1 /*=============================================================================
2 Copyright (c) 2001-2007 Joel de Guzman
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_NOTHING_HPP
8 #define PHOENIX_CORE_NOTHING_HPP
10 #include <boost/spirit/home/phoenix/core/actor.hpp>
11 #include <boost/mpl/bool.hpp>
13 namespace boost { namespace phoenix
15 ///////////////////////////////////////////////////////////////////////////////
19 // A actor that does nothing (a "bum", if you will :-).
21 ///////////////////////////////////////////////////////////////////////////////
24 typedef mpl::false_ no_nullary;
26 template <typename Env>
32 template <typename Env>
34 eval(Env const&) const
39 actor<null_actor> const nothing = null_actor();