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1 | /*============================================================================= |
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_HOLD_FEBRUARY_6_2010_0917AM) | |
8 | #define SPIRIT_HOLD_FEBRUARY_6_2010_0917AM | |
9 | ||
10 | #if defined(_MSC_VER) | |
11 | #pragma once | |
12 | #endif | |
13 | ||
14 | #include <boost/spirit/home/qi/meta_compiler.hpp> | |
15 | #include <boost/spirit/home/qi/skip_over.hpp> | |
16 | #include <boost/spirit/home/qi/parser.hpp> | |
17 | #include <boost/spirit/home/support/attributes.hpp> | |
18 | #include <boost/spirit/home/support/info.hpp> | |
19 | #include <boost/spirit/home/support/common_terminals.hpp> | |
20 | #include <boost/spirit/home/support/unused.hpp> | |
21 | #include <boost/spirit/home/support/has_semantic_action.hpp> | |
22 | #include <boost/spirit/home/support/handles_container.hpp> | |
23 | ||
24 | namespace boost { namespace spirit | |
25 | { | |
26 | /////////////////////////////////////////////////////////////////////////// | |
27 | // Enablers | |
28 | /////////////////////////////////////////////////////////////////////////// | |
29 | template <> | |
30 | struct use_directive<qi::domain, tag::hold> // enables hold | |
31 | : mpl::true_ {}; | |
32 | }} | |
33 | ||
34 | namespace boost { namespace spirit { namespace qi | |
35 | { | |
36 | #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS | |
37 | using spirit::hold; | |
38 | #endif | |
39 | using spirit::hold_type; | |
40 | ||
41 | template <typename Subject> | |
42 | struct hold_directive : unary_parser<hold_directive<Subject> > | |
43 | { | |
44 | typedef Subject subject_type; | |
45 | hold_directive(Subject const& subject_) | |
46 | : subject(subject_) {} | |
47 | ||
48 | template <typename Context, typename Iterator> | |
49 | struct attribute | |
50 | { | |
51 | typedef typename | |
52 | traits::attribute_of<subject_type, Context, Iterator>::type | |
53 | type; | |
54 | }; | |
55 | ||
56 | template <typename Iterator, typename Context | |
57 | , typename Skipper, typename Attribute> | |
58 | bool parse(Iterator& first, Iterator const& last | |
59 | , Context& context, Skipper const& skipper, Attribute& attr_) const | |
60 | { | |
61 | Attribute copy(attr_); | |
62 | if (subject.parse(first, last, context, skipper, copy)) | |
63 | { | |
64 | traits::swap_impl(copy, attr_); | |
65 | return true; | |
66 | } | |
67 | return false; | |
68 | } | |
69 | ||
70 | template <typename Context> | |
71 | info what(Context& context) const | |
72 | { | |
73 | return info("hold", subject.what(context)); | |
74 | ||
75 | } | |
76 | ||
77 | Subject subject; | |
78 | }; | |
79 | ||
80 | /////////////////////////////////////////////////////////////////////////// | |
81 | // Parser generators: make_xxx function (objects) | |
82 | /////////////////////////////////////////////////////////////////////////// | |
83 | template <typename Subject, typename Modifiers> | |
84 | struct make_directive<tag::hold, Subject, Modifiers> | |
85 | { | |
86 | typedef hold_directive<Subject> result_type; | |
87 | result_type operator()(unused_type, Subject const& subject, unused_type) const | |
88 | { | |
89 | return result_type(subject); | |
90 | } | |
91 | }; | |
92 | }}} | |
93 | ||
94 | namespace boost { namespace spirit { namespace traits | |
95 | { | |
96 | /////////////////////////////////////////////////////////////////////////// | |
97 | template <typename Subject> | |
98 | struct has_semantic_action<qi::hold_directive<Subject> > | |
99 | : unary_has_semantic_action<Subject> {}; | |
100 | ||
101 | /////////////////////////////////////////////////////////////////////////// | |
102 | template <typename Subject, typename Attribute, typename Context | |
103 | , typename Iterator> | |
104 | struct handles_container<qi::hold_directive<Subject>, Attribute | |
105 | , Context, Iterator> | |
106 | : unary_handles_container<Subject, Attribute, Context, Iterator> {}; | |
107 | }}} | |
108 | ||
109 | #endif |