ceph/src/boost/boost/phoenix/core/is_nullary.hpp

   1 /*=============================================================================
   2     Copyright (c) 2005-2010 Joel de Guzman
   3     Copyright (c) 2010 Eric Niebler
   4     Copyright (c) 2010 Thomas Heller
   5
   6     Distributed under the Boost Software License, Version 1.0. (See accompanying
   7     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8 ==============================================================================*/
   9 #ifndef BOOST_PHOENIX_CORE_IS_NULLARY_HPP
  10 #define BOOST_PHOENIX_CORE_IS_NULLARY_HPP
  11
  12 #include <boost/phoenix/core/limits.hpp>
  13 #include <boost/phoenix/core/environment.hpp>
  14 #include <boost/phoenix/core/is_actor.hpp>
  15 #include <boost/phoenix/core/meta_grammar.hpp>
  16 #include <boost/phoenix/core/terminal_fwd.hpp>
  17 #include <boost/phoenix/support/vector.hpp>
  18 #include <boost/proto/transform/fold.hpp>
  19 #include <boost/proto/transform/lazy.hpp>
  20
  21 namespace boost { namespace phoenix
  22 {
  23     namespace result_of
  24     {
  25         template <typename Expr, typename Enable = void>
  26         struct is_nullary;
  27     }
  28
  29     struct is_nullary
  30     {
  31         template <typename Rule, typename Dummy = void>
  32         struct when
  33             : proto::fold<
  34                 proto::_
  35               , mpl::true_()
  36               , mpl::and_<
  37                     proto::_state
  38                   , proto::call<evaluator(proto::_, _context)>
  39                 >()
  40             >
  41         {};
  42     };
  43
  44     template <typename Dummy>
  45     struct is_nullary::when<rule::argument, Dummy>
  46     {
  47         BOOST_PROTO_TRANSFORM(is_nullary::when<rule::argument>)
  48         template <typename Expr, typename State, typename Data>
  49         struct impl
  50         {
  51             typedef mpl::false_ result_type;
  52         };
  53     };
  54
  55     template <
  56         typename Trait
  57       , typename Expr
  58       , typename State
  59       , typename Data
  60       , bool IsTransform = proto::is_transform<Trait>::value
  61     >
  62     struct is_nullary_custom_terminal_impl
  63     {
  64         typedef typename Trait::type result_type;
  65     };
  66
  67     template <typename Transform, typename Expr, typename State, typename Data>
  68     struct is_nullary_custom_terminal_impl<Transform, Expr, State, Data, true>
  69     {
  70         typedef
  71             typename Transform::template impl<
  72                 Expr
  73               , State
  74               , Data
  75             >::result_type
  76             result_type;
  77     };
  78
  79     template <typename Dummy>
  80     struct is_nullary::when<rule::custom_terminal, Dummy>
  81     {
  82         BOOST_PROTO_TRANSFORM(is_nullary::when<rule::custom_terminal>)
  83
  84         template <typename Expr, typename State, typename Data>
  85         struct impl
  86             : is_nullary_custom_terminal_impl<
  87                 result_of::is_nullary<
  88                     custom_terminal<
  89                         typename proto::detail::uncvref<
  90                             typename proto::result_of::value<Expr>::type
  91                         >::type
  92                     >
  93                 >
  94               , typename proto::result_of::value<Expr>::type
  95               , State
  96               , Data
  97             >
  98         {};
  99     };
 100
 101     template <typename Dummy>
 102     struct is_nullary::when<rule::terminal, Dummy>
 103     {
 104         BOOST_PROTO_TRANSFORM(is_nullary::when<rule::terminal>)
 105         template <typename Expr, typename State, typename Data>
 106         struct impl
 107         {
 108             typedef mpl::true_ result_type;
 109         };
 110     };
 111
 112     namespace result_of
 113     {
 114         template <typename Expr, typename Enable>
 115         struct is_nullary
 116             : boost::phoenix::evaluator::impl<
 117                 Expr const &
 118               , vector2<
 119                     mpl::true_
 120                   , boost::phoenix::is_nullary
 121                 >
 122               , proto::empty_env
 123             >::result_type
 124         {};
 125
 126         template <typename T>
 127         struct is_nullary<T & >
 128             : is_nullary<T>
 129         {};
 130
 131         template <typename T>
 132         struct is_nullary<T const & >
 133             : is_nullary<T>
 134         {};
 135
 136         template <typename T>
 137         struct is_nullary<T const >
 138             : is_nullary<T>
 139         {};
 140
 141         template <typename T>
 142         struct is_nullary<custom_terminal<T> >
 143             : mpl::true_
 144         {};
 145
 146         template <typename T>
 147         struct is_nullary<custom_terminal<actor<T> > >
 148             : evaluator
 149         {};
 150
 151         template <typename T>
 152         struct is_nullary<custom_terminal<boost::reference_wrapper<actor<T> > > >
 153         {
 154             BOOST_PROTO_TRANSFORM(is_nullary<custom_terminal<boost::reference_wrapper<actor<T> > > >)
 155             template <typename Expr, typename State, typename Data>
 156             struct impl
 157             {
 158                 typedef typename evaluator::template impl<actor<T>, State, Data>::result_type result_type;
 159             };
 160         };
 161
 162         template <typename T>
 163         struct is_nullary<custom_terminal<boost::reference_wrapper<actor<T> const> > >
 164         {
 165             BOOST_PROTO_TRANSFORM(is_nullary<custom_terminal<boost::reference_wrapper<actor<T> const> > >)
 166             template <typename Expr, typename State, typename Data>
 167             struct impl
 168             {
 169                 typedef typename evaluator::template impl<actor<T> const, State, Data>::result_type result_type;
 170             };
 171         };
 172     }
 173
 174 }}
 175
 176 #endif
 177