boost/concept/requires.hpp

   1 // Copyright David Abrahams 2006. Distributed under the Boost
   2 // Software License, Version 1.0. (See accompanying
   3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   4 #ifndef BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
   5 # define BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
   6
   7 # include <boost/config.hpp>
   8 # include <boost/parameter/aux_/parenthesized_type.hpp>
   9 # include <boost/concept/assert.hpp>
  10 # include <boost/preprocessor/seq/for_each.hpp>
  11
  12 namespace boost {
  13
  14 // Template for use in handwritten assertions
  15 template <class Model, class More>
  16 struct requires_ : More
  17 {
  18 # if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
  19     typedef typename More::type type;
  20 # endif
  21     BOOST_CONCEPT_ASSERT((Model));
  22 };
  23
  24 // Template for use by macros, where models must be wrapped in parens.
  25 // This isn't in namespace detail to keep extra cruft out of resulting
  26 // error messages.
  27 template <class ModelFn>
  28 struct _requires_
  29 {
  30     enum { value = 0 };
  31     BOOST_CONCEPT_ASSERT_FN(ModelFn);
  32 };
  33
  34 template <int check, class Result>
  35 struct Requires_ : ::boost::parameter::aux::unaryfunptr_arg_type<Result>
  36 {
  37 # if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
  38     typedef typename ::boost::parameter::aux::unaryfunptr_arg_type<Result>::type type;
  39 # endif
  40 };
  41
  42 # if BOOST_WORKAROUND(BOOST_INTEL_WIN, BOOST_TESTED_AT(1010))
  43 #  define BOOST_CONCEPT_REQUIRES_(r,data,t) | (::boost::_requires_<void(*)t>::value)
  44 # else
  45 #  define BOOST_CONCEPT_REQUIRES_(r,data,t) + (::boost::_requires_<void(*)t>::value)
  46 # endif
  47
  48 #if defined(NDEBUG) || BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  49
  50 # define BOOST_CONCEPT_REQUIRES(models, result)                                    \
  51     typename ::boost::parameter::aux::unaryfunptr_arg_type<void(*)result>::type
  52
  53 #elif BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
  54
  55 // Same thing as below without the initial typename
  56 # define BOOST_CONCEPT_REQUIRES(models, result)                                \
  57     ::boost::Requires_<                                                        \
  58       (0 BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_REQUIRES_, ~, models)),           \
  59       ::boost::parameter::aux::unaryfunptr_arg_type<void(*)result>          \
  60                      >::type
  61
  62 #else
  63
  64 // This just ICEs on MSVC6 :(
  65 # define BOOST_CONCEPT_REQUIRES(models, result)                                        \
  66     typename ::boost::Requires_<                                                       \
  67       (0 BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_REQUIRES_, ~, models)),                   \
  68       void(*)result                                                                 \
  69     >::type
  70
  71 #endif
  72
  73 // C++0x proposed syntax changed.  This supports an older usage
  74 #define BOOST_CONCEPT_WHERE(models,result) BOOST_CONCEPT_REQUIRES(models,result)
  75
  76 } // namespace boost::concept_check
  77
  78 #endif // BOOST_CONCEPT_REQUIRES_DWA2006430_HPP