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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(SPIRIT_KARMA_OMIT_JUL_20_2009_1008AM) | |
7 | #define SPIRIT_KARMA_OMIT_JUL_20_2009_1008AM | |
8 | ||
9 | #if defined(_MSC_VER) | |
10 | #pragma once | |
11 | #endif | |
12 | ||
13 | #include <boost/spirit/home/karma/meta_compiler.hpp> | |
14 | #include <boost/spirit/home/karma/generator.hpp> | |
15 | #include <boost/spirit/home/karma/domain.hpp> | |
16 | #include <boost/spirit/home/support/unused.hpp> | |
17 | #include <boost/spirit/home/support/info.hpp> | |
18 | #include <boost/spirit/home/support/common_terminals.hpp> | |
19 | #include <boost/spirit/home/support/has_semantic_action.hpp> | |
20 | #include <boost/spirit/home/support/handles_container.hpp> | |
21 | #include <boost/spirit/home/karma/detail/attributes.hpp> | |
22 | ||
23 | namespace boost { namespace spirit | |
24 | { | |
25 | /////////////////////////////////////////////////////////////////////////// | |
26 | // Enablers | |
27 | /////////////////////////////////////////////////////////////////////////// | |
28 | template <> | |
29 | struct use_directive<karma::domain, tag::omit> // enables omit | |
30 | : mpl::true_ {}; | |
31 | ||
32 | template <> | |
33 | struct use_directive<karma::domain, tag::skip> // enables skip | |
34 | : mpl::true_ {}; | |
35 | }} | |
36 | ||
37 | namespace boost { namespace spirit { namespace karma | |
38 | { | |
39 | #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS | |
40 | using spirit::omit; | |
41 | using spirit::skip; | |
42 | #endif | |
43 | using spirit::omit_type; | |
44 | using spirit::skip_type; | |
45 | ||
46 | /////////////////////////////////////////////////////////////////////////// | |
47 | // omit_directive consumes the attribute of subject generator without | |
48 | // generating anything | |
49 | /////////////////////////////////////////////////////////////////////////// | |
50 | template <typename Subject, bool Execute> | |
51 | struct omit_directive : unary_generator<omit_directive<Subject, Execute> > | |
52 | { | |
53 | typedef Subject subject_type; | |
54 | ||
55 | typedef mpl::int_< | |
56 | generator_properties::disabling | subject_type::properties::value | |
57 | > properties; | |
58 | ||
59 | omit_directive(Subject const& subject) | |
60 | : subject(subject) {} | |
61 | ||
62 | template <typename Context, typename Iterator = unused_type> | |
63 | struct attribute | |
64 | : traits::attribute_of<subject_type, Context, Iterator> | |
65 | {}; | |
66 | ||
67 | template <typename OutputIterator, typename Context, typename Delimiter | |
68 | , typename Attribute> | |
69 | bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d | |
70 | , Attribute const& attr) const | |
71 | { | |
72 | // We need to actually compile the output operation as we don't | |
73 | // have any other means to verify, whether the passed attribute is | |
74 | // compatible with the subject. | |
75 | ||
76 | // omit[] will execute the code, while skip[] doesn't execute it | |
77 | if (Execute) { | |
78 | // wrap the given output iterator to avoid output | |
79 | detail::disable_output<OutputIterator> disable(sink); | |
80 | return subject.generate(sink, ctx, d, attr); | |
81 | } | |
82 | return true; | |
83 | } | |
84 | ||
85 | template <typename Context> | |
86 | info what(Context& context) const | |
87 | { | |
88 | return info(Execute ? "omit" : "skip", subject.what(context)); | |
89 | } | |
90 | ||
91 | Subject subject; | |
92 | }; | |
93 | ||
94 | /////////////////////////////////////////////////////////////////////////// | |
95 | // Generator generators: make_xxx function (objects) | |
96 | /////////////////////////////////////////////////////////////////////////// | |
97 | template <typename Subject, typename Modifiers> | |
98 | struct make_directive<tag::omit, Subject, Modifiers> | |
99 | { | |
100 | typedef omit_directive<Subject, true> result_type; | |
101 | result_type operator()(unused_type, Subject const& subject | |
102 | , unused_type) const | |
103 | { | |
104 | return result_type(subject); | |
105 | } | |
106 | }; | |
107 | ||
108 | template <typename Subject, typename Modifiers> | |
109 | struct make_directive<tag::skip, Subject, Modifiers> | |
110 | { | |
111 | typedef omit_directive<Subject, false> result_type; | |
112 | result_type operator()(unused_type, Subject const& subject | |
113 | , unused_type) const | |
114 | { | |
115 | return result_type(subject); | |
116 | } | |
117 | }; | |
118 | }}} | |
119 | ||
120 | namespace boost { namespace spirit { namespace traits | |
121 | { | |
122 | /////////////////////////////////////////////////////////////////////////// | |
123 | template <typename Subject, bool Execute> | |
124 | struct has_semantic_action<karma::omit_directive<Subject, Execute> > | |
125 | : unary_has_semantic_action<Subject> {}; | |
126 | ||
127 | /////////////////////////////////////////////////////////////////////////// | |
128 | template <typename Subject, bool Execute, typename Attribute | |
129 | , typename Context, typename Iterator> | |
130 | struct handles_container<karma::omit_directive<Subject, Execute>, Attribute | |
131 | , Context, Iterator> | |
132 | : unary_handles_container<Subject, Attribute, Context, Iterator> {}; | |
133 | }}} | |
134 | ||
135 | #endif |