/src/contrib/boost/spirit/home/support/has_semantic_action.hpp

 1/*=============================================================================
 2    Copyright (c) 2001-2010 Hartmut Kaiser
 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#if !defined(BOOST_SPIRIT_HAS_SEMANTIC_ACTION_SEP_20_2009_0626PM)
 8#define BOOST_SPIRIT_HAS_SEMANTIC_ACTION_SEP_20_2009_0626PM
 9
10#if defined(_MSC_VER)
11#pragma once
12#endif
13
14#include <boost/mpl/bool.hpp>
15#include <boost/mpl/or.hpp>
16#include <boost/mpl/not.hpp>
17#include <boost/mpl/find_if.hpp>
18#include <boost/type_traits/is_same.hpp>
19
20namespace boost { namespace spirit { namespace traits
21{
22    // finding out, whether a component contains a semantic action
23    template <typename T, typename Enable = void>
24    struct has_semantic_action
25      : mpl::false_ {};
26
27    template <typename Subject>
28    struct unary_has_semantic_action 
29      : has_semantic_action<Subject> {};
30
31    template <typename Left, typename Right>
32    struct binary_has_semantic_action 
33      : mpl::or_<has_semantic_action<Left>, has_semantic_action<Right> > {};
34
35    template <typename Elements>
36    struct nary_has_semantic_action
37      : mpl::not_<
38            is_same<
39                typename mpl::find_if<
40                    Elements, has_semantic_action<mpl::_> 
41                >::type
42              , typename mpl::end<Elements>::type
43            > 
44        > {};
45
46}}}
47
48#endif