50 lines
1.4 KiB
C++
50 lines
1.4 KiB
C++
/*=============================================================================
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Copyright (c) 2005-2008 Hartmut Kaiser
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Copyright (c) 2005-2007 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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#ifndef PHOENIX_SEQUENCE_AT_HPP
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#define PHOENIX_SEQUENCE_AT_HPP
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#include <boost/fusion/include/at.hpp>
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#include <boost/spirit/home/phoenix/core/actor.hpp>
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#include <boost/spirit/home/phoenix/core/compose.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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namespace boost { namespace phoenix
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{
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template <int N>
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struct at_eval
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{
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template <typename Env, typename Tuple>
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struct result
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{
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typedef typename Tuple::template result<Env>::type tuple;
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typedef typename
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fusion::result_of::at_c<
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typename remove_reference<tuple>::type, N
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>::type
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type;
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};
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template <typename RT, typename Env, typename Tuple>
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static RT
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eval(Env const& env, Tuple const& t)
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{
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return fusion::at_c<N>(t.eval(env));
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}
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};
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template <int N, typename Tuple>
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inline actor<typename as_composite<at_eval<N>, Tuple>::type>
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at_c(Tuple const& tup)
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{
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return compose<at_eval<N> >(tup);
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}
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}}
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#endif
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