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( BOOST_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
54namespace boost { namespace mpl { namespace aux {
55
56struct has_xxx_tag;
57
58#if BOOST_WORKAROUND(BOOST_MSVC, == 1300)
59template< typename U > struct msvc_incomplete_array
60{
61 typedef char (&type)[sizeof(U) + 1];
62};
63#endif
64
65template< typename T >
66struct 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
85template<>
86struct 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_) \
94template< typename T, typename name = ::boost::mpl::aux::has_xxx_tag > \
95struct 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\
109template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
110struct 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\
119BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, void) \
120BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, bool) \
121BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, char) \
122BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed char) \
123BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned char) \
124BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed short) \
125BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned short) \
126BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed int) \
127BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned int) \
128BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed long) \
129BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned long) \
130BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, float) \
131BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, double) \
132BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, long double) \
133/**/
134
135# define BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, T) \
136template<> 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_) \
169template< typename T > \
170struct BOOST_PP_CAT(trait, _msvc_sfinae_helper) \
171{ \
172 typedef void type; \
173};\
174\
175template< typename T, typename U = void > \
176struct BOOST_PP_CAT(trait,_impl_) \
177{ \
178 BOOST_STATIC_CONSTANT(bool, value = false); \
179 typedef boost::mpl::bool_<value> type; \
180}; \
181\
182template< typename T > \
183struct 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\
192template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
193struct trait \
194 : BOOST_PP_CAT(trait,_impl_)<T> \
195{ \
196}; \
197/**/
198
199# elif BOOST_WORKAROUND( BOOST_BORLANDC, BOOST_TESTED_AT(0x590) )
200
201# define BOOST_MPL_HAS_XXX_TRAIT_NAMED_BCB_DEF(trait, trait_tester, name, default_) \
202template< typename T, bool IS_CLASS > \
203struct trait_tester \
204{ \
205 BOOST_STATIC_CONSTANT( bool, value = false ); \
206}; \
207template< typename T > \
208struct 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}; \
220template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
221struct 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_) \
237template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
238struct 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_) \
268template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \
269struct 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
648

source code of include/boost/mpl/has_xxx.hpp