Chris@16: // Copyright David Abrahams 2006. Distributed under the Boost
Chris@16: // Software License, Version 1.0. (See accompanying
Chris@16: // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: #ifndef BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
Chris@16: # define BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
Chris@16: 
Chris@16: # include <boost/config.hpp>
Chris@16: # include <boost/concept/assert.hpp>
Chris@16: # include <boost/preprocessor/seq/for_each.hpp>
Chris@16: 
Chris@16: namespace boost { 
Chris@16: 
Chris@101: // unaryfunptr_arg_type from parameter/aux_/parenthesized_type.hpp
Chris@101: 
Chris@101: namespace ccheck_aux {
Chris@101: 
Chris@101: // A metafunction that transforms void(*)(T) -> T
Chris@101: template <class UnaryFunctionPointer>
Chris@101: struct unaryfunptr_arg_type;
Chris@101: 
Chris@101: template <class Arg>
Chris@101: struct unaryfunptr_arg_type<void(*)(Arg)>
Chris@101: {
Chris@101:     typedef Arg type;
Chris@101: };
Chris@101: 
Chris@101: template <>
Chris@101: struct unaryfunptr_arg_type<void(*)(void)>
Chris@101: {
Chris@101:     typedef void type;
Chris@101: };
Chris@101: 
Chris@101: } // namespace ccheck_aux
Chris@101: 
Chris@16: // Template for use in handwritten assertions
Chris@16: template <class Model, class More>
Chris@16: struct requires_ : More
Chris@16: {
Chris@16:     BOOST_CONCEPT_ASSERT((Model));
Chris@16: };
Chris@16: 
Chris@16: // Template for use by macros, where models must be wrapped in parens.
Chris@16: // This isn't in namespace detail to keep extra cruft out of resulting
Chris@16: // error messages.
Chris@16: template <class ModelFn>
Chris@16: struct _requires_
Chris@16: {
Chris@16:     enum { value = 0 };
Chris@16:     BOOST_CONCEPT_ASSERT_FN(ModelFn);
Chris@16: };
Chris@16: 
Chris@16: template <int check, class Result>
Chris@101: struct Requires_ : ::boost::ccheck_aux::unaryfunptr_arg_type<Result>
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: # if BOOST_WORKAROUND(BOOST_INTEL_WIN, BOOST_TESTED_AT(1010))
Chris@16: #  define BOOST_CONCEPT_REQUIRES_(r,data,t) | (::boost::_requires_<void(*)t>::value)
Chris@16: # else 
Chris@16: #  define BOOST_CONCEPT_REQUIRES_(r,data,t) + (::boost::_requires_<void(*)t>::value)
Chris@16: # endif
Chris@16: 
Chris@101: #if defined(NDEBUG)
Chris@16: 
Chris@16: # define BOOST_CONCEPT_REQUIRES(models, result)                                    \
Chris@101:     typename ::boost::ccheck_aux::unaryfunptr_arg_type<void(*)result>::type
Chris@16: 
Chris@16: #elif BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
Chris@16: 
Chris@16: // Same thing as below without the initial typename
Chris@16: # define BOOST_CONCEPT_REQUIRES(models, result)                                \
Chris@16:     ::boost::Requires_<                                                        \
Chris@16:       (0 BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_REQUIRES_, ~, models)),           \
Chris@101:       ::boost::ccheck_aux::unaryfunptr_arg_type<void(*)result>          \
Chris@16:                      >::type
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: // This just ICEs on MSVC6 :(
Chris@16: # define BOOST_CONCEPT_REQUIRES(models, result)                                        \
Chris@16:     typename ::boost::Requires_<                                                       \
Chris@16:       (0 BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_REQUIRES_, ~, models)),                   \
Chris@16:       void(*)result                                                                 \
Chris@16:     >::type
Chris@16: 
Chris@16: #endif 
Chris@16: 
Chris@16: // C++0x proposed syntax changed.  This supports an older usage
Chris@16: #define BOOST_CONCEPT_WHERE(models,result) BOOST_CONCEPT_REQUIRES(models,result)
Chris@16: 
Chris@16: } // namespace boost::concept_check
Chris@16: 
Chris@16: #endif // BOOST_CONCEPT_REQUIRES_DWA2006430_HPP