ceph/src/boost/boost/spirit/home/x3/support/traits/is_substitute.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2014 Joel de Guzman
   3     http://spirit.sourceforge.net/
   4
   5     Distributed under the Boost Software License, Version 1.0. (See accompanying
   6     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7 =============================================================================*/
   8 #if !defined(BOOST_SPIRIT_X3_IS_SUBSTITUTE_JAN_9_2012_1049PM)
   9 #define BOOST_SPIRIT_X3_IS_SUBSTITUTE_JAN_9_2012_1049PM
  10
  11 #include <boost/spirit/home/x3/support/traits/container_traits.hpp>
  12 #include <boost/fusion/include/is_sequence.hpp>
  13 #include <boost/fusion/include/map.hpp>
  14 #include <boost/fusion/include/value_at_key.hpp>
  15 #include <boost/fusion/adapted/mpl.hpp>
  16 #include <boost/mpl/placeholders.hpp>
  17 #include <boost/mpl/equal.hpp>
  18 #include <boost/mpl/apply.hpp>
  19 #include <boost/mpl/filter_view.hpp>
  20 #include <boost/mpl/size.hpp>
  21 #include <boost/mpl/logical.hpp>
  22 #include <boost/mpl/at.hpp>
  23 #include <boost/mpl/count_if.hpp>
  24 #include <boost/utility/enable_if.hpp>
  25 #include <boost/optional/optional.hpp>
  26 #include <boost/type_traits/is_same.hpp>
  27
  28 namespace boost { namespace spirit { namespace x3 { namespace traits
  29 {
  30     ///////////////////////////////////////////////////////////////////////////
  31     // Find out if T can be a (strong) substitute for Attribute
  32     ///////////////////////////////////////////////////////////////////////////
  33     template <typename T, typename Attribute, typename Enable = void>
  34     struct is_substitute;
  35
  36     template <typename Variant, typename Attribute>
  37     struct variant_has_substitute;
  38
  39     namespace detail
  40     {
  41         template <typename T, typename Attribute>
  42         struct value_type_is_substitute
  43           : is_substitute<
  44                 typename container_value<T>::type
  45               , typename container_value<Attribute>::type>
  46         {};
  47
  48         template <typename T, typename Attribute, typename Enable = void>
  49         struct is_substitute_impl : mpl::false_ {};
  50
  51         template <typename T, typename Attribute>
  52         struct is_substitute_impl<T, Attribute,
  53             typename enable_if<
  54                 mpl::and_<
  55                     fusion::traits::is_sequence<T>,
  56                     fusion::traits::is_sequence<Attribute>,
  57                     mpl::equal<T, Attribute, is_substitute<mpl::_1, mpl::_2>>
  58                 >
  59             >::type>
  60           : mpl::true_ {};
  61
  62         template <typename T, typename Attribute>
  63         struct is_substitute_impl<T, Attribute,
  64             typename enable_if<
  65                 mpl::and_<
  66                     is_container<T>,
  67                     is_container<Attribute>,
  68                     value_type_is_substitute<T, Attribute>
  69                 >
  70             >::type>
  71           : mpl::true_ {};
  72
  73         template <typename T, typename Attribute>
  74         struct is_substitute_impl<T, Attribute,
  75             typename enable_if<
  76                 is_variant<Attribute>
  77             >::type>
  78           : variant_has_substitute<Attribute, T>
  79         {};
  80     }
  81
  82     template <typename T, typename Attribute, typename Enable /*= void*/>
  83     struct is_substitute
  84         : mpl::or_<
  85               is_same<T, Attribute>,
  86               detail::is_substitute_impl<T, Attribute>> {};
  87
  88     // for reference T
  89     template <typename T, typename Attribute, typename Enable>
  90     struct is_substitute<T&, Attribute, Enable>
  91         : is_substitute<T, Attribute, Enable> {};
  92
  93     // for reference Attribute
  94     template <typename T, typename Attribute, typename Enable>
  95     struct is_substitute<T, Attribute&, Enable>
  96         : is_substitute<T, Attribute, Enable> {};
  97
  98     // 2 element mpl tuple is compatible with fusion::map if:
  99     // - it's first element type is existing key in map
 100     // - it second element type is compatible to type stored at the key in map
 101     template <typename T, typename Attribute>
 102     struct is_substitute<T, Attribute
 103         , typename enable_if<
 104               typename mpl::eval_if<
 105                   mpl::and_<fusion::traits::is_sequence<T>
 106                             , fusion::traits::is_sequence<Attribute>>
 107                   , mpl::and_<traits::has_size<T, 2>
 108                            , fusion::traits::is_associative<Attribute>>
 109                   , mpl::false_>::type>::type>
 110
 111     {
 112         // checking that "p_key >> p_value" parser can
 113         // store it's result in fusion::map attribute
 114         typedef typename mpl::at_c<T, 0>::type p_key;
 115         typedef typename mpl::at_c<T, 1>::type p_value;
 116
 117         // for simple p_key type we just check that
 118         // such key can be found in attr and that value under that key
 119         // matches p_value
 120         template <typename Key, typename Value, typename Map>
 121         struct has_kv_in_map
 122             : mpl::eval_if<
 123                 fusion::result_of::has_key<Map, Key>
 124               , mpl::apply<
 125                     is_substitute<
 126                         fusion::result_of::value_at_key<mpl::_1, Key>
 127                       , Value>
 128                       , Map>
 129               , mpl::false_>
 130         {};
 131
 132         // if p_key is variant over multiple types (as a result of
 133         // "(key1|key2|key3) >> p_value" parser) check that all
 134         // keys are found in fusion::map attribute and that values
 135         // under these keys match p_value
 136         template <typename Variant>
 137         struct variant_kv
 138             : mpl::equal_to<
 139                 mpl::size< typename Variant::types>
 140               , mpl::size< mpl::filter_view<typename Variant::types
 141               , has_kv_in_map<mpl::_1, p_value, Attribute>>>
 142             >
 143         {};
 144
 145         typedef typename
 146             mpl::eval_if<
 147                 is_variant<p_key>
 148               , variant_kv<p_key>
 149               , has_kv_in_map<p_key, p_value, Attribute>
 150             >::type
 151         type;
 152     };
 153
 154     template <typename T, typename Attribute>
 155     struct is_substitute<optional<T>, optional<Attribute>>
 156       : is_substitute<T, Attribute> {};
 157 }}}}
 158
 159 #endif