concept_check/include/boost/concept/requires.hpp

94 lines
2.8 KiB
C++

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