ceph/src/boost/libs/phoenix/include/boost/phoenix/core/is_actor.hpp

   1 /*==============================================================================
   2     Copyright (c) 2005-2010 Joel de Guzman
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 ==============================================================================*/
   7 #ifndef BOOST_PHOENIX_CORE_IS_ACTOR_HPP
   8 #define BOOST_PHOENIX_CORE_IS_ACTOR_HPP
   9
  10 #include <boost/mpl/bool.hpp>
  11
  12 // Note to Thomas and any future maintainer: please make this as
  13 // lightweight as possible (as it is right now).
  14
  15 namespace boost { namespace phoenix
  16 {
  17 ///////////////////////////////////////////////////////////////////////////////
  18 //
  19 //  is_actor<T>
  20 //
  21 //      Tests if T is an actor. Evaluates to mpl::true_ or mpl::false_
  22 //
  23 ///////////////////////////////////////////////////////////////////////////////
  24
  25     template <typename Expr>
  26     struct actor;
  27
  28     template <typename T, typename Enable = void>
  29     struct is_actor
  30         : mpl::false_
  31     {};
  32
  33     template <typename T>
  34     struct is_actor<T const>
  35         : is_actor<T>
  36     {};
  37
  38     template <typename T>
  39     struct is_actor<T &>
  40         : is_actor<T>
  41     {};
  42
  43     template <typename Expr>
  44     struct is_actor<actor<Expr> >
  45         : mpl::true_
  46     {};
  47 }}
  48
  49 #endif