >
  struct make_tuple_mapper {
    typedef
      tuple<typename make_tuple_traits<T0>::type,
            typename make_tuple_traits<T1>::type,
            typename make_tuple_traits<T2>::type,
            typename make_tuple_traits<T3>::type,
            typename make_tuple_traits<T4>::type,
            typename make_tuple_traits<T5>::type,
            typename make_tuple_traits<T6>::type,
            typename make_tuple_traits<T7>::type,
            typename make_tuple_traits<T8>::type,
            typename make_tuple_traits<T9>::type> type;
  };
  
  } // end detail
  
  // -make_tuple function templates -----------------------------------
  inline tuple<> make_tuple() {
    return tuple<>();
  }
  
  template<class T0>
  inline typename detail::make_tuple_mapper<T0>::type
  make_tuple(const T0& t0) {
    typedef typename detail::make_tuple_mapper<T0>::type t;
    return t(t0);
  }
  
  template<class T0, class T1>
  inline typename detail::make_tuple_mapper<T0, T1>::type
  make_tuple(const T0& t0, const T1& t1) {
    typedef typename detail::make_tuple_mapper<T0, T1>::type t;
    return t(t0, t1);
  }
  
  template<class T0, class T1, class T2>
  inline typename detail::make_tuple_mapper<T0, T1, T2>::type
  make_tuple(const T0& t0, const T1& t1, const T2& t2) {
    typedef typename detail::make_tuple_mapper<T0, T1, T2>::type t;
    return t(t0, t1, t2);
  }
  
  template<class T0, class T1, class T2, class T3>
  inline typename detail::make_tuple_mapper<T0, T1, T2, T3>::type
  make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3) {
    typedef typename detail::make_tuple_mapper<T0, T1, T2, T3>::type t;
    return t(t0, t1, t2, t3);
  }
  
  template<class T0, class T1, class T2, class T3, class T4>
  inline typename detail::make_tuple_mapper<T0, T1, T2, T3, T4>::type
  make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,
                    const T4& t4) {
    typedef typename detail::make_tuple_mapper<T0, T1, T2, T3, T4>::type t;
    return t(t0, t1, t2, t3, t4);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5>
  inline typename detail::make_tuple_mapper<T0, T1, T2, T3, T4, T5>::type
  make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,
                    const T4& t4, const T5& t5) {
    typedef typename detail::make_tuple_mapper<T0, T1, T2, T3, T4, T5>::type t;
    return t(t0, t1, t2, t3, t4, t5);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5, class T6>
  inline typename detail::make_tuple_mapper<T0, T1, T2, T3, T4, T5, T6>::type
  make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,
                    const T4& t4, const T5& t5, const T6& t6) {
    typedef typename detail::make_tuple_mapper
             <T0, T1, T2, T3, T4, T5, T6>::type t;
    return t(t0, t1, t2, t3, t4, t5, t6);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,
           class T7>
  inline typename detail::make_tuple_mapper<T0, T1, T2, T3, T4, T5, T6, T7>::type
  make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,
                    const T4& t4, const T5& t5, const T6& t6, const T7& t7) {
    typedef typename detail::make_tuple_mapper
             <T0, T1, T2, T3, T4, T5, T6, T7>::type t;
    return t(t0, t1, t2, t3, t4, t5, t6, t7);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,
           class T7, class T8>
  inline typename detail::make_tuple_mapper
    <T0, T1, T2, T3, T4, T5, T6, T7, T8>::type
  make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,
                    const T4& t4, const T5& t5, const T6& t6, const T7& t7,
                    const T8& t8) {
    typedef typename detail::make_tuple_mapper
             <T0, T1, T2, T3, T4, T5, T6, T7, T8>::type t;
    return t(t0, t1, t2, t3, t4, t5, t6, t7, t8);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,
           class T7, class T8, class T9>
  inline typename detail::make_tuple_mapper
    <T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type
  make_tuple(const T0& t0, const T1& t1, const T2& t2, const T3& t3,
                    const T4& t4, const T5& t5, const T6& t6, const T7& t7,
                    const T8& t8, const T9& t9) {
    typedef typename detail::make_tuple_mapper
             <T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type t;
    return t(t0, t1, t2, t3, t4, t5, t6, t7, t8, t9);
  }
  
  namespace detail {
  
  template<class T>
  struct tie_traits {
    typedef T& type;
  };
  
  template<>
  struct tie_traits<ignore_t(ignore_t)> {
    typedef swallow_assign type;
  };
  
  template<>
  struct tie_traits<void> {
    typedef null_type type;
  };
  
  template <
    class T0 = void, class T1 = void, class T2 = void,
    class T3 = void, class T4 = void, class T5 = void,
    class T6 = void, class T7 = void, class T8 = void,
    class T9 = void
  >
  struct tie_mapper {
    typedef
      tuple<typename tie_traits<T0>::type,
            typename tie_traits<T1>::type,
            typename tie_traits<T2>::type,
            typename tie_traits<T3>::type,
            typename tie_traits<T4>::type,
            typename tie_traits<T5>::type,
            typename tie_traits<T6>::type,
            typename tie_traits<T7>::type,
            typename tie_traits<T8>::type,
            typename tie_traits<T9>::type> type;
  };
  
  }
  
  // Tie function templates -------------------------------------------------
  template<class T0>
  inline typename detail::tie_mapper<T0>::type
  tie(T0& t0) {
    typedef typename detail::tie_mapper<T0>::type t;
    return t(t0);
  }
  
  template<class T0, class T1>
  inline typename detail::tie_mapper<T0, T1>::type
  tie(T0& t0, T1& t1) {
    typedef typename detail::tie_mapper<T0, T1>::type t;
    return t(t0, t1);
  }
  
  template<class T0, class T1, class T2>
  inline typename detail::tie_mapper<T0, T1, T2>::type
  tie(T0& t0, T1& t1, T2& t2) {
    typedef typename detail::tie_mapper<T0, T1, T2>::type t;
    return t(t0, t1, t2);
  }
  
  template<class T0, class T1, class T2, class T3>
  inline typename detail::tie_mapper<T0, T1, T2, T3>::type
  tie(T0& t0, T1& t1, T2& t2, T3& t3) {
    typedef typename detail::tie_mapper<T0, T1, T2, T3>::type t;
    return t(t0, t1, t2, t3);
  }
  
  template<class T0, class T1, class T2, class T3, class T4>
  inline typename detail::tie_mapper<T0, T1, T2, T3, T4>::type
  tie(T0& t0, T1& t1, T2& t2, T3& t3,
                    T4& t4) {
    typedef typename detail::tie_mapper<T0, T1, T2, T3, T4>::type t;
    return t(t0, t1, t2, t3, t4);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5>
  inline typename detail::tie_mapper<T0, T1, T2, T3, T4, T5>::type
  tie(T0& t0, T1& t1, T2& t2, T3& t3,
                    T4& t4, T5& t5) {
    typedef typename detail::tie_mapper<T0, T1, T2, T3, T4, T5>::type t;
    return t(t0, t1, t2, t3, t4, t5);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5, class T6>
  inline typename detail::tie_mapper<T0, T1, T2, T3, T4, T5, T6>::type
  tie(T0& t0, T1& t1, T2& t2, T3& t3,
                    T4& t4, T5& t5, T6& t6) {
    typedef typename detail::tie_mapper
             <T0, T1, T2, T3, T4, T5, T6>::type t;
    return t(t0, t1, t2, t3, t4, t5, t6);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,
           class T7>
  inline typename detail::tie_mapper<T0, T1, T2, T3, T4, T5, T6, T7>::type
  tie(T0& t0, T1& t1, T2& t2, T3& t3,
                    T4& t4, T5& t5, T6& t6, T7& t7) {
    typedef typename detail::tie_mapper
             <T0, T1, T2, T3, T4, T5, T6, T7>::type t;
    return t(t0, t1, t2, t3, t4, t5, t6, t7);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,
           class T7, class T8>
  inline typename detail::tie_mapper
    <T0, T1, T2, T3, T4, T5, T6, T7, T8>::type
  tie(T0& t0, T1& t1, T2& t2, T3& t3,
                    T4& t4, T5& t5, T6& t6, T7& t7,
                    T8& t8) {
    typedef typename detail::tie_mapper
             <T0, T1, T2, T3, T4, T5, T6, T7, T8>::type t;
    return t(t0, t1, t2, t3, t4, t5, t6, t7, t8);
  }
  
  template<class T0, class T1, class T2, class T3, class T4, class T5, class T6,
           class T7, class T8, class T9>
  inline typename detail::tie_mapper
    <T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type
  tie(T0& t0, T1& t1, T2& t2, T3& t3,
                    T4& t4, T5& t5, T6& t6, T7& t7,
                    T8& t8, T9& t9) {
    typedef typename detail::tie_mapper
             <T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>::type t;
    return t(t0, t1, t2, t3, t4, t5, t6, t7, t8, t9);
  }
  
  template <class T0, class T1, class T2, class T3, class T4,
            class T5, class T6, class T7, class T8, class T9>
  void swap(tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>& lhs,
            tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>& rhs);
  inline void swap(null_type&, null_type&) {}
  template<class HH>
  inline void swap(cons<HH, null_type>& lhs, cons<HH, null_type>& rhs) {
    ::boost::swap(lhs.head, rhs.head);
  }
  template<class HH, class TT>
  inline void swap(cons<HH, TT>& lhs, cons<HH, TT>& rhs) {
    ::boost::swap(lhs.head, rhs.head);
    ::boost::tuples::swap(lhs.tail, rhs.tail);
  }
  template <class T0, class T1, class T2, class T3, class T4,
            class T5, class T6, class T7, class T8, class T9>
  inline void swap(tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>& lhs,
            tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9>& rhs) {
    typedef tuple<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> tuple_type;
    typedef typename tuple_type::inherited base;
    ::boost::tuples::swap(static_cast<base&>(lhs), static_cast<base&>(rhs));
  }
  
  } // end of namespace tuples
  } // end of namespace boost
  
  
  #endif // BOOST_TUPLE_BASIC_HPP
  
  
  