/Src/Dependencies/Boost/boost/spirit/home/karma/detail/as.hpp

 1//  Copyright (c) 2001-2011 Hartmut Kaiser
 2//
 3//  Distributed under the Boost Software License, Version 1.0. (See accompanying
 4//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 5
 6#if !defined(BOOST_SPIRIT_KARMA_AS_STRING_DEC_18_0644PM)
 7#define BOOST_SPIRIT_KARMA_AS_STRING_DEC_18_0644PM
 8
 9#if defined(_MSC_VER)
10#pragma once
11#endif
12
13#include <boost/spirit/home/support/unused.hpp>
14#include <boost/spirit/home/support/attributes_fwd.hpp>
15
16///////////////////////////////////////////////////////////////////////////////
17namespace boost { namespace spirit { namespace traits
18{
19    ///////////////////////////////////////////////////////////////////////////
20    //  This file contains the attribute to string conversion utility. The 
21    //  utility provided also accept spirit's unused_type; all no-ops. Compiler 
22    //  optimization will easily strip these away.
23    ///////////////////////////////////////////////////////////////////////////
24
25    ///////////////////////////////////////////////////////////////////////////
26    template <typename T, typename Attribute>
27    inline typename spirit::result_of::attribute_as<T, Attribute>::type
28    as(Attribute const& attr)
29    {
30        return attribute_as<T, Attribute>::call(attr);
31    }
32
33    template <typename T>
34    inline unused_type as(unused_type)
35    {
36        return unused;
37    }
38    
39    ///////////////////////////////////////////////////////////////////////////
40    template <typename T, typename Attribute>
41    inline bool valid_as(Attribute const& attr)
42    {
43        return attribute_as<T, Attribute>::is_valid(attr);
44    }
45
46    template <typename T>
47    inline bool valid_as(unused_type)
48    {
49        return true;
50    }
51}}}
52
53///////////////////////////////////////////////////////////////////////////////
54namespace boost { namespace spirit { namespace result_of
55{
56    template <typename T, typename Attribute>
57    struct attribute_as
58      : traits::attribute_as<T, Attribute>
59    {};
60
61    template <typename T>
62    struct attribute_as<T, unused_type>
63    {
64        typedef unused_type type;
65    };
66
67    template <typename T>
68    struct attribute_as<T, unused_type const>
69    {
70        typedef unused_type type;
71    };
72}}}
73
74#endif