46 lines
1.1 KiB
C++
46 lines
1.1 KiB
C++
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#ifndef BOOST_METAPARSE_V1_CPP11_NTH_OF_C_HPP
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#define BOOST_METAPARSE_V1_CPP11_NTH_OF_C_HPP
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// Copyright Abel Sinkovics (abel@sinkovics.hu) 2017.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#include <boost/metaparse/v1/cpp11/impl/nth_of_c.hpp>
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#include <boost/metaparse/v1/fail.hpp>
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#include <boost/metaparse/v1/error/index_out_of_range.hpp>
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#include <type_traits>
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namespace boost
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{
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namespace metaparse
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{
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namespace v1
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{
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template <int N, class... Ps>
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struct nth_of_c
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{
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typedef nth_of_c type;
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template <class S, class Pos>
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struct apply :
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std::conditional<
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(0 <= N && N < sizeof...(Ps)),
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impl::nth_of_c<N, S, Pos, Ps...>,
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typename fail<error::index_out_of_range<0, sizeof...(Ps) - 1, N>>
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::template apply<S, Pos>
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>::type
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{};
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};
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template <int N>
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struct nth_of_c<N> : fail<error::index_out_of_range<0, -1, N>> {};
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}
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}
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}
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#endif
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