boost/boost/mpl/has_xxx.hpp

   1
   2 #ifndef BOOST_MPL_HAS_XXX_HPP_INCLUDED
   3 #define BOOST_MPL_HAS_XXX_HPP_INCLUDED
   4
   5 // Copyright Aleksey Gurtovoy 2002-2006
   6 // Copyright David Abrahams 2002-2003
   7 // Copyright Daniel Walker 2007
   8 //
   9 // Distributed under the Boost Software License, Version 1.0.
  10 // (See accompanying file LICENSE_1_0.txt or copy at
  11 // http://www.boost.org/LICENSE_1_0.txt)
  12 //
  13 // See http://www.boost.org/libs/mpl for documentation.
  14
  15 // $Id$
  16 // $Date$
  17 // $Revision$
  18
  19 #include <boost/mpl/bool.hpp>
  20 #include <boost/mpl/aux_/na_spec.hpp>
  21 #include <boost/mpl/aux_/type_wrapper.hpp>
  22 #include <boost/mpl/aux_/yes_no.hpp>
  23 #include <boost/mpl/aux_/config/gcc.hpp>
  24 #include <boost/mpl/aux_/config/has_xxx.hpp>
  25 #include <boost/mpl/aux_/config/msvc_typename.hpp>
  26 #include <boost/mpl/aux_/config/msvc.hpp>
  27 #include <boost/mpl/aux_/config/static_constant.hpp>
  28 #include <boost/mpl/aux_/config/workaround.hpp>
  29
  30 #include <boost/preprocessor/array/elem.hpp>
  31 #include <boost/preprocessor/cat.hpp>
  32 #include <boost/preprocessor/control/if.hpp>
  33 #include <boost/preprocessor/repetition/enum_params.hpp>
  34 #include <boost/preprocessor/repetition/enum_trailing_params.hpp>
  35
  36 #if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x590) )
  37 # include <boost/type_traits/is_class.hpp>
  38 #endif
  39
  40 #if !defined(BOOST_MPL_CFG_NO_HAS_XXX)
  41
  42 #   if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
  43
  44 // agurt, 11/sep/02: MSVC-specific version (< 7.1), based on a USENET
  45 // newsgroup's posting by John Madsen (comp.lang.c++.moderated,
  46 // 1999-11-12 19:17:06 GMT); the code is _not_ standard-conforming, but
  47 // it works way more reliably than the SFINAE-based implementation
  48
  49 // Modified dwa 8/Oct/02 to handle reference types.
  50
  51 #   include <boost/mpl/if.hpp>
  52 #   include <boost/mpl/bool.hpp>
  53
  54 namespace boost { namespace mpl { namespace aux {
  55
  56 struct has_xxx_tag;
  57
  58 #if BOOST_WORKAROUND(BOOST_MSVC, == 1300)
  59 template< typename U > struct msvc_incomplete_array
  60 {
  61     typedef char (&type)[sizeof(U) + 1];
  62 };
  63 #endif
  64
  65 template< typename T >
  66 struct msvc_is_incomplete
  67 {
  68     // MSVC is capable of some kinds of SFINAE.  If U is an incomplete
  69     // type, it won't pick the second overload
  70     static char tester(...);
  71
  72 #if BOOST_WORKAROUND(BOOST_MSVC, == 1300)
  73     template< typename U >
  74     static typename msvc_incomplete_array<U>::type tester(type_wrapper<U>);
  75 #else
  76     template< typename U >
  77     static char (& tester(type_wrapper<U>) )[sizeof(U)+1];
  78 #endif
  79
  80     BOOST_STATIC_CONSTANT(bool, value =
  81           sizeof(tester(type_wrapper<T>())) == 1
  82         );
  83 };
  84
  85 template<>
  86 struct msvc_is_incomplete<int>
  87 {
  88     BOOST_STATIC_CONSTANT(bool, value = false);
  89 };
  90
  91 }}}
  92
  93 #   define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, default_) \
  94 template< typename T, typename name = ::boost::mpl::aux::has_xxx_tag > \
  95 struct BOOST_PP_CAT(trait,_impl) : T \
  96 { \
  97     static boost::mpl::aux::no_tag \
  98     test(void(*)(::boost::mpl::aux::has_xxx_tag)); \
  99     \
 100     static boost::mpl::aux::yes_tag test(...); \
 101     \
 102     BOOST_STATIC_CONSTANT(bool, value = \
 103           sizeof(test(static_cast<void(*)(name)>(0))) \
 104             != sizeof(boost::mpl::aux::no_tag) \
 105         ); \
 106     typedef boost::mpl::bool_<value> type; \
 107 }; \
 108 \
 109 template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
 110 struct trait \
 111     : boost::mpl::if_c< \
 112           boost::mpl::aux::msvc_is_incomplete<T>::value \
 113         , boost::mpl::bool_<false> \
 114         , BOOST_PP_CAT(trait,_impl)<T> \
 115         >::type \
 116 { \
 117 }; \
 118 \
 119 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, void) \
 120 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, bool) \
 121 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, char) \
 122 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed char) \
 123 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned char) \
 124 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed short) \
 125 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned short) \
 126 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed int) \
 127 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned int) \
 128 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed long) \
 129 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned long) \
 130 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, float) \
 131 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, double) \
 132 BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, long double) \
 133 /**/
 134
 135 #   define BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, T) \
 136 template<> struct trait<T> \
 137 { \
 138     BOOST_STATIC_CONSTANT(bool, value = false); \
 139     typedef boost::mpl::bool_<false> type; \
 140 }; \
 141 /**/
 142
 143 #if !defined(BOOST_NO_INTRINSIC_WCHAR_T)
 144 #   define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, unused) \
 145     BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, unused) \
 146     BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, wchar_t) \
 147 /**/
 148 #else
 149 #   define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, unused) \
 150     BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, unused) \
 151 /**/
 152 #endif
 153
 154
 155 // SFINAE-based implementations below are derived from a USENET newsgroup's
 156 // posting by Rani Sharoni (comp.lang.c++.moderated, 2002-03-17 07:45:09 PST)
 157
 158 #   elif BOOST_WORKAROUND(BOOST_MSVC, <= 1400) \
 159       || (BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1800)) && defined(__CUDACC__)) \
 160       || BOOST_WORKAROUND(__IBMCPP__, <= 700)
 161
 162 // MSVC 7.1 & MSVC 8.0 & VACPP
 163
 164 // agurt, 15/jun/05: replace overload-based SFINAE implementation with SFINAE
 165 // applied to partial specialization to fix some apparently random failures
 166 // (thanks to Daniel Wallin for researching this!)
 167
 168 #   define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \
 169 template< typename T > \
 170 struct BOOST_PP_CAT(trait, _msvc_sfinae_helper) \
 171 { \
 172     typedef void type; \
 173 };\
 174 \
 175 template< typename T, typename U = void > \
 176 struct BOOST_PP_CAT(trait,_impl_) \
 177 { \
 178     BOOST_STATIC_CONSTANT(bool, value = false); \
 179     typedef boost::mpl::bool_<value> type; \
 180 }; \
 181 \
 182 template< typename T > \
 183 struct BOOST_PP_CAT(trait,_impl_)< \
 184       T \
 185     , typename BOOST_PP_CAT(trait, _msvc_sfinae_helper)< typename T::name >::type \
 186     > \
 187 { \
 188     BOOST_STATIC_CONSTANT(bool, value = true); \
 189     typedef boost::mpl::bool_<value> type; \
 190 }; \
 191 \
 192 template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
 193 struct trait \
 194     : BOOST_PP_CAT(trait,_impl_)<T> \
 195 { \
 196 }; \
 197 /**/
 198
 199 #   elif BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x590) )
 200
 201 #   define BOOST_MPL_HAS_XXX_TRAIT_NAMED_BCB_DEF(trait, trait_tester, name, default_) \
 202 template< typename T, bool IS_CLASS > \
 203 struct trait_tester \
 204 { \
 205     BOOST_STATIC_CONSTANT( bool,  value = false ); \
 206 }; \
 207 template< typename T > \
 208 struct trait_tester< T, true > \
 209 { \
 210     struct trait_tester_impl \
 211     { \
 212         template < class U > \
 213         static int  resolve( boost::mpl::aux::type_wrapper<U> const volatile * \
 214                            , boost::mpl::aux::type_wrapper<typename U::name >* = 0 ); \
 215         static char resolve( ... ); \
 216     }; \
 217     typedef boost::mpl::aux::type_wrapper<T> t_; \
 218     BOOST_STATIC_CONSTANT( bool, value = ( sizeof( trait_tester_impl::resolve( static_cast< t_ * >(0) ) ) == sizeof(int) ) ); \
 219 }; \
 220 template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
 221 struct trait           \
 222 {                      \
 223     BOOST_STATIC_CONSTANT( bool, value = (trait_tester< T, boost::is_class< T >::value >::value) );     \
 224     typedef boost::mpl::bool_< trait< T, fallback_ >::value > type; \
 225 };
 226
 227 #   define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \
 228     BOOST_MPL_HAS_XXX_TRAIT_NAMED_BCB_DEF( trait \
 229                                          , BOOST_PP_CAT(trait,_tester)      \
 230                                          , name       \
 231                                          , default_ ) \
 232 /**/
 233
 234 #   else // other SFINAE-capable compilers
 235
 236 #   define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \
 237 template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
 238 struct trait \
 239 { \
 240     struct gcc_3_2_wknd \
 241     { \
 242         template< typename U > \
 243         static boost::mpl::aux::yes_tag test( \
 244               boost::mpl::aux::type_wrapper<U> const volatile* \
 245             , boost::mpl::aux::type_wrapper<BOOST_MSVC_TYPENAME U::name>* = 0 \
 246             ); \
 247     \
 248         static boost::mpl::aux::no_tag test(...); \
 249     }; \
 250     \
 251     typedef boost::mpl::aux::type_wrapper<T> t_; \
 252     BOOST_STATIC_CONSTANT(bool, value = \
 253           sizeof(gcc_3_2_wknd::test(static_cast<t_*>(0))) \
 254             == sizeof(boost::mpl::aux::yes_tag) \
 255         ); \
 256     typedef boost::mpl::bool_<value> type; \
 257 }; \
 258 /**/
 259
 260 #   endif // BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
 261
 262
 263 #else // BOOST_MPL_CFG_NO_HAS_XXX
 264
 265 // placeholder implementation
 266
 267 #   define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \
 268 template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
 269 struct trait \
 270 { \
 271     BOOST_STATIC_CONSTANT(bool, value = fallback_::value); \
 272     typedef fallback_ type; \
 273 }; \
 274 /**/
 275
 276 #endif
 277
 278 #define BOOST_MPL_HAS_XXX_TRAIT_DEF(name) \
 279     BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(BOOST_PP_CAT(has_,name), name, false) \
 280 /**/
 281
 282
 283 #if !defined(BOOST_MPL_CFG_NO_HAS_XXX_TEMPLATE)
 284
 285 // Create a boolean Metafunction to detect a nested template
 286 // member. This implementation is based on a USENET newsgroup's
 287 // posting by Aleksey Gurtovoy (comp.lang.c++.moderated, 2002-03-19),
 288 // Rani Sharoni's USENET posting cited above, the non-template has_xxx
 289 // implementations above, and discussion on the Boost mailing list.
 290
 291 #   if !defined(BOOST_MPL_HAS_XXX_NO_WRAPPED_TYPES)
 292 #     if BOOST_WORKAROUND(BOOST_MSVC, <= 1400)
 293 #       define BOOST_MPL_HAS_XXX_NO_WRAPPED_TYPES 1
 294 #     else
 295 #       define BOOST_MPL_HAS_XXX_NO_WRAPPED_TYPES 0
 296 #     endif
 297 #   endif
 298
 299 #   if !defined(BOOST_MPL_HAS_XXX_NO_EXPLICIT_TEST_FUNCTION)
 300 #     if (defined(BOOST_NO_EXPLICIT_FUNCTION_TEMPLATE_ARGUMENTS))
 301 #       define BOOST_MPL_HAS_XXX_NO_EXPLICIT_TEST_FUNCTION 1
 302 #     else
 303 #       define BOOST_MPL_HAS_XXX_NO_EXPLICIT_TEST_FUNCTION 0
 304 #     endif
 305 #   endif
 306
 307 #   if !defined(BOOST_MPL_HAS_XXX_NEEDS_TEMPLATE_SFINAE)
 308 #     if BOOST_WORKAROUND(BOOST_MSVC, <= 1400)
 309 #       define BOOST_MPL_HAS_XXX_NEEDS_TEMPLATE_SFINAE 1
 310 #     else
 311 #       define BOOST_MPL_HAS_XXX_NEEDS_TEMPLATE_SFINAE 0
 312 #     endif
 313 #   endif
 314
 315 // NOTE: Many internal implementation macros take a Boost.Preprocessor
 316 // array argument called args which is of the following form.
 317 //           ( 4, ( trait, name, max_arity, default_ ) )
 318
 319 #   define BOOST_MPL_HAS_MEMBER_INTROSPECTION_NAME(args) \
 320       BOOST_PP_CAT(BOOST_PP_ARRAY_ELEM(0, args) , _introspect) \
 321     /**/
 322
 323 #   define BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME(args, n) \
 324       BOOST_PP_CAT(BOOST_PP_CAT(BOOST_PP_ARRAY_ELEM(0, args) , _substitute), n) \
 325     /**/
 326
 327 #   define BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args) \
 328       BOOST_PP_CAT(BOOST_PP_ARRAY_ELEM(0, args) , _test) \
 329     /**/
 330
 331 // Thanks to Guillaume Melquiond for pointing out the need for the
 332 // "substitute" template as an argument to the overloaded test
 333 // functions to get SFINAE to work for member templates with the
 334 // correct name but different number of arguments.
 335 #   define BOOST_MPL_HAS_MEMBER_MULTI_SUBSTITUTE(z, n, args) \
 336       template< \
 337           template< BOOST_PP_ENUM_PARAMS(BOOST_PP_INC(n), typename V) > class V \
 338        > \
 339       struct BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME(args, n) { \
 340       }; \
 341     /**/
 342
 343 #   define BOOST_MPL_HAS_MEMBER_SUBSTITUTE(args, substitute_macro) \
 344       BOOST_PP_REPEAT( \
 345           BOOST_PP_ARRAY_ELEM(2, args) \
 346         , BOOST_MPL_HAS_MEMBER_MULTI_SUBSTITUTE \
 347         , args \
 348       ) \
 349     /**/
 350
 351 #   if !BOOST_MPL_HAS_XXX_NO_EXPLICIT_TEST_FUNCTION
 352 #     define BOOST_MPL_HAS_MEMBER_REJECT(args, member_macro) \
 353         template< typename V > \
 354         static boost::mpl::aux::no_tag \
 355         BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)(...); \
 356       /**/
 357 #   else
 358 #     define BOOST_MPL_HAS_MEMBER_REJECT(args, member_macro) \
 359         static boost::mpl::aux::no_tag \
 360         BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)(...); \
 361       /**/
 362 #   endif
 363
 364 #   if !BOOST_MPL_HAS_XXX_NO_WRAPPED_TYPES
 365 #     define BOOST_MPL_HAS_MEMBER_MULTI_ACCEPT(z, n, args) \
 366         template< typename V > \
 367         static boost::mpl::aux::yes_tag \
 368         BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)( \
 369             boost::mpl::aux::type_wrapper< V > const volatile* \
 370           , BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME(args, n) < \
 371                 V::template BOOST_PP_ARRAY_ELEM(1, args) \
 372             >* = 0 \
 373         ); \
 374       /**/
 375 #     define BOOST_MPL_HAS_MEMBER_ACCEPT(args, member_macro) \
 376         BOOST_PP_REPEAT( \
 377             BOOST_PP_ARRAY_ELEM(2, args) \
 378           , BOOST_MPL_HAS_MEMBER_MULTI_ACCEPT \
 379           , args \
 380         ) \
 381       /**/
 382 #   else
 383 #     define BOOST_MPL_HAS_MEMBER_ACCEPT(args, member_macro) \
 384         template< typename V > \
 385         static boost::mpl::aux::yes_tag \
 386         BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)( \
 387             V const volatile* \
 388           , member_macro(args, V, T)* = 0 \
 389         ); \
 390       /**/
 391 #   endif
 392
 393 #   if !BOOST_MPL_HAS_XXX_NO_EXPLICIT_TEST_FUNCTION
 394 #     define BOOST_MPL_HAS_MEMBER_TEST(args) \
 395           sizeof(BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)< U >(0)) \
 396               == sizeof(boost::mpl::aux::yes_tag) \
 397       /**/
 398 #   else
 399 #     if !BOOST_MPL_HAS_XXX_NO_WRAPPED_TYPES
 400 #       define BOOST_MPL_HAS_MEMBER_TEST(args) \
 401           sizeof( \
 402               BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)( \
 403                   static_cast< boost::mpl::aux::type_wrapper< U >* >(0) \
 404               ) \
 405           ) == sizeof(boost::mpl::aux::yes_tag) \
 406         /**/
 407 #     else
 408 #       define BOOST_MPL_HAS_MEMBER_TEST(args) \
 409           sizeof( \
 410               BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)( \
 411                   static_cast< U* >(0) \
 412               ) \
 413           ) == sizeof(boost::mpl::aux::yes_tag) \
 414         /**/
 415 #     endif
 416 #   endif
 417
 418 #   define BOOST_MPL_HAS_MEMBER_INTROSPECT( \
 419                args, substitute_macro, member_macro \
 420            ) \
 421       template< typename U > \
 422       struct BOOST_MPL_HAS_MEMBER_INTROSPECTION_NAME(args) { \
 423           BOOST_MPL_HAS_MEMBER_SUBSTITUTE(args, substitute_macro) \
 424           BOOST_MPL_HAS_MEMBER_REJECT(args, member_macro) \
 425           BOOST_MPL_HAS_MEMBER_ACCEPT(args, member_macro) \
 426           BOOST_STATIC_CONSTANT( \
 427               bool, value = BOOST_MPL_HAS_MEMBER_TEST(args) \
 428           ); \
 429           typedef boost::mpl::bool_< value > type; \
 430       }; \
 431     /**/
 432
 433 #   define BOOST_MPL_HAS_MEMBER_IMPLEMENTATION( \
 434                args, introspect_macro, substitute_macro, member_macro \
 435            ) \
 436       template< \
 437           typename T \
 438         , typename fallback_ \
 439               = boost::mpl::bool_< BOOST_PP_ARRAY_ELEM(3, args) > \
 440       > \
 441       class BOOST_PP_ARRAY_ELEM(0, args) { \
 442           introspect_macro(args, substitute_macro, member_macro) \
 443       public: \
 444           static const bool value \
 445               = BOOST_MPL_HAS_MEMBER_INTROSPECTION_NAME(args)< T >::value; \
 446           typedef typename BOOST_MPL_HAS_MEMBER_INTROSPECTION_NAME(args)< \
 447               T \
 448           >::type type; \
 449       }; \
 450     /**/
 451
 452 // BOOST_MPL_HAS_MEMBER_WITH_FUNCTION_SFINAE expands to the full
 453 // implementation of the function-based metafunction. Compile with -E
 454 // to see the preprocessor output for this macro.
 455 #   define BOOST_MPL_HAS_MEMBER_WITH_FUNCTION_SFINAE( \
 456                args, substitute_macro, member_macro \
 457            ) \
 458       BOOST_MPL_HAS_MEMBER_IMPLEMENTATION( \
 459           args \
 460         , BOOST_MPL_HAS_MEMBER_INTROSPECT \
 461         , substitute_macro \
 462         , member_macro \
 463       ) \
 464     /**/
 465
 466 #   if BOOST_MPL_HAS_XXX_NEEDS_TEMPLATE_SFINAE
 467
 468 #     if !defined(BOOST_MPL_HAS_XXX_NEEDS_NAMESPACE_LEVEL_SUBSTITUTE)
 469 #       if BOOST_WORKAROUND(BOOST_MSVC, <= 1400)
 470 #         define BOOST_MPL_HAS_XXX_NEEDS_NAMESPACE_LEVEL_SUBSTITUTE 1
 471 #       endif
 472 #     endif
 473
 474 #     if !BOOST_MPL_HAS_XXX_NEEDS_NAMESPACE_LEVEL_SUBSTITUTE
 475 #       define BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME_WITH_TEMPLATE_SFINAE( \
 476                    args, n \
 477                ) \
 478           BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME(args, n) \
 479         /**/
 480 #     else
 481 #       define BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME_WITH_TEMPLATE_SFINAE( \
 482                    args, n \
 483                ) \
 484           BOOST_PP_CAT( \
 485               boost_mpl_has_xxx_ \
 486             , BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME(args, n) \
 487           ) \
 488         /**/
 489 #     endif
 490
 491 #     define BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_TAG_NAME( \
 492                  args \
 493              ) \
 494         BOOST_PP_CAT( \
 495             BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME_WITH_TEMPLATE_SFINAE( \
 496                 args, 0 \
 497             ) \
 498           , _tag \
 499         ) \
 500       /**/
 501
 502 #     define BOOST_MPL_HAS_MEMBER_MULTI_SUBSTITUTE_WITH_TEMPLATE_SFINAE( \
 503                  z, n, args \
 504              ) \
 505         template< \
 506              template< BOOST_PP_ENUM_PARAMS(BOOST_PP_INC(n), typename U) > class U \
 507         > \
 508         struct BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME_WITH_TEMPLATE_SFINAE( \
 509                 args, n \
 510                ) { \
 511             typedef \
 512                 BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_TAG_NAME(args) \
 513                 type; \
 514         }; \
 515       /**/
 516
 517 #     define BOOST_MPL_HAS_MEMBER_SUBSTITUTE_WITH_TEMPLATE_SFINAE( \
 518                  args, substitute_macro \
 519              ) \
 520         typedef void \
 521             BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_TAG_NAME(args); \
 522         BOOST_PP_REPEAT( \
 523             BOOST_PP_ARRAY_ELEM(2, args) \
 524           , BOOST_MPL_HAS_MEMBER_MULTI_SUBSTITUTE_WITH_TEMPLATE_SFINAE \
 525           , args \
 526         ) \
 527       /**/
 528
 529 #     define BOOST_MPL_HAS_MEMBER_REJECT_WITH_TEMPLATE_SFINAE( \
 530                  args, member_macro \
 531              ) \
 532         template< \
 533             typename U \
 534           , typename V \
 535                 = BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_TAG_NAME(args) \
 536         > \
 537         struct BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args) { \
 538             BOOST_STATIC_CONSTANT(bool, value = false); \
 539             typedef boost::mpl::bool_< value > type; \
 540         }; \
 541       /**/
 542
 543 #     define BOOST_MPL_HAS_MEMBER_MULTI_ACCEPT_WITH_TEMPLATE_SFINAE( \
 544                  z, n, args \
 545              ) \
 546         template< typename U > \
 547         struct BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)< \
 548             U \
 549           , typename \
 550                 BOOST_MPL_HAS_MEMBER_INTROSPECTION_SUBSTITUTE_NAME_WITH_TEMPLATE_SFINAE( \
 551                     args, n \
 552                 )< \
 553                     BOOST_MSVC_TYPENAME U::BOOST_PP_ARRAY_ELEM(1, args)< > \
 554                 >::type \
 555         > { \
 556             BOOST_STATIC_CONSTANT(bool, value = true); \
 557             typedef boost::mpl::bool_< value > type; \
 558         }; \
 559       /**/
 560
 561 #     define BOOST_MPL_HAS_MEMBER_ACCEPT_WITH_TEMPLATE_SFINAE( \
 562                  args, member_macro \
 563              ) \
 564         BOOST_PP_REPEAT( \
 565             BOOST_PP_ARRAY_ELEM(2, args) \
 566           , BOOST_MPL_HAS_MEMBER_MULTI_ACCEPT_WITH_TEMPLATE_SFINAE \
 567           , args \
 568         ) \
 569       /**/
 570
 571 #     define BOOST_MPL_HAS_MEMBER_INTROSPECT_WITH_TEMPLATE_SFINAE( \
 572                  args, substitute_macro, member_macro \
 573              ) \
 574         BOOST_MPL_HAS_MEMBER_REJECT_WITH_TEMPLATE_SFINAE(args, member_macro) \
 575         BOOST_MPL_HAS_MEMBER_ACCEPT_WITH_TEMPLATE_SFINAE(args, member_macro) \
 576         template< typename U > \
 577         struct BOOST_MPL_HAS_MEMBER_INTROSPECTION_NAME(args) \
 578             : BOOST_MPL_HAS_MEMBER_INTROSPECTION_TEST_NAME(args)< U > { \
 579         }; \
 580       /**/
 581
 582 // BOOST_MPL_HAS_MEMBER_WITH_TEMPLATE_SFINAE expands to the full
 583 // implementation of the template-based metafunction. Compile with -E
 584 // to see the preprocessor output for this macro.
 585 //
 586 // Note that if BOOST_MPL_HAS_XXX_NEEDS_NAMESPACE_LEVEL_SUBSTITUTE is
 587 // defined BOOST_MPL_HAS_MEMBER_SUBSTITUTE_WITH_TEMPLATE_SFINAE needs
 588 // to be expanded at namespace level before
 589 // BOOST_MPL_HAS_MEMBER_WITH_TEMPLATE_SFINAE can be used.
 590 #     define BOOST_MPL_HAS_MEMBER_WITH_TEMPLATE_SFINAE( \
 591                  args, substitute_macro, member_macro \
 592              ) \
 593         BOOST_MPL_HAS_MEMBER_SUBSTITUTE_WITH_TEMPLATE_SFINAE( \
 594             args, substitute_macro \
 595         ) \
 596         BOOST_MPL_HAS_MEMBER_IMPLEMENTATION( \
 597             args \
 598           , BOOST_MPL_HAS_MEMBER_INTROSPECT_WITH_TEMPLATE_SFINAE \
 599           , substitute_macro \
 600           , member_macro \
 601         ) \
 602       /**/
 603
 604 #   endif // BOOST_MPL_HAS_XXX_NEEDS_TEMPLATE_SFINAE
 605
 606 // Note: In the current implementation the parameter and access macros
 607 // are no longer expanded.
 608 #   if !BOOST_WORKAROUND(BOOST_MSVC, <= 1400)
 609 #     define BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF(trait, name, default_) \
 610         BOOST_MPL_HAS_MEMBER_WITH_FUNCTION_SFINAE( \
 611             ( 4, ( trait, name, BOOST_MPL_LIMIT_METAFUNCTION_ARITY, default_ ) ) \
 612           , BOOST_MPL_HAS_MEMBER_TEMPLATE_SUBSTITUTE_PARAMETER \
 613           , BOOST_MPL_HAS_MEMBER_TEMPLATE_ACCESS \
 614         ) \
 615       /**/
 616 #   else
 617 #     define BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF(trait, name, default_) \
 618         BOOST_MPL_HAS_MEMBER_WITH_TEMPLATE_SFINAE( \
 619             ( 4, ( trait, name, BOOST_MPL_LIMIT_METAFUNCTION_ARITY, default_ ) ) \
 620           , BOOST_MPL_HAS_MEMBER_TEMPLATE_SUBSTITUTE_PARAMETER \
 621           , BOOST_MPL_HAS_MEMBER_TEMPLATE_ACCESS \
 622         ) \
 623       /**/
 624 #   endif
 625
 626 #else // BOOST_MPL_CFG_NO_HAS_XXX_TEMPLATE
 627
 628 // placeholder implementation
 629
 630 #   define BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF(trait, name, default_) \
 631       template< typename T \
 632               , typename fallback_ = boost::mpl::bool_< default_ > > \
 633       struct trait { \
 634           BOOST_STATIC_CONSTANT(bool, value = fallback_::value); \
 635           typedef fallback_ type; \
 636       }; \
 637     /**/
 638
 639 #endif // BOOST_MPL_CFG_NO_HAS_XXX_TEMPLATE
 640
 641 #   define BOOST_MPL_HAS_XXX_TEMPLATE_DEF(name) \
 642       BOOST_MPL_HAS_XXX_TEMPLATE_NAMED_DEF( \
 643           BOOST_PP_CAT(has_, name), name, false \
 644       ) \
 645     /**/
 646
 647 #endif // BOOST_MPL_HAS_XXX_HPP_INCLUDED