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- // Copyright Cromwell D. Enage 2019.
- // 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_PARAMETER_AUX_HAS_NESTED_TEMPLATE_FN_HPP
- #define BOOST_PARAMETER_AUX_HAS_NESTED_TEMPLATE_FN_HPP
- #include <boost/parameter/aux_/yesno.hpp>
- #include <boost/parameter/aux_/preprocessor/nullptr.hpp>
- #include <boost/parameter/config.hpp>
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- #include <boost/mp11/integral.hpp>
- #include <boost/mp11/utility.hpp>
- #else
- #include <boost/mpl/bool.hpp>
- #include <boost/mpl/identity.hpp>
- #endif
- namespace boost { namespace parameter { namespace aux {
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- template <template <typename ...> class F>
- struct has_nested_template_fn_variadic
- {
- };
- #else
- template <template <typename P0, typename P1> class F>
- struct has_nested_template_fn_arity_2
- {
- };
- #endif
- template <typename T>
- class has_nested_template_fn_impl
- {
- template <typename U>
- static ::boost::parameter::aux::no_tag _check(...);
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- template <typename U>
- static ::boost::parameter::aux::yes_tag
- _check(
- ::boost::mp11::mp_identity<U> const volatile*
- , ::boost::parameter::aux::has_nested_template_fn_variadic<
- U::template fn
- >* = BOOST_PARAMETER_AUX_PP_NULLPTR
- );
- #else
- template <typename U>
- static BOOST_CONSTEXPR ::boost::parameter::aux::yes_tag
- _check(
- ::boost::mpl::identity<U> const volatile*
- , ::boost::parameter::aux::has_nested_template_fn_arity_2<
- U::template fn
- >* = BOOST_PARAMETER_AUX_PP_NULLPTR
- );
- #endif
- public:
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- using type = ::boost::mp11::mp_bool<
- #else
- typedef ::boost::mpl::bool_<
- #endif
- sizeof(
- ::boost::parameter::aux::has_nested_template_fn_impl<T>
- ::template _check<T>(
- static_cast<
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- ::boost::mp11::mp_identity<T> const volatile*
- #else
- ::boost::mpl::identity<T> const volatile*
- #endif
- >(BOOST_PARAMETER_AUX_PP_NULLPTR)
- )
- ) == sizeof(::boost::parameter::aux::yes_tag)
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- >;
- #else
- > type;
- #endif
- };
- }}} // namespace boost::parameter::aux
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- #include <type_traits>
- #else
- #include <boost/type_traits/remove_const.hpp>
- #endif
- namespace boost { namespace parameter { namespace aux {
- template <typename T>
- #if defined(BOOST_PARAMETER_CAN_USE_MP11)
- using has_nested_template_fn = typename ::boost::parameter::aux
- ::has_nested_template_fn_impl<typename ::std::remove_const<T>::type>
- ::type;
- #else
- struct has_nested_template_fn
- : ::boost::parameter::aux::has_nested_template_fn_impl<
- typename ::boost::remove_const<T>::type
- >::type
- {
- };
- #endif
- }}} // namespace boost::parameter::aux
- #endif // include guard
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