ceph/src/boost/boost/concept_archetype.hpp

   1 //
   2 // (C) Copyright Jeremy Siek 2000.
   3 // Distributed under the Boost Software License, Version 1.0. (See
   4 // accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Revision History:
   8 //
   9 //   17 July  2001: Added const to some member functions. (Jeremy Siek)
  10 //   05 May   2001: Removed static dummy_cons object. (Jeremy Siek)
  11
  12 // See http://www.boost.org/libs/concept_check for documentation.
  13
  14 #ifndef BOOST_CONCEPT_ARCHETYPES_HPP
  15 #define BOOST_CONCEPT_ARCHETYPES_HPP
  16
  17 #include <boost/config.hpp>
  18 #include <boost/config/workaround.hpp>
  19 #include <functional>
  20 #include <iterator>  // iterator tags
  21 #include <cstddef>   // std::ptrdiff_t
  22
  23 namespace boost {
  24
  25   //===========================================================================
  26   // Basic Archetype Classes
  27
  28   namespace detail {
  29     class dummy_constructor { };
  30   }
  31
  32   // A type that models no concept. The template parameter
  33   // is only there so that null_archetype types can be created
  34   // that have different type.
  35   template <class T = int>
  36   class null_archetype {
  37   private:
  38     null_archetype() { }
  39     null_archetype(const null_archetype&) { }
  40     null_archetype& operator=(const null_archetype&) { return *this; }
  41   public:
  42     null_archetype(detail::dummy_constructor) { }
  43 #ifndef __MWERKS__
  44     template <class TT>
  45     friend void dummy_friend(); // just to avoid warnings
  46 #endif
  47   };
  48
  49   // This is a helper class that provides a way to get a reference to
  50   // an object. The get() function will never be called at run-time
  51   // (nothing in this file will) so this seemingly very bad function
  52   // is really quite innocent. The name of this class needs to be
  53   // changed.
  54   template <class T>
  55   class static_object
  56   {
  57   public:
  58       static T& get()
  59       {
  60 #if BOOST_WORKAROUND(BOOST_BORLANDC, BOOST_TESTED_AT(0x564))
  61           return *reinterpret_cast<T*>(0);
  62 #else
  63           static char d[sizeof(T)];
  64           return *reinterpret_cast<T*>(d);
  65 #endif
  66       }
  67   };
  68
  69   template <class Base = null_archetype<> >
  70   class default_constructible_archetype : public Base {
  71   public:
  72     default_constructible_archetype()
  73       : Base(static_object<detail::dummy_constructor>::get()) { }
  74     default_constructible_archetype(detail::dummy_constructor x) : Base(x) { }
  75   };
  76
  77   template <class Base = null_archetype<> >
  78   class assignable_archetype : public Base {
  79     assignable_archetype() { }
  80     assignable_archetype(const assignable_archetype&) { }
  81   public:
  82     assignable_archetype& operator=(const assignable_archetype&) {
  83       return *this;
  84     }
  85     assignable_archetype(detail::dummy_constructor x) : Base(x) { }
  86   };
  87
  88   template <class Base = null_archetype<> >
  89   class copy_constructible_archetype : public Base {
  90   public:
  91     copy_constructible_archetype()
  92       : Base(static_object<detail::dummy_constructor>::get()) { }
  93     copy_constructible_archetype(const copy_constructible_archetype&)
  94       : Base(static_object<detail::dummy_constructor>::get()) { }
  95     copy_constructible_archetype(detail::dummy_constructor x) : Base(x) { }
  96   };
  97
  98   template <class Base = null_archetype<> >
  99   class sgi_assignable_archetype : public Base {
 100   public:
 101     sgi_assignable_archetype(const sgi_assignable_archetype&)
 102       : Base(static_object<detail::dummy_constructor>::get()) { }
 103     sgi_assignable_archetype& operator=(const sgi_assignable_archetype&) {
 104       return *this;
 105     }
 106     sgi_assignable_archetype(const detail::dummy_constructor& x) : Base(x) { }
 107   };
 108
 109   struct default_archetype_base {
 110     default_archetype_base(detail::dummy_constructor) { }
 111   };
 112
 113   // Careful, don't use same type for T and Base. That results in the
 114   // conversion operator being invalid.  Since T is often
 115   // null_archetype, can't use null_archetype for Base.
 116   template <class T, class Base = default_archetype_base>
 117   class convertible_to_archetype : public Base {
 118   private:
 119     convertible_to_archetype() { }
 120     convertible_to_archetype(const convertible_to_archetype& ) { }
 121     convertible_to_archetype& operator=(const convertible_to_archetype&)
 122       { return *this; }
 123   public:
 124     convertible_to_archetype(detail::dummy_constructor x) : Base(x) { }
 125     operator const T&() const { return static_object<T>::get(); }
 126   };
 127
 128   template <class T, class Base = default_archetype_base>
 129   class convertible_from_archetype : public Base {
 130   private:
 131     convertible_from_archetype() { }
 132     convertible_from_archetype(const convertible_from_archetype& ) { }
 133     convertible_from_archetype& operator=(const convertible_from_archetype&)
 134       { return *this; }
 135   public:
 136     convertible_from_archetype(detail::dummy_constructor x) : Base(x) { }
 137     convertible_from_archetype(const T&) { }
 138     convertible_from_archetype& operator=(const T&)
 139       { return *this; }
 140   };
 141
 142   class boolean_archetype {
 143   public:
 144     boolean_archetype(const boolean_archetype&) { }
 145     operator bool() const { return true; }
 146     boolean_archetype(detail::dummy_constructor) { }
 147   private:
 148     boolean_archetype() { }
 149     boolean_archetype& operator=(const boolean_archetype&) { return *this; }
 150   };
 151
 152   template <class Base = null_archetype<> >
 153   class equality_comparable_archetype : public Base {
 154   public:
 155     equality_comparable_archetype(detail::dummy_constructor x) : Base(x) { }
 156   };
 157   template <class Base>
 158   boolean_archetype
 159   operator==(const equality_comparable_archetype<Base>&,
 160              const equality_comparable_archetype<Base>&)
 161   {
 162     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 163   }
 164   template <class Base>
 165   boolean_archetype
 166   operator!=(const equality_comparable_archetype<Base>&,
 167              const equality_comparable_archetype<Base>&)
 168   {
 169     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 170   }
 171
 172
 173   template <class Base = null_archetype<> >
 174   class equality_comparable2_first_archetype : public Base {
 175   public:
 176     equality_comparable2_first_archetype(detail::dummy_constructor x)
 177       : Base(x) { }
 178   };
 179   template <class Base = null_archetype<> >
 180   class equality_comparable2_second_archetype : public Base {
 181   public:
 182     equality_comparable2_second_archetype(detail::dummy_constructor x)
 183       : Base(x) { }
 184   };
 185   template <class Base1, class Base2>
 186   boolean_archetype
 187   operator==(const equality_comparable2_first_archetype<Base1>&,
 188              const equality_comparable2_second_archetype<Base2>&)
 189   {
 190     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 191   }
 192   template <class Base1, class Base2>
 193   boolean_archetype
 194   operator!=(const equality_comparable2_first_archetype<Base1>&,
 195              const equality_comparable2_second_archetype<Base2>&)
 196   {
 197     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 198   }
 199
 200
 201   template <class Base = null_archetype<> >
 202   class less_than_comparable_archetype : public Base {
 203   public:
 204     less_than_comparable_archetype(detail::dummy_constructor x) : Base(x) { }
 205   };
 206   template <class Base>
 207   boolean_archetype
 208   operator<(const less_than_comparable_archetype<Base>&,
 209             const less_than_comparable_archetype<Base>&)
 210   {
 211     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 212   }
 213
 214
 215
 216   template <class Base = null_archetype<> >
 217   class comparable_archetype : public Base {
 218   public:
 219     comparable_archetype(detail::dummy_constructor x) : Base(x) { }
 220   };
 221   template <class Base>
 222   boolean_archetype
 223   operator<(const comparable_archetype<Base>&,
 224             const comparable_archetype<Base>&)
 225   {
 226     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 227   }
 228   template <class Base>
 229   boolean_archetype
 230   operator<=(const comparable_archetype<Base>&,
 231              const comparable_archetype<Base>&)
 232   {
 233     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 234   }
 235   template <class Base>
 236   boolean_archetype
 237   operator>(const comparable_archetype<Base>&,
 238             const comparable_archetype<Base>&)
 239   {
 240     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 241   }
 242   template <class Base>
 243   boolean_archetype
 244   operator>=(const comparable_archetype<Base>&,
 245              const comparable_archetype<Base>&)
 246   {
 247     return boolean_archetype(static_object<detail::dummy_constructor>::get());
 248   }
 249
 250
 251   // The purpose of the optags is so that one can specify
 252   // exactly which types the operator< is defined between.
 253   // This is useful for allowing the operations:
 254   //
 255   // A a; B b;
 256   // a < b
 257   // b < a
 258   //
 259   // without also allowing the combinations:
 260   //
 261   // a < a
 262   // b < b
 263   //
 264   struct optag1 { };
 265   struct optag2 { };
 266   struct optag3 { };
 267
 268 #define BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(OP, NAME)                       \
 269   template <class Base = null_archetype<>, class Tag = optag1 >                 \
 270   class NAME##_first_archetype : public Base {                                  \
 271   public:                                                                       \
 272     NAME##_first_archetype(detail::dummy_constructor x) : Base(x) { }           \
 273   };                                                                            \
 274                                                                                 \
 275   template <class Base = null_archetype<>, class Tag = optag1 >                 \
 276   class NAME##_second_archetype : public Base {                                 \
 277   public:                                                                       \
 278     NAME##_second_archetype(detail::dummy_constructor x) : Base(x) { }          \
 279   };                                                                            \
 280                                                                                 \
 281   template <class BaseFirst, class BaseSecond, class Tag>                       \
 282   boolean_archetype                                                             \
 283   operator OP (const NAME##_first_archetype<BaseFirst, Tag>&,                   \
 284                const NAME##_second_archetype<BaseSecond, Tag>&)                 \
 285   {                                                                             \
 286    return boolean_archetype(static_object<detail::dummy_constructor>::get());   \
 287   }
 288
 289   BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(==, equal_op)
 290   BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(!=, not_equal_op)
 291   BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(<, less_than_op)
 292   BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(<=, less_equal_op)
 293   BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(>, greater_than_op)
 294   BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(>=, greater_equal_op)
 295
 296 #define BOOST_DEFINE_OPERATOR_ARCHETYPE(OP, NAME) \
 297   template <class Base = null_archetype<> > \
 298   class NAME##_archetype : public Base { \
 299   public: \
 300     NAME##_archetype(detail::dummy_constructor x) : Base(x) { } \
 301     NAME##_archetype(const NAME##_archetype&)  \
 302       : Base(static_object<detail::dummy_constructor>::get()) { } \
 303     NAME##_archetype& operator=(const NAME##_archetype&) { return *this; } \
 304   }; \
 305   template <class Base> \
 306   NAME##_archetype<Base> \
 307   operator OP (const NAME##_archetype<Base>&,\
 308                const NAME##_archetype<Base>&)  \
 309   { \
 310     return \
 311      NAME##_archetype<Base>(static_object<detail::dummy_constructor>::get()); \
 312   }
 313
 314   BOOST_DEFINE_OPERATOR_ARCHETYPE(+, addable)
 315   BOOST_DEFINE_OPERATOR_ARCHETYPE(-, subtractable)
 316   BOOST_DEFINE_OPERATOR_ARCHETYPE(*, multipliable)
 317   BOOST_DEFINE_OPERATOR_ARCHETYPE(/, dividable)
 318   BOOST_DEFINE_OPERATOR_ARCHETYPE(%, modable)
 319
 320   // As is, these are useless because of the return type.
 321   // Need to invent a better way...
 322 #define BOOST_DEFINE_BINARY_OPERATOR_ARCHETYPE(OP, NAME) \
 323   template <class Return, class Base = null_archetype<> > \
 324   class NAME##_first_archetype : public Base { \
 325   public: \
 326     NAME##_first_archetype(detail::dummy_constructor x) : Base(x) { } \
 327   }; \
 328   \
 329   template <class Return, class Base = null_archetype<> > \
 330   class NAME##_second_archetype : public Base { \
 331   public: \
 332     NAME##_second_archetype(detail::dummy_constructor x) : Base(x) { } \
 333   }; \
 334   \
 335   template <class Return, class BaseFirst, class BaseSecond> \
 336   Return \
 337   operator OP (const NAME##_first_archetype<Return, BaseFirst>&, \
 338                const NAME##_second_archetype<Return, BaseSecond>&) \
 339   { \
 340     return Return(static_object<detail::dummy_constructor>::get()); \
 341   }
 342
 343   BOOST_DEFINE_BINARY_OPERATOR_ARCHETYPE(+, plus_op)
 344   BOOST_DEFINE_BINARY_OPERATOR_ARCHETYPE(*, time_op)
 345   BOOST_DEFINE_BINARY_OPERATOR_ARCHETYPE(/, divide_op)
 346   BOOST_DEFINE_BINARY_OPERATOR_ARCHETYPE(-, subtract_op)
 347   BOOST_DEFINE_BINARY_OPERATOR_ARCHETYPE(%, mod_op)
 348
 349   //===========================================================================
 350   // Function Object Archetype Classes
 351
 352   template <class Return>
 353   class generator_archetype {
 354   public:
 355     const Return& operator()() {
 356       return static_object<Return>::get();
 357     }
 358   };
 359
 360   class void_generator_archetype {
 361   public:
 362     void operator()() { }
 363   };
 364
 365   template <class Arg, class Return>
 366   class unary_function_archetype {
 367   private:
 368     unary_function_archetype() { }
 369   public:
 370     unary_function_archetype(detail::dummy_constructor) { }
 371     const Return& operator()(const Arg&) const {
 372       return static_object<Return>::get();
 373     }
 374   };
 375
 376   template <class Arg1, class Arg2, class Return>
 377   class binary_function_archetype {
 378   private:
 379     binary_function_archetype() { }
 380   public:
 381     binary_function_archetype(detail::dummy_constructor) { }
 382     const Return& operator()(const Arg1&, const Arg2&) const {
 383       return static_object<Return>::get();
 384     }
 385   };
 386
 387   template <class Arg>
 388   class unary_predicate_archetype {
 389     typedef boolean_archetype Return;
 390     unary_predicate_archetype() { }
 391   public:
 392     unary_predicate_archetype(detail::dummy_constructor) { }
 393     const Return& operator()(const Arg&) const {
 394       return static_object<Return>::get();
 395     }
 396   };
 397
 398   template <class Arg1, class Arg2, class Base = null_archetype<> >
 399   class binary_predicate_archetype {
 400     typedef boolean_archetype Return;
 401     binary_predicate_archetype() { }
 402   public:
 403     binary_predicate_archetype(detail::dummy_constructor) { }
 404     const Return& operator()(const Arg1&, const Arg2&) const {
 405       return static_object<Return>::get();
 406     }
 407   };
 408
 409   //===========================================================================
 410   // Iterator Archetype Classes
 411
 412   template <class T, int I = 0>
 413   class input_iterator_archetype
 414   {
 415   private:
 416     typedef input_iterator_archetype self;
 417   public:
 418     typedef std::input_iterator_tag iterator_category;
 419     typedef T value_type;
 420     struct reference {
 421       operator const value_type&() const { return static_object<T>::get(); }
 422     };
 423     typedef const T* pointer;
 424     typedef std::ptrdiff_t difference_type;
 425     self& operator=(const self&) { return *this;  }
 426     bool operator==(const self&) const { return true; }
 427     bool operator!=(const self&) const { return true; }
 428     reference operator*() const { return reference(); }
 429     self& operator++() { return *this; }
 430     self operator++(int) { return *this; }
 431   };
 432
 433   template <class T>
 434   class input_iterator_archetype_no_proxy
 435   {
 436   private:
 437     typedef input_iterator_archetype_no_proxy self;
 438   public:
 439     typedef std::input_iterator_tag iterator_category;
 440     typedef T value_type;
 441     typedef const T& reference;
 442     typedef const T* pointer;
 443     typedef std::ptrdiff_t difference_type;
 444     self& operator=(const self&) { return *this;  }
 445     bool operator==(const self&) const { return true; }
 446     bool operator!=(const self&) const { return true; }
 447     reference operator*() const { return static_object<T>::get(); }
 448     self& operator++() { return *this; }
 449     self operator++(int) { return *this; }
 450   };
 451
 452   template <class T>
 453   struct output_proxy {
 454     output_proxy& operator=(const T&) { return *this; }
 455   };
 456
 457   template <class T>
 458   class output_iterator_archetype
 459   {
 460   public:
 461     typedef output_iterator_archetype self;
 462   public:
 463     typedef std::output_iterator_tag iterator_category;
 464     typedef output_proxy<T> value_type;
 465     typedef output_proxy<T> reference;
 466     typedef void pointer;
 467     typedef void difference_type;
 468     output_iterator_archetype(detail::dummy_constructor) { }
 469     output_iterator_archetype(const self&) { }
 470     self& operator=(const self&) { return *this; }
 471     bool operator==(const self&) const { return true; }
 472     bool operator!=(const self&) const { return true; }
 473     reference operator*() const { return output_proxy<T>(); }
 474     self& operator++() { return *this; }
 475     self operator++(int) { return *this; }
 476   private:
 477     output_iterator_archetype() { }
 478   };
 479
 480   template <class T>
 481   class input_output_iterator_archetype
 482   {
 483   private:
 484     typedef input_output_iterator_archetype self;
 485     struct in_out_tag : public std::input_iterator_tag, public std::output_iterator_tag { };
 486   public:
 487     typedef in_out_tag iterator_category;
 488     typedef T value_type;
 489     struct reference {
 490       reference& operator=(const T&) { return *this; }
 491       operator value_type() { return static_object<T>::get(); }
 492     };
 493     typedef const T* pointer;
 494     typedef std::ptrdiff_t difference_type;
 495     input_output_iterator_archetype() { }
 496     self& operator=(const self&) { return *this;  }
 497     bool operator==(const self&) const { return true; }
 498     bool operator!=(const self&) const { return true; }
 499     reference operator*() const { return reference(); }
 500     self& operator++() { return *this; }
 501     self operator++(int) { return *this; }
 502   };
 503
 504   template <class T>
 505   class forward_iterator_archetype
 506   {
 507   public:
 508     typedef forward_iterator_archetype self;
 509   public:
 510     typedef std::forward_iterator_tag iterator_category;
 511     typedef T value_type;
 512     typedef const T& reference;
 513     typedef T const* pointer;
 514     typedef std::ptrdiff_t difference_type;
 515     forward_iterator_archetype() { }
 516     self& operator=(const self&) { return *this;  }
 517     bool operator==(const self&) const { return true; }
 518     bool operator!=(const self&) const { return true; }
 519     reference operator*() const { return static_object<T>::get(); }
 520     self& operator++() { return *this; }
 521     self operator++(int) { return *this; }
 522   };
 523
 524   template <class T>
 525   class mutable_forward_iterator_archetype
 526   {
 527   public:
 528     typedef mutable_forward_iterator_archetype self;
 529   public:
 530     typedef std::forward_iterator_tag iterator_category;
 531     typedef T value_type;
 532     typedef T& reference;
 533     typedef T* pointer;
 534     typedef std::ptrdiff_t difference_type;
 535     mutable_forward_iterator_archetype() { }
 536     self& operator=(const self&) { return *this;  }
 537     bool operator==(const self&) const { return true; }
 538     bool operator!=(const self&) const { return true; }
 539     reference operator*() const { return static_object<T>::get(); }
 540     self& operator++() { return *this; }
 541     self operator++(int) { return *this; }
 542   };
 543
 544   template <class T>
 545   class bidirectional_iterator_archetype
 546   {
 547   public:
 548     typedef bidirectional_iterator_archetype self;
 549   public:
 550     typedef std::bidirectional_iterator_tag iterator_category;
 551     typedef T value_type;
 552     typedef const T& reference;
 553     typedef T* pointer;
 554     typedef std::ptrdiff_t difference_type;
 555     bidirectional_iterator_archetype() { }
 556     self& operator=(const self&) { return *this;  }
 557     bool operator==(const self&) const { return true; }
 558     bool operator!=(const self&) const { return true; }
 559     reference operator*() const { return static_object<T>::get(); }
 560     self& operator++() { return *this; }
 561     self operator++(int) { return *this; }
 562     self& operator--() { return *this; }
 563     self operator--(int) { return *this; }
 564   };
 565
 566   template <class T>
 567   class mutable_bidirectional_iterator_archetype
 568   {
 569   public:
 570     typedef mutable_bidirectional_iterator_archetype self;
 571   public:
 572     typedef std::bidirectional_iterator_tag iterator_category;
 573     typedef T value_type;
 574     typedef T& reference;
 575     typedef T* pointer;
 576     typedef std::ptrdiff_t difference_type;
 577     mutable_bidirectional_iterator_archetype() { }
 578     self& operator=(const self&) { return *this;  }
 579     bool operator==(const self&) const { return true; }
 580     bool operator!=(const self&) const { return true; }
 581     reference operator*() const { return static_object<T>::get(); }
 582     self& operator++() { return *this; }
 583     self operator++(int) { return *this; }
 584     self& operator--() { return *this; }
 585     self operator--(int) { return *this; }
 586   };
 587
 588   template <class T>
 589   class random_access_iterator_archetype
 590   {
 591   public:
 592     typedef random_access_iterator_archetype self;
 593   public:
 594     typedef std::random_access_iterator_tag iterator_category;
 595     typedef T value_type;
 596     typedef const T& reference;
 597     typedef T* pointer;
 598     typedef std::ptrdiff_t difference_type;
 599     random_access_iterator_archetype() { }
 600     self& operator=(const self&) { return *this;  }
 601     bool operator==(const self&) const { return true; }
 602     bool operator!=(const self&) const { return true; }
 603     reference operator*() const { return static_object<T>::get(); }
 604     self& operator++() { return *this; }
 605     self operator++(int) { return *this; }
 606     self& operator--() { return *this; }
 607     self operator--(int) { return *this; }
 608     reference operator[](difference_type) const
 609       { return static_object<T>::get(); }
 610     self& operator+=(difference_type) { return *this; }
 611     self& operator-=(difference_type) { return *this; }
 612     difference_type operator-(const self&) const
 613       { return difference_type(); }
 614     self operator+(difference_type) const { return *this; }
 615     self operator-(difference_type) const { return *this; }
 616     bool operator<(const self&) const { return true; }
 617     bool operator<=(const self&) const { return true; }
 618     bool operator>(const self&) const { return true; }
 619     bool operator>=(const self&) const { return true; }
 620   };
 621   template <class T>
 622   random_access_iterator_archetype<T>
 623   operator+(typename random_access_iterator_archetype<T>::difference_type,
 624             const random_access_iterator_archetype<T>& x)
 625     { return x; }
 626
 627
 628   template <class T>
 629   class mutable_random_access_iterator_archetype
 630   {
 631   public:
 632     typedef mutable_random_access_iterator_archetype self;
 633   public:
 634     typedef std::random_access_iterator_tag iterator_category;
 635     typedef T value_type;
 636     typedef T& reference;
 637     typedef T* pointer;
 638     typedef std::ptrdiff_t difference_type;
 639     mutable_random_access_iterator_archetype() { }
 640     self& operator=(const self&) { return *this;  }
 641     bool operator==(const self&) const { return true; }
 642     bool operator!=(const self&) const { return true; }
 643     reference operator*() const { return static_object<T>::get(); }
 644     self& operator++() { return *this; }
 645     self operator++(int) { return *this; }
 646     self& operator--() { return *this; }
 647     self operator--(int) { return *this; }
 648     reference operator[](difference_type) const
 649       { return static_object<T>::get(); }
 650     self& operator+=(difference_type) { return *this; }
 651     self& operator-=(difference_type) { return *this; }
 652     difference_type operator-(const self&) const
 653       { return difference_type(); }
 654     self operator+(difference_type) const { return *this; }
 655     self operator-(difference_type) const { return *this; }
 656     bool operator<(const self&) const { return true; }
 657     bool operator<=(const self&) const { return true; }
 658     bool operator>(const self&) const { return true; }
 659     bool operator>=(const self&) const { return true; }
 660   };
 661   template <class T>
 662   mutable_random_access_iterator_archetype<T>
 663   operator+
 664     (typename mutable_random_access_iterator_archetype<T>::difference_type,
 665      const mutable_random_access_iterator_archetype<T>& x)
 666     { return x; }
 667
 668 } // namespace boost
 669
 670 #endif // BOOST_CONCEPT_ARCHETYPES_H