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 #ifndef BOOST_SPIRIT_KARMA_OPERATOR_LIST_HPP
8 #define BOOST_SPIRIT_KARMA_OPERATOR_LIST_HPP
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 
30 namespace boost { namespace spirit
31 {
32     ///////////////////////////////////////////////////////////////////////////
33     // Enablers
34     ///////////////////////////////////////////////////////////////////////////
35     template <>
36     struct use_operator<karma::domain, proto::tag::modulus> // enables g % d
37       : mpl::true_ {};
38 }}
39 
40 ///////////////////////////////////////////////////////////////////////////////
41 namespace boost { namespace spirit { namespace karma
42 {
43     template <typename Left, typename Right, typename Strict, typename Derived>
44     struct base_list : binary_generator<Derived>
45     {
46     private:
47         // iterate over the given container until its exhausted or the embedded
48         // (left) generator succeeds
49         template <typename F, typename Attribute>
generate_leftboost::spirit::karma::base_list50         bool generate_left(F f, Attribute const&, mpl::false_) const
51         {
52             // Failing subject generators are just skipped. This allows to
53             // selectively generate items in the provided attribute.
54             while (!f.is_at_end())
55             {
56                 bool r = !f(left);
57                 if (r)
58                     return true;
59                 if (!f.is_at_end())
60                     f.next();
61             }
62             return false;
63         }
64 
65         template <typename F, typename Attribute>
generate_leftboost::spirit::karma::base_list66         bool generate_left(F f, Attribute const&, mpl::true_) const
67         {
68             return !f(left);
69         }
70 
71         // There is no way to distinguish a failed generator from a
72         // generator to be skipped. We assume the user takes responsibility
73         // for ending the loop if no attribute is specified.
74         template <typename F>
generate_leftboost::spirit::karma::base_list75         bool generate_left(F f, unused_type, mpl::false_) const
76         {
77             return !f(left);
78         }
79 
80     public:
81         typedef Left left_type;
82         typedef Right right_type;
83 
84         typedef mpl::int_<
85             left_type::properties::value
86           | right_type::properties::value
87           | generator_properties::buffering
88           | generator_properties::counting
89         > properties;
90 
91         // Build a std::vector from the LHS's attribute. Note
92         // that build_std_vector may return unused_type if the
93         // subject's attribute is an unused_type.
94         template <typename Context, typename Iterator>
95         struct attribute
96           : traits::build_std_vector<
97                 typename traits::attribute_of<Left, Context, Iterator>::type>
98         {};
99 
base_listboost::spirit::karma::base_list100         base_list(Left const& left, Right const& right)
101           : left(left), right(right)
102         {}
103 
104         template <
105             typename OutputIterator, typename Context, typename Delimiter
106           , typename Attribute>
generateboost::spirit::karma::base_list107         bool generate(OutputIterator& sink, Context& ctx
108           , Delimiter const& d, Attribute const& attr) const
109         {
110             typedef detail::fail_function<
111                 OutputIterator, Context, Delimiter
112             > fail_function;
113 
114             typedef typename traits::container_iterator<
115                 typename add_const<Attribute>::type
116             >::type iterator_type;
117 
118             typedef
119                 typename traits::make_indirect_iterator<iterator_type>::type
120             indirect_iterator_type;
121             typedef detail::pass_container<
122                 fail_function, Attribute, indirect_iterator_type, mpl::false_>
123             pass_container;
124 
125             iterator_type it = traits::begin(attr);
126             iterator_type end = traits::end(attr);
127 
128             pass_container pass(fail_function(sink, ctx, d),
129                 indirect_iterator_type(it), indirect_iterator_type(end));
130 
131             if (generate_left(pass, attr, Strict()))
132             {
133                 while (!pass.is_at_end())
134                 {
135                     // wrap the given output iterator as generate_left might fail
136                     detail::enable_buffering<OutputIterator> buffering(sink);
137                     {
138                         detail::disable_counting<OutputIterator> nocounting(sink);
139 
140                         if (!right.generate(sink, ctx, d, unused))
141                             return false;     // shouldn't happen
142 
143                         if (!generate_left(pass, attr, Strict()))
144                             break;            // return true as one item succeeded
145                     }
146                     buffering.buffer_copy();
147                 }
148                 return detail::sink_is_good(sink);
149             }
150             return false;
151         }
152 
153         template <typename Context>
whatboost::spirit::karma::base_list154         info what(Context& context) const
155         {
156             return info("list",
157                 std::make_pair(left.what(context), right.what(context)));
158         }
159 
160         Left left;
161         Right right;
162     };
163 
164     template <typename Left, typename Right>
165     struct list
166       : base_list<Left, Right, mpl::false_, list<Left, Right> >
167     {
168         typedef base_list<Left, Right, mpl::false_, list> base_list_;
169 
listboost::spirit::karma::list170         list(Left const& left, Right const& right)
171           : base_list_(left, right) {}
172     };
173 
174     template <typename Left, typename Right>
175     struct strict_list
176       : base_list<Left, Right, mpl::true_, strict_list<Left, Right> >
177     {
178         typedef base_list<Left, Right, mpl::true_, strict_list> base_list_;
179 
strict_listboost::spirit::karma::strict_list180         strict_list (Left const& left, Right const& right)
181           : base_list_(left, right) {}
182     };
183 
184     ///////////////////////////////////////////////////////////////////////////
185     // Generator generators: make_xxx function (objects)
186     ///////////////////////////////////////////////////////////////////////////
187     namespace detail
188     {
189         template <typename Subject, bool strict_mode = false>
190         struct make_list
191           : make_binary_composite<Subject, list>
192         {};
193 
194         template <typename Subject>
195         struct make_list<Subject, true>
196           : make_binary_composite<Subject, strict_list>
197         {};
198     }
199 
200     template <typename Subject, typename Modifiers>
201     struct make_composite<proto::tag::modulus, Subject, Modifiers>
202       : detail::make_list<Subject, detail::get_stricttag<Modifiers>::value>
203     {};
204 }}}
205 
206 namespace boost { namespace spirit { namespace traits
207 {
208     ///////////////////////////////////////////////////////////////////////////
209     template <typename Left, typename Right>
210     struct has_semantic_action<karma::list<Left, Right> >
211       : binary_has_semantic_action<Left, Right> {};
212 
213     template <typename Left, typename Right>
214     struct has_semantic_action<karma::strict_list<Left, Right> >
215       : binary_has_semantic_action<Left, Right> {};
216 
217     ///////////////////////////////////////////////////////////////////////////
218     template <typename Left, typename Right, typename Attribute
219       , typename Context, typename Iterator>
220     struct handles_container<karma::list<Left, Right>, Attribute
221           , Context, Iterator>
222       : mpl::true_ {};
223 
224     template <typename Left, typename Right, typename Attribute
225       , typename Context, typename Iterator>
226     struct handles_container<karma::strict_list<Left, Right>, Attribute
227           , Context, Iterator>
228       : mpl::true_ {};
229 }}}
230 
231 #endif
232