79 lines
2.2 KiB
Plaintext
79 lines
2.2 KiB
Plaintext
/*=============================================================================
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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_REPLACE_IF_08182005_0946)
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#define FUSION_REPLACE_IF_08182005_0946
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#include <boost/fusion/support/config.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/mpl/if.hpp>
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#include <boost/type_traits/remove_reference.hpp>
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namespace boost { namespace fusion { namespace detail
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{
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template <bool is_convertible>
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struct replacer_if_helper;
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template <>
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struct replacer_if_helper<false>
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{
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template <typename U, typename F, typename T>
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static U&
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call(U& x, F&, T const&)
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{
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return x;
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}
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};
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template <>
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struct replacer_if_helper<true>
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{
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template <typename U, typename F, typename T>
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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static U
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call(U& x, F& f, T const& new_value)
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{
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return f(x) ? new_value : x;
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}
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};
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template <typename F, typename T>
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struct replacer_if
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{
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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replacer_if(F in_f, T const& in_new_value)
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: f(in_f), new_value(in_new_value) {}
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template<typename Params>
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struct result;
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template <typename F1, typename T1, typename U>
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struct result<replacer_if<F1, T1>(U)>
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{
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typedef typename remove_reference<U>::type value;
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typedef typename
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mpl::if_<is_convertible<T, value>, value, value const&>::type
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type;
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};
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template <typename U>
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BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
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typename result<replacer_if(U)>::type
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operator()(U const& x) const
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{
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return replacer_if_helper<is_convertible<T, U>::value>::
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call(x, f, new_value);
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}
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F f;
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T new_value;
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};
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}}}
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#endif
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