ceph/src/boost/boost/parameter/binding.hpp

   1 // Copyright David Abrahams 2005.
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifndef BOOST_PARAMETER_BINDING_DWA200558_HPP
   7 #define BOOST_PARAMETER_BINDING_DWA200558_HPP
   8
   9 #include <boost/parameter/aux_/void.hpp>
  10 #include <boost/parameter/config.hpp>
  11
  12 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  13 #include <boost/mp11/integral.hpp>
  14 #include <boost/mp11/list.hpp>
  15 #include <boost/mp11/utility.hpp>
  16 #include <type_traits>
  17 #else
  18 #include <boost/mpl/bool.hpp>
  19 #include <boost/mpl/if.hpp>
  20 #include <boost/mpl/eval_if.hpp>
  21 #include <boost/mpl/identity.hpp>
  22 #include <boost/mpl/apply_wrap.hpp>
  23 #include <boost/mpl/assert.hpp>
  24 #include <boost/type_traits/is_same.hpp>
  25 #endif
  26
  27 namespace boost { namespace parameter {
  28
  29     // A metafunction that, given an argument pack, returns the reference type
  30     // of the parameter identified by the given keyword.  If no such parameter
  31     // has been specified, returns Default
  32
  33     template <typename Parameters, typename Keyword, typename Default>
  34     struct binding0
  35     {
  36 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  37         using type = ::boost::mp11::mp_apply_q<
  38             typename Parameters::binding
  39           , ::boost::mp11::mp_list<Keyword,Default,::boost::mp11::mp_true>
  40         >;
  41
  42         static_assert(
  43             ::boost::mp11::mp_if<
  44                 ::std::is_same<Default,::boost::parameter::void_>
  45               , ::boost::mp11::mp_if<
  46                     ::std::is_same<type,::boost::parameter::void_>
  47                   , ::boost::mp11::mp_false
  48                   , ::boost::mp11::mp_true
  49                 >
  50               , ::boost::mp11::mp_true
  51             >::value
  52           , "required parameters must not result in void_ type"
  53         );
  54 #else   // !defined(BOOST_PARAMETER_CAN_USE_MP11)
  55         typedef typename ::boost::mpl::apply_wrap3<
  56             typename Parameters::binding
  57           , Keyword
  58           , Default
  59           , ::boost::mpl::true_
  60         >::type type;
  61
  62         BOOST_MPL_ASSERT((
  63             typename ::boost::mpl::eval_if<
  64                 ::boost::is_same<Default,::boost::parameter::void_>
  65               , ::boost::mpl::if_<
  66                     ::boost::is_same<type,::boost::parameter::void_>
  67                   , ::boost::mpl::false_
  68                   , ::boost::mpl::true_
  69                 >
  70               , ::boost::mpl::true_
  71             >::type
  72         ));
  73 #endif  // BOOST_PARAMETER_CAN_USE_MP11
  74     };
  75
  76 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
  77     template <typename Placeholder, typename Keyword, typename Default>
  78     struct binding1
  79     {
  80         using type = ::boost::mp11::mp_apply_q<
  81             Placeholder
  82           , ::boost::mp11::mp_list<Keyword,Default,::boost::mp11::mp_true>
  83         >;
  84
  85         static_assert(
  86             ::boost::mp11::mp_if<
  87                 ::std::is_same<Default,::boost::parameter::void_>
  88               , ::boost::mp11::mp_if<
  89                     ::std::is_same<type,::boost::parameter::void_>
  90                   , ::boost::mp11::mp_false
  91                   , ::boost::mp11::mp_true
  92                 >
  93               , ::boost::mp11::mp_true
  94             >::value
  95           , "required parameters must not result in void_ type"
  96         );
  97     };
  98 #endif  // BOOST_PARAMETER_CAN_USE_MP11
  99 }} // namespace boost::parameter
 100
 101 #include <boost/parameter/aux_/is_placeholder.hpp>
 102
 103 namespace boost { namespace parameter {
 104
 105     template <
 106         typename Parameters
 107       , typename Keyword
 108       , typename Default = ::boost::parameter::void_
 109     >
 110     struct binding
 111 #if !defined(BOOST_PARAMETER_CAN_USE_MP11)
 112       : ::boost::mpl::eval_if<
 113             ::boost::parameter::aux::is_mpl_placeholder<Parameters>
 114           , ::boost::mpl::identity<int>
 115           , ::boost::parameter::binding0<Parameters,Keyword,Default>
 116         >
 117 #endif
 118     {
 119 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
 120         using type = typename ::boost::mp11::mp_if<
 121             ::boost::parameter::aux::is_mpl_placeholder<Parameters>
 122           , ::boost::mp11::mp_identity<int>
 123           , ::boost::mp11::mp_if<
 124                 ::boost::parameter::aux::is_mp11_placeholder<Parameters>
 125               , ::boost::parameter::binding1<Parameters,Keyword,Default>
 126               , ::boost::parameter::binding0<Parameters,Keyword,Default>
 127             >
 128         >::type;
 129 #endif
 130     };
 131 }} // namespace boost::parameter
 132
 133 #include <boost/parameter/aux_/result_of0.hpp>
 134
 135 namespace boost { namespace parameter {
 136
 137     // A metafunction that, given an argument pack, returns the reference type
 138     // of the parameter identified by the given keyword.  If no such parameter
 139     // has been specified, returns the type returned by invoking DefaultFn
 140     template <typename Parameters, typename Keyword, typename DefaultFn>
 141     struct lazy_binding
 142     {
 143 #if defined(BOOST_PARAMETER_CAN_USE_MP11)
 144         using type = ::boost::mp11::mp_apply_q<
 145             typename Parameters::binding
 146           , ::boost::mp11::mp_list<
 147                 Keyword
 148               , typename ::boost::parameter::aux::result_of0<DefaultFn>::type
 149               , ::boost::mp11::mp_true
 150             >
 151         >;
 152 #else
 153         typedef typename ::boost::mpl::apply_wrap3<
 154             typename Parameters::binding
 155           , Keyword
 156           , typename ::boost::parameter::aux::result_of0<DefaultFn>::type
 157           , ::boost::mpl::true_
 158         >::type type;
 159 #endif  // BOOST_PARAMETER_CAN_USE_MP11
 160     };
 161 }} // namespace boost::parameter
 162
 163 #endif  // include guard
 164