ceph/src/boost/libs/tti/include/boost/tti/has_data.hpp

   1
   2 //  (C) Copyright Edward Diener 2012,2013
   3 //  Use, modification and distribution are subject to the Boost Software License,
   4 //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 //  http://www.boost.org/LICENSE_1_0.txt).
   6
   7 #if !defined(BOOST_TTI_HAS_DATA_HPP)
   8 #define BOOST_TTI_HAS_DATA_HPP
   9
  10 #include <boost/config.hpp>
  11 #include <boost/preprocessor/cat.hpp>
  12 #include <boost/type_traits/remove_const.hpp>
  13 #include <boost/tti/gen/has_data_gen.hpp>
  14 #include <boost/tti/detail/ddata.hpp>
  15
  16 /*
  17
  18   The succeeding comments in this file are in doxygen format.
  19
  20 */
  21
  22 /** \file
  23 */
  24
  25 /// Expands to a metafunction which tests whether member data or static member with a particular name and type exists.
  26 /**
  27
  28     trait = the name of the metafunction.
  29
  30     name  = the name of the inner member to introspect.
  31
  32     generates a metafunction called "trait" where 'trait' is the macro parameter.
  33
  34               template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_TYPE>
  35               struct trait
  36                 {
  37                 static const value = unspecified;
  38                 typedef mpl::bool_<true-or-false> type;
  39                 };
  40
  41               The metafunction types and return:
  42
  43                 BOOST_TTI_TP_T    = the enclosing type in which to look for our 'name'
  44
  45                 BOOST_TTI_TP_TYPE = The type of the member data or static member.
  46
  47                 returns  = 'value' is true if the 'name' exists, with the correct data type,
  48                            otherwise 'value' is false.
  49
  50 */
  51 #define BOOST_TTI_TRAIT_HAS_DATA(trait,name) \
  52   BOOST_TTI_DETAIL_TRAIT_HAS_DATA(trait,name) \
  53   template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_TYPE> \
  54   struct trait \
  55     { \
  56     typedef typename \
  57     BOOST_PP_CAT(trait,_detail_hd) \
  58       < \
  59       typename boost::remove_const<BOOST_TTI_TP_T>::type, \
  60       BOOST_TTI_TP_TYPE \
  61       >::type type; \
  62     BOOST_STATIC_CONSTANT(bool,value=type::value); \
  63     }; \
  64 /**/
  65
  66 /// Expands to a metafunction which tests whether member data or static member data with a particular name and type exists.
  67 /**
  68
  69     name  = the name of the inner member.
  70
  71     generates a metafunction called "has_data_name" where 'name' is the macro parameter.
  72
  73               template<class BOOST_TTI_TP_T,class BOOST_TTI_TP_TYPE>
  74               struct has_data_name
  75                 {
  76                 static const value = unspecified;
  77                 typedef mpl::bool_<true-or-false> type;
  78                 };
  79
  80               The metafunction types and return:
  81
  82                 BOOST_TTI_TP_T    = the enclosing type in which to look for our 'name'
  83
  84                 BOOST_TTI_TP_TYPE = The type of the member data or static member.
  85
  86                 returns  = 'value' is true if the 'name' exists, with the correct data type,
  87                            otherwise 'value' is false.
  88
  89 */
  90 #define BOOST_TTI_HAS_DATA(name) \
  91   BOOST_TTI_TRAIT_HAS_DATA \
  92   ( \
  93   BOOST_TTI_HAS_DATA_GEN(name), \
  94   name \
  95   ) \
  96 /**/
  97
  98 #endif // BOOST_TTI_HAS_DATA_HPP