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- // Copyright Daniel Wallin 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)
- #include <boost/parameter/config.hpp>
- #if (BOOST_PARAMETER_MAX_ARITY < 2)
- #error Define BOOST_PARAMETER_MAX_ARITY as 2 or greater.
- #endif
- #if !defined(BOOST_PARAMETER_HAS_PERFECT_FORWARDING) && \
- (BOOST_PARAMETER_EXPONENTIAL_OVERLOAD_THRESHOLD_ARITY < 2)
- #error Define BOOST_PARAMETER_EXPONENTIAL_OVERLOAD_THRESHOLD_ARITY \
- as 2 or greater.
- #endif
- #include <boost/parameter/preprocessor.hpp>
- #include <boost/parameter/name.hpp>
- #include <boost/parameter/aux_/preprocessor/nullptr.hpp>
- #include <boost/tuple/tuple.hpp>
- #include <boost/core/enable_if.hpp>
- #include <string>
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- #include <boost/mp11/utility.hpp>
- #include <type_traits>
- #else
- #include <boost/mpl/bool.hpp>
- #include <boost/mpl/if.hpp>
- #include <boost/type_traits/is_convertible.hpp>
- #endif
- namespace test {
- BOOST_PARAMETER_NAME(x)
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- template <typename T, typename Args>
- using predicate = std::is_convertible<T,char const*>;
- BOOST_PARAMETER_FUNCTION((int), sfinae, test::tag,
- (deduced
- (optional
- (x
- , *(boost::mp11::mp_quote<test::predicate>)
- , static_cast<char const*>(BOOST_PARAMETER_AUX_PP_NULLPTR)
- )
- )
- )
- )
- #else // !defined(BOOST_PARAMETER_CAN_USE_MP11)
- struct predicate
- {
- template <typename T, typename Args>
- struct apply
- : boost::mpl::if_<
- boost::is_convertible<T,char const*>
- , boost::mpl::true_
- , boost::mpl::false_
- >
- {
- };
- };
- BOOST_PARAMETER_FUNCTION((int), sfinae, test::tag,
- (deduced
- (optional
- (x
- , *(test::predicate)
- , static_cast<char const*>(BOOST_PARAMETER_AUX_PP_NULLPTR)
- )
- )
- )
- )
- #endif // BOOST_PARAMETER_CAN_USE_MP11
- {
- return 1;
- }
- template <typename A0>
- typename boost::enable_if<
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- std::is_same<int,A0>
- #else
- typename boost::mpl::if_<
- boost::is_same<int,A0>
- , boost::mpl::true_
- , boost::mpl::false_
- >::type
- #endif
- , int
- >::type
- sfinae(A0 const& a0)
- {
- return 0;
- }
- } // namespace test
- #include <boost/core/lightweight_test.hpp>
- int main()
- {
- BOOST_TEST_EQ(1, test::sfinae());
- BOOST_TEST_EQ(1, test::sfinae("foo"));
- BOOST_TEST_EQ(0, test::sfinae(1));
- return boost::report_errors();
- }
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