tuple_basic.hpp

C++的一个好库。。。现在很流行

} // 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(BOOST_EXPLICIT_TEMPLATE_NON_TYPE(int, N)) {
    return boost::tuples::get<N>(*this);
  }

  template <int N>
  typename access_traits<
             typename element<N, self_type>::type
           >::const_type
  get(BOOST_EXPLICIT_TEMPLATE_NON_TYPE(int, N)) 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<null_type> {
  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);