37 lines
848 B
C++
37 lines
848 B
C++
#ifndef BOOST_METAPARSE_V1_CPP11_FIRST_OF_HPP
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#define BOOST_METAPARSE_V1_CPP11_FIRST_OF_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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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 <class... Ps>
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struct first_of
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{
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typedef first_of type;
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template <class S, class Pos>
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struct apply : impl::nth_of_c<0, S, Pos, Ps...> {};
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};
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template <>
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struct first_of<> : fail<error::index_out_of_range<0, -1, 0>> {};
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}
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}
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}
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#endif
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