boost/spirit/home/phoenix/core/as_actor.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2007 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 PHOENIX_CORE_AS_ACTOR_HPP
   8 #define PHOENIX_CORE_AS_ACTOR_HPP
   9
  10 #include <boost/spirit/home/phoenix/core/actor.hpp>
  11
  12 namespace boost { namespace phoenix
  13 {
  14     template <typename T>
  15     struct as_actor_base; // defined in value.hpp
  16
  17     template <typename Base>
  18     struct as_actor_base<actor<Base> >
  19     {
  20         typedef Base type;
  21
  22         static Base const&
  23         convert(actor<Base> const& x)
  24         {
  25             return x;
  26         }
  27     };
  28
  29     template <>
  30     struct as_actor_base<fusion::void_>
  31     {
  32         typedef fusion::void_ type;
  33         struct error_attempting_to_convert_void_type_to_an_actor {};
  34
  35         static void
  36         convert(error_attempting_to_convert_void_type_to_an_actor);
  37     };
  38
  39     template <>
  40     struct as_actor_base<void>
  41     {
  42         typedef void type;
  43         struct error_attempting_to_convert_void_type_to_an_actor {};
  44
  45         static void
  46         convert(error_attempting_to_convert_void_type_to_an_actor);
  47     };
  48
  49     template <typename T>
  50     struct as_actor
  51     {
  52         typedef actor<typename as_actor_base<T>::type> type;
  53
  54         static type
  55         convert(T const& x)
  56         {
  57             return as_actor_base<T>::convert(x);
  58         }
  59     };
  60 }}
  61
  62 #endif