1 | /*=============================================================================
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2 | Copyright (c) 2003 Joel de Guzman
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3 | Copyright (c) 2005 Eric Niebler
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4 |
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5 | Use, modification and distribution is subject to the Boost Software
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6 | License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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7 | http://www.boost.org/LICENSE_1_0.txt)
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8 | ==============================================================================*/
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9 | #if !defined(FUSION_ITERATOR_DETAIL_CONS_ITERATOR_DEREF_TRAITS_HPP)
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10 | #define FUSION_ITERATOR_DETAIL_CONS_ITERATOR_DEREF_TRAITS_HPP
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11 |
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12 | #include <boost/spirit/fusion/detail/config.hpp>
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13 | #include <boost/mpl/eval_if.hpp>
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14 | #include <boost/type_traits/is_const.hpp>
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15 | #include <boost/type_traits/add_const.hpp>
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16 | #include <boost/type_traits/add_reference.hpp>
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17 |
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18 | namespace boost { namespace fusion
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19 | {
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20 | struct cons_iterator_tag;
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21 |
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22 | namespace cons_detail
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23 | {
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24 | template <typename Iterator>
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25 | struct deref_traits_impl
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26 | {
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27 | typedef typename Iterator::cons_type cons_type;
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28 | typedef typename cons_type::car_type value_type;
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29 |
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30 | typedef typename mpl::eval_if<
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31 | is_const<cons_type>
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32 | , add_reference<typename add_const<value_type>::type>
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33 | , add_reference<value_type> >::type
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34 | type;
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35 |
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36 | static type
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37 | call(Iterator const& i)
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38 | {
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39 | return detail::ref(i.cons.car);
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40 | }
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41 | };
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42 | }
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43 |
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44 | namespace meta
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45 | {
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46 | template <typename Tag>
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47 | struct deref_impl;
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48 |
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49 | template <>
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50 | struct deref_impl<cons_iterator_tag>
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51 | {
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52 | template <typename Iterator>
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53 | struct apply : cons_detail::deref_traits_impl<Iterator> {};
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54 | };
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55 | }
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56 | }}
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57 |
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58 | #endif
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59 |
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60 |
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