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44 lines
1.3 KiB
44 lines
1.3 KiB
3 years ago
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/*=============================================================================
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Copyright (c) 2001-2011 Joel de Guzman
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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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#if !defined(FUSION_VALUE_AT_IMPL_07172005_0952)
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#define FUSION_VALUE_AT_IMPL_07172005_0952
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#include <boost/fusion/support/config.hpp>
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#include <boost/fusion/support/detail/access.hpp>
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#include <boost/type_traits/is_const.hpp>
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#include <boost/mpl/eval_if.hpp>
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#include <boost/mpl/bool.hpp>
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namespace boost { namespace fusion
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{
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struct cons_tag;
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namespace extension
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{
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template <typename Tag>
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struct value_at_impl;
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template <>
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struct value_at_impl<cons_tag>
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{
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template <typename Sequence, typename N>
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struct apply
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{
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typedef typename
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mpl::eval_if<
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mpl::bool_<N::value == 0>
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, mpl::identity<typename Sequence::car_type>
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, apply<typename Sequence::cdr_type, mpl::int_<N::value-1> >
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>::type
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type;
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};
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};
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}
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}}
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#endif
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