1 /*==============================================================================
2 Copyright (c) 2005-2010 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 BOOST_PHOENIX_CORE_NOTHING_HPP
8 #define BOOST_PHOENIX_CORE_NOTHING_HPP
10 #include <boost/phoenix/core/limits.hpp>
11 #include <boost/mpl/void.hpp>
12 #include <boost/phoenix/core/actor.hpp>
13 #include <boost/phoenix/core/call.hpp>
14 #include <boost/phoenix/core/expression.hpp>
15 #include <boost/phoenix/core/value.hpp>
17 namespace boost { namespace phoenix
19 /////////////////////////////////////////////////////////////////////////////
23 // An actor that does nothing (a "bum", if you will :-).
25 /////////////////////////////////////////////////////////////////////////////
35 : expression::value<detail::nothing>
39 template<typename Dummy>
40 struct is_custom_terminal<detail::nothing, Dummy>
44 template<typename Dummy>
45 struct custom_terminal<detail::nothing, Dummy>
47 typedef void result_type;
48 template <typename Context>
49 void operator()(detail::nothing, Context &) const
54 typedef expression::null::type nothing_type BOOST_ATTRIBUTE_UNUSED;
55 #ifndef BOOST_PHOENIX_NO_PREDEFINED_TERMINALS
56 nothing_type const BOOST_ATTRIBUTE_UNUSED nothing = {{{}}};