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_KLEENE_MAR_03_2007_0337AM)
8 #define BOOST_SPIRIT_KARMA_KLEENE_MAR_03_2007_0337AM
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/output_iterator.hpp>
18 #include <boost/spirit/home/karma/detail/indirect_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/handles_container.hpp>
26 #include <boost/spirit/home/karma/detail/attributes.hpp>
27 #include <boost/proto/operators.hpp>
28 #include <boost/proto/tags.hpp>
29 #include <boost/type_traits/add_const.hpp>
30 
31 namespace boost { namespace spirit
32 {
33     ///////////////////////////////////////////////////////////////////////////
34     // Enablers
35     ///////////////////////////////////////////////////////////////////////////
36     template <>
37     struct use_operator<karma::domain, proto::tag::dereference> // enables *g
38       : mpl::true_ {};
39 }}
40 
41 ///////////////////////////////////////////////////////////////////////////////
42 namespace boost { namespace spirit { namespace karma
43 {
44     template <typename Subject, typename Strict, typename Derived>
45     struct base_kleene : unary_generator<Derived>
46     {
47     private:
48         // Ignore return value in relaxed mode (failing subject generators
49         // are just skipped). This allows to selectively generate items in
50         // the provided attribute.
51         template <typename F, typename Attribute>
generate_subjectboost::spirit::karma::base_kleene52         bool generate_subject(F f, Attribute const&, mpl::false_) const
53         {
54             bool r = !f(subject);
55             if (!r && !f.is_at_end())
56                 f.next();
57             return true;
58         }
59 
60         template <typename F, typename Attribute>
generate_subjectboost::spirit::karma::base_kleene61         bool generate_subject(F f, Attribute const&, mpl::true_) const
62         {
63             return !f(subject);
64         }
65 
66         // There is no way to distinguish a failed generator from a
67         // generator to be skipped. We assume the user takes responsibility
68         // for ending the loop if no attribute is specified.
69         template <typename F>
generate_subjectboost::spirit::karma::base_kleene70         bool generate_subject(F f, unused_type, mpl::false_) const
71         {
72             return !f(subject);
73         }
74 
75 //         template <typename F>
76 //         bool generate_subject(F f, unused_type, mpl::true_) const
77 //         {
78 //             return !f(subject);
79 //         }
80 
81     public:
82         typedef Subject subject_type;
83         typedef typename subject_type::properties properties;
84 
85         // Build a std::vector from the subject's attribute. Note
86         // that build_std_vector may return unused_type if the
87         // subject's attribute is an unused_type.
88         template <typename Context, typename Iterator>
89         struct attribute
90           : traits::build_std_vector<
91                 typename traits::attribute_of<Subject, Context, Iterator>::type
92             >
93         {};
94 
base_kleeneboost::spirit::karma::base_kleene95         base_kleene(Subject const& subject)
96           : subject(subject) {}
97 
98         template <
99             typename OutputIterator, typename Context, typename Delimiter
100           , typename Attribute>
generateboost::spirit::karma::base_kleene101         bool generate(OutputIterator& sink, Context& ctx
102           , Delimiter const& d, Attribute const& attr) const
103         {
104             typedef detail::fail_function<
105                 OutputIterator, Context, Delimiter> fail_function;
106 
107             typedef typename traits::container_iterator<
108                 typename add_const<Attribute>::type
109             >::type iterator_type;
110 
111             typedef
112                 typename traits::make_indirect_iterator<iterator_type>::type
113             indirect_iterator_type;
114             typedef detail::pass_container<
115                 fail_function, Attribute, indirect_iterator_type, mpl::false_>
116             pass_container;
117 
118             iterator_type it = traits::begin(attr);
119             iterator_type end = traits::end(attr);
120 
121             pass_container pass(fail_function(sink, ctx, d),
122                 indirect_iterator_type(it), indirect_iterator_type(end));
123 
124             // kleene fails only if the underlying output fails
125             while (!pass.is_at_end())
126             {
127                 if (!generate_subject(pass, attr, Strict()))
128                     break;
129             }
130             return detail::sink_is_good(sink);
131         }
132 
133         template <typename Context>
whatboost::spirit::karma::base_kleene134         info what(Context& context) const
135         {
136             return info("kleene", subject.what(context));
137         }
138 
139         Subject subject;
140     };
141 
142     template <typename Subject>
143     struct kleene
144       : base_kleene<Subject, mpl::false_, kleene<Subject> >
145     {
146         typedef base_kleene<Subject, mpl::false_, kleene> base_kleene_;
147 
kleeneboost::spirit::karma::kleene148         kleene(Subject const& subject)
149           : base_kleene_(subject) {}
150     };
151 
152     template <typename Subject>
153     struct strict_kleene
154       : base_kleene<Subject, mpl::true_, strict_kleene<Subject> >
155     {
156         typedef base_kleene<Subject, mpl::true_, strict_kleene> base_kleene_;
157 
strict_kleeneboost::spirit::karma::strict_kleene158         strict_kleene(Subject const& subject)
159           : base_kleene_(subject) {}
160     };
161 
162     ///////////////////////////////////////////////////////////////////////////
163     // Generator generators: make_xxx function (objects)
164     ///////////////////////////////////////////////////////////////////////////
165     namespace detail
166     {
167         template <typename Subject, bool strict_mode = false>
168         struct make_kleene
169           : make_unary_composite<Subject, kleene>
170         {};
171 
172         template <typename Subject>
173         struct make_kleene<Subject, true>
174           : make_unary_composite<Subject, strict_kleene>
175         {};
176     }
177 
178     template <typename Subject, typename Modifiers>
179     struct make_composite<proto::tag::dereference, Subject, Modifiers>
180       : detail::make_kleene<Subject, detail::get_stricttag<Modifiers>::value>
181     {};
182 }}}
183 
184 namespace boost { namespace spirit { namespace traits
185 {
186     ///////////////////////////////////////////////////////////////////////////
187     template <typename Subject>
188     struct has_semantic_action<karma::kleene<Subject> >
189       : unary_has_semantic_action<Subject> {};
190 
191     template <typename Subject>
192     struct has_semantic_action<karma::strict_kleene<Subject> >
193       : unary_has_semantic_action<Subject> {};
194 
195     ///////////////////////////////////////////////////////////////////////////
196     template <typename Subject, typename Attribute, typename Context
197       , typename Iterator>
198     struct handles_container<karma::kleene<Subject>, Attribute
199           , Context, Iterator>
200       : mpl::true_ {};
201 
202     template <typename Subject, typename Attribute, typename Context
203       , typename Iterator>
204     struct handles_container<karma::strict_kleene<Subject>, Attribute
205           , Context, Iterator>
206       : mpl::true_ {};
207 }}}
208 
209 #endif
210