tuple_basic.hpp 31.6 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980
//  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 BOOST_APPEND_EXPLICIT_TEMPLATE_NON_TYPE(int, N)) {
  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 BOOST_APPEND_EXPLICIT_TEMPLATE_NON_TYPE(int, N)) {
  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(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<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