1 //  Copyright (c) 2001-2011 Hartmut Kaiser
2 //  Copyright (c) 2001-2011 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 #if !defined(SPIRIT_KARMA_DETAIL_ATTRIBUTES_APR_18_2010_0453PM)
8 #define SPIRIT_KARMA_DETAIL_ATTRIBUTES_APR_18_2010_0453PM
9 
10 #include <boost/spirit/home/karma/domain.hpp>
11 #include <boost/spirit/home/support/attributes_fwd.hpp>
12 #include <boost/spirit/home/support/attributes.hpp>
13 
14 ///////////////////////////////////////////////////////////////////////////////
15 namespace boost { namespace spirit { namespace karma
16 {
17     template <typename Exposed, typename Transformed, typename Enable = void>
18     struct transform_attribute
19     {
20         typedef Transformed type;
preboost::spirit::karma::transform_attribute21         static Transformed pre(Exposed& val)
22         {
23             return Transformed(traits::extract_from<Transformed>(val, unused));
24         }
25         // Karma only, no post() and no fail() required
26     };
27 
28     template <typename Exposed, typename Transformed>
29     struct transform_attribute<boost::optional<Exposed> const, Transformed
30       , typename disable_if<is_same<boost::optional<Exposed>, Transformed> >::type>
31     {
32         typedef Transformed const& type;
preboost::spirit::karma::disable_if::type33         static Transformed const& pre(boost::optional<Exposed> const& val)
34         {
35             return boost::get<Transformed>(val);
36         }
37     };
38 
39     template <typename Attribute>
40     struct transform_attribute<Attribute const, Attribute>
41     {
42         typedef Attribute const& type;
preboost::spirit::karma::transform_attribute43         static Attribute const& pre(Attribute const& val) { return val; }
44         // Karma only, no post() and no fail() required
45     };
46 
47     // reference types need special handling
48     template <typename Exposed, typename Transformed>
49     struct transform_attribute<Exposed&, Transformed>
50       : transform_attribute<Exposed, Transformed>
51     {};
52 
53     template <typename Exposed, typename Transformed>
54     struct transform_attribute<Exposed const&, Transformed>
55       : transform_attribute<Exposed const, Transformed>
56     {};
57 
58     template <typename Attribute>
59     struct transform_attribute<Attribute const&, Attribute>
60       : transform_attribute<Attribute const, Attribute>
61     {};
62 
63     // unused_type needs some special handling as well
64     template <>
65     struct transform_attribute<unused_type, unused_type>
66     {
67         typedef unused_type type;
preboost::spirit::karma::transform_attribute68         static unused_type pre(unused_type) { return unused; }
69     };
70 
71     template <>
72     struct transform_attribute<unused_type const, unused_type>
73       : transform_attribute<unused_type, unused_type>
74     {};
75 
76     template <typename Attribute>
77     struct transform_attribute<unused_type, Attribute>
78       : transform_attribute<unused_type, unused_type>
79     {};
80 
81     template <typename Attribute>
82     struct transform_attribute<unused_type const, Attribute>
83       : transform_attribute<unused_type, unused_type>
84     {};
85 
86     template <typename Attribute>
87     struct transform_attribute<Attribute, unused_type>
88       : transform_attribute<unused_type, unused_type>
89     {};
90 
91     template <typename Attribute>
92     struct transform_attribute<Attribute const, unused_type>
93       : transform_attribute<unused_type, unused_type>
94     {};
95 }}}
96 
97 ///////////////////////////////////////////////////////////////////////////////
98 namespace boost { namespace spirit { namespace traits
99 {
100     template <typename Exposed, typename Transformed>
101     struct transform_attribute<Exposed, Transformed, karma::domain>
102       : karma::transform_attribute<Exposed, Transformed>
103     {};
104 }}}
105 
106 #endif
107 
108 
109