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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_QI_DETAIL_ATTRIBUTES_APR_18_2010_0458PM) | |
8 | #define SPIRIT_QI_DETAIL_ATTRIBUTES_APR_18_2010_0458PM | |
9 | ||
10 | #include <boost/spirit/home/qi/domain.hpp> | |
11 | #include <boost/spirit/home/support/attributes_fwd.hpp> | |
12 | #include <boost/spirit/home/support/attributes.hpp> | |
13 | #include <boost/spirit/home/support/utree/utree_traits_fwd.hpp> | |
14 | ||
15 | /////////////////////////////////////////////////////////////////////////////// | |
16 | namespace boost { namespace spirit { namespace qi | |
17 | { | |
18 | template <typename Exposed, typename Transformed> | |
19 | struct default_transform_attribute | |
20 | { | |
21 | typedef Transformed type; | |
22 | ||
23 | static Transformed pre(Exposed&) { return Transformed(); } | |
24 | ||
25 | static void post(Exposed& val, Transformed const& attr) | |
26 | { | |
27 | traits::assign_to(attr, val); | |
28 | } | |
29 | ||
30 | // fail() will be called by Qi rule's if the rhs failed parsing | |
31 | static void fail(Exposed&) {} | |
32 | }; | |
33 | ||
34 | // handle case where no transformation is required as the types are the same | |
35 | template <typename Attribute> | |
36 | struct default_transform_attribute<Attribute, Attribute> | |
37 | { | |
38 | typedef Attribute& type; | |
39 | static Attribute& pre(Attribute& val) { return val; } | |
40 | static void post(Attribute&, Attribute const&) {} | |
41 | static void fail(Attribute&) {} | |
42 | }; | |
43 | ||
44 | template <typename Exposed, typename Transformed> | |
45 | struct proxy_transform_attribute | |
46 | { | |
47 | typedef Transformed type; | |
48 | ||
49 | static Transformed pre(Exposed& val) { return Transformed(val); } | |
50 | static void post(Exposed&, Transformed const&) { /* no-op */ } | |
51 | ||
52 | // fail() will be called by Qi rule's if the rhs failed parsing | |
53 | static void fail(Exposed&) {} | |
54 | }; | |
55 | ||
56 | // handle case where no transformation is required as the types are the same | |
57 | template <typename Attribute> | |
58 | struct proxy_transform_attribute<Attribute, Attribute> | |
59 | { | |
60 | typedef Attribute& type; | |
61 | static Attribute& pre(Attribute& val) { return val; } | |
62 | static void post(Attribute&, Attribute const&) {} | |
63 | static void fail(Attribute&) {} | |
64 | }; | |
65 | ||
66 | // main specialization for Qi | |
67 | template <typename Exposed, typename Transformed, typename Enable = void> | |
68 | struct transform_attribute | |
69 | : mpl::if_< | |
70 | mpl::and_< | |
71 | mpl::not_<is_const<Exposed> > | |
72 | , mpl::not_<is_reference<Exposed> > | |
73 | , traits::is_proxy<Transformed> > | |
74 | , proxy_transform_attribute<Exposed, Transformed> | |
75 | , default_transform_attribute<Exposed, Transformed> | |
76 | >::type | |
77 | {}; | |
78 | ||
79 | template <typename Exposed, typename Transformed> | |
80 | struct transform_attribute<boost::optional<Exposed>, Transformed | |
81 | , typename disable_if<is_same<boost::optional<Exposed>, Transformed> >::type> | |
82 | { | |
83 | typedef Transformed& type; | |
84 | static Transformed& pre(boost::optional<Exposed>& val) | |
85 | { | |
86 | if (!val) | |
87 | val = Transformed(); | |
88 | return boost::get<Transformed>(val); | |
89 | } | |
90 | static void post(boost::optional<Exposed>&, Transformed const&) {} | |
91 | static void fail(boost::optional<Exposed>& val) | |
92 | { | |
93 | val = none; // leave optional uninitialized if rhs failed | |
94 | } | |
95 | }; | |
96 | ||
7c673cae FG |
97 | // unused_type needs some special handling as well |
98 | template <> | |
99 | struct transform_attribute<unused_type, unused_type> | |
100 | { | |
101 | typedef unused_type type; | |
102 | static unused_type pre(unused_type) { return unused; } | |
103 | static void post(unused_type, unused_type) {} | |
104 | static void fail(unused_type) {} | |
105 | }; | |
106 | ||
107 | template <> | |
108 | struct transform_attribute<unused_type const, unused_type> | |
109 | : transform_attribute<unused_type, unused_type> | |
110 | {}; | |
111 | ||
7c673cae FG |
112 | template <typename Attribute> |
113 | struct transform_attribute<Attribute, unused_type> | |
114 | : transform_attribute<unused_type, unused_type> | |
115 | {}; | |
116 | ||
117 | template <typename Attribute> | |
118 | struct transform_attribute<Attribute const, unused_type> | |
119 | : transform_attribute<unused_type, unused_type> | |
120 | {}; | |
121 | }}} | |
122 | ||
123 | /////////////////////////////////////////////////////////////////////////////// | |
124 | namespace boost { namespace spirit { namespace traits | |
125 | { | |
92f5a8d4 TL |
126 | namespace detail { |
127 | template <typename Exposed, typename Transformed> | |
128 | struct transform_attribute_base<Exposed, Transformed, qi::domain> | |
129 | : qi::transform_attribute<Exposed, Transformed> | |
130 | {}; | |
7c673cae FG |
131 | } |
132 | }}} | |
133 | ||
134 | #endif |