tuple_basic.hpp

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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& 
  explicit tuple(
    typename access_traits<T0>::parameter_type t0 
      = detail::default_arg<T0>::f(),
    typename access_traits<T1>::parameter_type t1 
      = detail::default_arg<T1>::f(),
    typename access_traits<T2>::parameter_type t2 
      = detail::default_arg<T2>::f(),
    typename access_traits<T3>::parameter_type t3 
      = detail::default_arg<T3>::f(),
    typename access_traits<T4>::parameter_type t4 
      = detail::default_arg<T4>::f(),
    typename access_traits<T5>::parameter_type t5 
      = detail::default_arg<T5>::f(),
    typename access_traits<T6>::parameter_type t6 
      = detail::default_arg<T6>::f(),
    typename access_traits<T7>::parameter_type t7 
      = detail::default_arg<T7>::f(),
    typename access_traits<T8>::parameter_type t8 
      = detail::default_arg<T8>::f(),
    typename access_traits<T9>::parameter_type t9 
      = detail::default_arg<T9>::f())

        : 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 {
      
  template<typename T>
  swallow_assign& operator=(const T&) {
    return *this;
  }
};

} // namespace detail

// "ignore" allows tuple positions to be ignored when using "tie". 
namespace {
 detail::swallow_assign ignore;
}

// ---------------------------------------------------------------------------
// 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;
};




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); 
}



// Tie function templates -------------------------------------------------
template<class T1>
inline tuple<T1&> tie(T1& t1) {
  return tuple<T1&> (t1);
}

template<class T1, class T2>
inline tuple<T1&, T2&> tie(T1& t1, T2& t2) {
  return tuple<T1&, T2&> (t1, t2);
}

template<class T1, class T2, class T3>
inline tuple<T1&, T2&, T3&> tie(T1& t1, T2& t2, T3& t3) {
  return tuple<T1&, T2&, T3&> (t1, t2, t3);
}

template<class T1, class T2, class T3, class T4>
inline tuple<T1&, T2&, T3&, T4&> tie(T1& t1, T2& t2, T3& t3, T4& t4) {
  return tuple<T1&, T2&, T3&, T4&> (t1, t2, t3, t4);
}

template<class T1, class T2, class T3, class T4, class T5>
inline tuple<T1&, T2&, T3&, T4&, T5&> 
tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5) {
  return tuple<T1&, T2&, T3&, T4&, T5&> (t1, t2, t3, t4, t5);
}

template<class T1, class T2, class T3, class T4, class T5, class T6>
inline tuple<T1&, T2&, T3&, T4&, T5&, T6&> 
tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6) {
  return tuple<T1&, T2&, T3&, T4&, T5&, T6&> (t1, t2, t3, t4, t5, t6);
}

template<class T1, class T2, class T3, class T4, class T5, class T6, class T7>
inline tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&> 
tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7) {
  return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&> (t1, t2, t3, t4, t5, t6, t7);
}

template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, 
         class T8>
inline tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&> 
tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7, T8& t8) {
  return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&> 
           (t1, t2, t3, t4, t5, t6, t7, t8);
}

template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, 
         class T8, class T9>
inline tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&> 
tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7, T8& t8, 
           T9& t9) {
  return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&> 
            (t1, t2, t3, t4, t5, t6, t7, t8, t9);
}

template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, 
         class T8, class T9, class T10>
inline tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&, T10&> 
tie(T1& t1, T2& t2, T3& t3, T4& t4, T5& t5, T6& t6, T7& t7, T8& t8, 
           T9& t9, T10& t10) {
  return tuple<T1&, T2&, T3&, T4&, T5&, T6&, T7&, T8&, T9&, T10&> 
           (t1, t2, t3, t4, t5, t6, t7, t8, t9, t10);
}

} // end of namespace tuples
} // end of namespace boost


#endif	// BOOST_TUPLE_BASIC_HPP