99 lines
2.6 KiB
C++
99 lines
2.6 KiB
C++
/*=============================================================================
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Copyright (c) 2016 Paul Fultz II
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unpack_tuple.hpp
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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==============================================================================*/
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#ifndef BOOST_HOF_GUARD_UNPACK_TUPLE_HPP
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#define BOOST_HOF_GUARD_UNPACK_TUPLE_HPP
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#include <boost/hof/unpack_sequence.hpp>
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#include <boost/hof/returns.hpp>
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#include <boost/hof/detail/forward.hpp>
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#include <boost/hof/detail/seq.hpp>
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#include <tuple>
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#include <array>
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namespace boost { namespace hof {
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namespace detail {
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template<class Sequence>
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constexpr typename gens<std::tuple_size<Sequence>::value>::type
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make_tuple_gens(const Sequence&)
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{
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return {};
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}
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#if (defined(__GNUC__) && !defined (__clang__) && __GNUC__ == 4 && __GNUC_MINOR__ < 7)
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template<std::size_t I, class Tuple>
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struct tuple_element_return
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: std::tuple_element<I, Tuple>
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{};
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template<std::size_t I, class Tuple>
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struct tuple_element_return<I, Tuple&>
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: std::add_lvalue_reference<typename tuple_element_return<I, Tuple>::type>
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{};
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template<std::size_t I, class Tuple>
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struct tuple_element_return<I, Tuple&&>
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: std::add_rvalue_reference<typename tuple_element_return<I, Tuple>::type>
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{};
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template<std::size_t I, class Tuple>
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struct tuple_element_return<I, const Tuple>
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: std::add_const<typename tuple_element_return<I, Tuple>::type>
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{};
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template< std::size_t I, class Tuple, class R = typename tuple_element_return<I, Tuple&&>::type >
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R tuple_get( Tuple&& t )
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{
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return (R&&)(std::get<I>(boost::hof::forward<Tuple>(t)));
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}
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#define BOOST_HOF_UNPACK_TUPLE_GET boost::hof::detail::tuple_get
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#else
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#define BOOST_HOF_UNPACK_TUPLE_GET std::get
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#endif
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template<class F, class T, std::size_t ...N>
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constexpr auto unpack_tuple(F&& f, T&& t, seq<N...>) BOOST_HOF_RETURNS
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(
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f(
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BOOST_HOF_AUTO_FORWARD(BOOST_HOF_UNPACK_TUPLE_GET<N>(BOOST_HOF_AUTO_FORWARD(t)))...
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)
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);
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struct unpack_tuple_apply
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{
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template<class F, class S>
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constexpr static auto apply(F&& f, S&& t) BOOST_HOF_RETURNS
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(
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boost::hof::detail::unpack_tuple(BOOST_HOF_FORWARD(F)(f), BOOST_HOF_FORWARD(S)(t), boost::hof::detail::make_tuple_gens(t))
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);
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};
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}
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template<class... Ts>
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struct unpack_sequence<std::tuple<Ts...>>
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: detail::unpack_tuple_apply
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{};
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template<class T, class U>
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struct unpack_sequence<std::pair<T, U>>
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: detail::unpack_tuple_apply
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{};
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template<class T, std::size_t N>
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struct unpack_sequence<std::array<T, N>>
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: detail::unpack_tuple_apply
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{};
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}} // namespace boost::hof
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#endif
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