1// Copyright (c) 2001-2011 Joel de Guzman
2// Copyright (c) 2001-2011 Hartmut Kaiser
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(BOOST_SPIRIT_KARMA_POSITIVE_MAR_03_2007_0945PM)
8#define BOOST_SPIRIT_KARMA_POSITIVE_MAR_03_2007_0945PM
9
10#if defined(_MSC_VER)
11#pragma once
12#endif
13
14#include <boost/spirit/home/karma/domain.hpp>
15#include <boost/spirit/home/karma/generator.hpp>
16#include <boost/spirit/home/karma/meta_compiler.hpp>
17#include <boost/spirit/home/karma/detail/indirect_iterator.hpp>
18#include <boost/spirit/home/karma/detail/output_iterator.hpp>
19#include <boost/spirit/home/karma/detail/get_stricttag.hpp>
20#include <boost/spirit/home/karma/detail/pass_container.hpp>
21#include <boost/spirit/home/karma/detail/fail_function.hpp>
22#include <boost/spirit/home/support/info.hpp>
23#include <boost/spirit/home/support/unused.hpp>
24#include <boost/spirit/home/support/container.hpp>
25#include <boost/spirit/home/support/has_semantic_action.hpp>
26#include <boost/spirit/home/support/handles_container.hpp>
27#include <boost/spirit/home/karma/detail/attributes.hpp>
28#include <boost/proto/operators.hpp>
29#include <boost/proto/tags.hpp>
30#include <boost/type_traits/add_const.hpp>
31
32namespace boost { namespace spirit
33{
34 ///////////////////////////////////////////////////////////////////////////
35 // Enablers
36 ///////////////////////////////////////////////////////////////////////////
37 template <>
38 struct use_operator<karma::domain, proto::tag::unary_plus> // enables +g
39 : mpl::true_ {};
40}}
41
42///////////////////////////////////////////////////////////////////////////////
43namespace boost { namespace spirit { namespace karma
44{
45 template <typename Subject, typename Strict, typename Derived>
46 struct base_plus : unary_generator<Derived>
47 {
48 private:
49 // Ignore return value in relaxed mode (failing subject generators
50 // are just skipped). This allows to selectively generate items in
51 // the provided attribute.
52 template <typename F, typename Attribute>
53 bool generate_subject(F f, Attribute const&, bool& result, mpl::false_) const
54 {
55 bool r = !f(subject);
56 if (r)
57 result = true;
58 else if (!f.is_at_end())
59 f.next();
60 return true;
61 }
62
63 template <typename F, typename Attribute>
64 bool generate_subject(F f, Attribute const&, bool& result, mpl::true_) const
65 {
66 bool r = !f(subject);
67 if (r)
68 result = true;
69 return r;
70 }
71
72 // There is no way to distinguish a failed generator from a
73 // generator to be skipped. We assume the user takes responsibility
74 // for ending the loop if no attribute is specified.
75 template <typename F>
76 bool generate_subject(F f, unused_type, bool& result, mpl::false_) const
77 {
78 bool r = f(subject);
79 if (!r)
80 result = true;
81 return !r;
82 }
83
84// template <typename F>
85// bool generate_subject(F f, unused_type, bool& result, mpl::true_) const
86// {
87// bool r = f(subject);
88// if (!r)
89// result = true;
90// return !r;
91// }
92
93 public:
94 typedef Subject subject_type;
95 typedef typename subject_type::properties properties;
96
97 // Build a std::vector from the subjects attribute. Note
98 // that build_std_vector may return unused_type if the
99 // subject's attribute is an unused_type.
100 template <typename Context, typename Iterator>
101 struct attribute
102 : traits::build_std_vector<
103 typename traits::attribute_of<subject_type, Context, Iterator>::type
104 >
105 {};
106
107 base_plus(Subject const& subject)
108 : subject(subject) {}
109
110 template <
111 typename OutputIterator, typename Context, typename Delimiter
112 , typename Attribute>
113 bool generate(OutputIterator& sink, Context& ctx
114 , Delimiter const& d, Attribute const& attr) const
115 {
116 typedef detail::fail_function<
117 OutputIterator, Context, Delimiter> fail_function;
118
119 typedef typename traits::container_iterator<
120 typename add_const<Attribute>::type
121 >::type iterator_type;
122
123 typedef
124 typename traits::make_indirect_iterator<iterator_type>::type
125 indirect_iterator_type;
126 typedef detail::pass_container<
127 fail_function, Attribute, indirect_iterator_type, mpl::false_>
128 pass_container;
129
130 iterator_type it = traits::begin(attr);
131 iterator_type end = traits::end(attr);
132
133 // plus fails if the parameter is empty
134 if (traits::compare(it, end))
135 return false;
136
137 pass_container pass(fail_function(sink, ctx, d),
138 indirect_iterator_type(it), indirect_iterator_type(end));
139
140 // from now on plus fails if the underlying output fails or overall
141 // no subject generators succeeded
142 bool result = false;
143 while (!pass.is_at_end())
144 {
145 if (!generate_subject(pass, attr, result, Strict()))
146 break;
147 }
148 return result && detail::sink_is_good(sink);
149 }
150
151 template <typename Context>
152 info what(Context& context) const
153 {
154 return info("plus", subject.what(context));
155 }
156
157 Subject subject;
158 };
159
160 template <typename Subject>
161 struct plus
162 : base_plus<Subject, mpl::false_, plus<Subject> >
163 {
164 typedef base_plus<Subject, mpl::false_, plus> base_plus_;
165
166 plus(Subject const& subject)
167 : base_plus_(subject) {}
168 };
169
170 template <typename Subject>
171 struct strict_plus
172 : base_plus<Subject, mpl::true_, strict_plus<Subject> >
173 {
174 typedef base_plus<Subject, mpl::true_, strict_plus> base_plus_;
175
176 strict_plus(Subject const& subject)
177 : base_plus_(subject) {}
178 };
179
180 ///////////////////////////////////////////////////////////////////////////
181 // Generator generators: make_xxx function (objects)
182 ///////////////////////////////////////////////////////////////////////////
183 namespace detail
184 {
185 template <typename Elements, bool strict_mode = false>
186 struct make_plus
187 : make_unary_composite<Elements, plus>
188 {};
189
190 template <typename Elements>
191 struct make_plus<Elements, true>
192 : make_unary_composite<Elements, strict_plus>
193 {};
194 }
195
196 template <typename Elements, typename Modifiers>
197 struct make_composite<proto::tag::unary_plus, Elements, Modifiers>
198 : detail::make_plus<Elements, detail::get_stricttag<Modifiers>::value>
199 {};
200}}}
201
202namespace boost { namespace spirit { namespace traits
203{
204 ///////////////////////////////////////////////////////////////////////////
205 template <typename Subject>
206 struct has_semantic_action<karma::plus<Subject> >
207 : unary_has_semantic_action<Subject> {};
208
209 template <typename Subject>
210 struct has_semantic_action<karma::strict_plus<Subject> >
211 : unary_has_semantic_action<Subject> {};
212
213 ///////////////////////////////////////////////////////////////////////////
214 template <typename Subject, typename Attribute, typename Context
215 , typename Iterator>
216 struct handles_container<karma::plus<Subject>, Attribute
217 , Context, Iterator>
218 : mpl::true_ {};
219
220 template <typename Subject, typename Attribute, typename Context
221 , typename Iterator>
222 struct handles_container<karma::strict_plus<Subject>, Attribute
223 , Context, Iterator>
224 : mpl::true_ {};
225}}}
226
227#endif
228

source code of boost/libs/spirit/include/boost/spirit/home/karma/operator/plus.hpp