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 #if !defined(SPIRIT_KARMA_ALTERNATIVE_MAR_01_2007_1117AM)
8 #define SPIRIT_KARMA_ALTERNATIVE_MAR_01_2007_1117AM
9 
10 #if defined(_MSC_VER)
11 #pragma once
12 #endif
13 
14 #include <boost/spirit/home/karma/detail/alternative_function.hpp>
15 #include <boost/spirit/home/karma/detail/get_stricttag.hpp>
16 #include <boost/spirit/home/karma/domain.hpp>
17 #include <boost/spirit/home/karma/generator.hpp>
18 #include <boost/spirit/home/karma/meta_compiler.hpp>
19 #include <boost/spirit/home/support/info.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 #include <boost/spirit/home/support/detail/what_function.hpp>
24 #include <boost/fusion/include/any.hpp>
25 #include <boost/fusion/include/mpl.hpp>
26 #include <boost/fusion/include/for_each.hpp>
27 #include <boost/mpl/accumulate.hpp>
28 #include <boost/mpl/bitor.hpp>
29 #include <boost/config.hpp>
30 
31 namespace boost { namespace spirit
32 {
33     ///////////////////////////////////////////////////////////////////////////
34     // Enablers
35     ///////////////////////////////////////////////////////////////////////////
36     template <>
37     struct use_operator<karma::domain, proto::tag::bitwise_or>  // enables |
38       : mpl::true_ {};
39 
40     template <>
41     struct flatten_tree<karma::domain, proto::tag::bitwise_or>  // flattens |
42       : mpl::true_ {};
43 
44 }}
45 
46 ///////////////////////////////////////////////////////////////////////////////
47 namespace boost { namespace spirit { namespace traits
48 {
49     // specialization for sequences
50     template <typename Elements>
51     struct alternative_properties
52     {
53         struct element_properties
54         {
55             template <typename T>
56             struct result;
57 
58             template <typename F, typename Element>
59             struct result<F(Element)>
60             {
61                 typedef properties_of<Element> type;
62             };
63 
64             // never called, but needed for decltype-based result_of (C++0x)
65 #ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
66             template <typename Element>
67             typename result<element_properties(Element)>::type
68             operator()(Element&&) const;
69 #endif
70         };
71 
72         typedef typename mpl::accumulate<
73             typename fusion::result_of::transform<
74                 Elements, element_properties>::type
75           , mpl::int_<karma::generator_properties::countingbuffer>
76           , mpl::bitor_<mpl::_2, mpl::_1>
77         >::type type;
78     };
79 
80 }}}
81 
82 namespace boost { namespace spirit { namespace karma
83 {
84     template <typename Elements, typename Strict, typename Derived>
85     struct base_alternative : nary_generator<Derived>
86     {
87         typedef typename traits::alternative_properties<Elements>::type
88             properties;
89 
90         template <typename Context, typename Iterator = unused_type>
91         struct attribute
92         {
93             // Put all the element attributes in a tuple
94             typedef typename traits::build_attribute_sequence<
95                 Elements, Context, traits::alternative_attribute_transform
96               , Iterator, karma::domain
97             >::type all_attributes;
98 
99             // Ok, now make a variant over the attribute sequence. Note that
100             // build_variant makes sure that 1) all attributes in the variant
101             // are unique 2) puts the unused attribute, if there is any, to
102             // the front and 3) collapses single element variants, variant<T>
103             // to T.
104             typedef typename traits::build_variant<all_attributes>::type type;
105         };
106 
base_alternativeboost::spirit::karma::base_alternative107         base_alternative(Elements const& elements)
108           : elements(elements) {}
109 
110         template <
111             typename OutputIterator, typename Context, typename Delimiter
112           , typename Attribute>
generateboost::spirit::karma::base_alternative113         bool generate(OutputIterator& sink, Context& ctx
114           , Delimiter const& d, Attribute const& attr) const
115         {
116             typedef detail::alternative_generate_function<
117                 OutputIterator, Context, Delimiter, Attribute, Strict
118             > functor;
119 
120             // f return true if *any* of the parser succeeds
121             functor f (sink, ctx, d, attr);
122             return fusion::any(elements, f);
123         }
124 
125         template <typename Context>
whatboost::spirit::karma::base_alternative126         info what(Context& context) const
127         {
128             info result("alternative");
129             fusion::for_each(elements,
130                 spirit::detail::what_function<Context>(result, context));
131             return result;
132         }
133 
134         Elements elements;
135     };
136 
137     template <typename Elements>
138     struct alternative
139       : base_alternative<Elements, mpl::false_, alternative<Elements> >
140     {
141         typedef base_alternative<Elements, mpl::false_, alternative>
142             base_alternative_;
143 
alternativeboost::spirit::karma::alternative144         alternative(Elements const& elements)
145           : base_alternative_(elements) {}
146     };
147 
148     template <typename Elements>
149     struct strict_alternative
150       : base_alternative<Elements, mpl::true_, strict_alternative<Elements> >
151     {
152         typedef base_alternative<Elements, mpl::true_, strict_alternative>
153             base_alternative_;
154 
strict_alternativeboost::spirit::karma::strict_alternative155         strict_alternative(Elements const& elements)
156           : base_alternative_(elements) {}
157     };
158 
159     ///////////////////////////////////////////////////////////////////////////
160     // Generator generators: make_xxx function (objects)
161     ///////////////////////////////////////////////////////////////////////////
162     namespace detail
163     {
164         template <typename Elements, bool strict_mode = false>
165         struct make_alternative
166           : make_nary_composite<Elements, alternative>
167         {};
168 
169         template <typename Elements>
170         struct make_alternative<Elements, true>
171           : make_nary_composite<Elements, strict_alternative>
172         {};
173     }
174 
175     template <typename Elements, typename Modifiers>
176     struct make_composite<proto::tag::bitwise_or, Elements, Modifiers>
177       : detail::make_alternative<Elements
178           , detail::get_stricttag<Modifiers>::value>
179     {};
180 
181 }}}
182 
183 namespace boost { namespace spirit { namespace traits
184 {
185     ///////////////////////////////////////////////////////////////////////////
186     template <typename Elements>
187     struct has_semantic_action<karma::alternative<Elements> >
188       : nary_has_semantic_action<Elements> {};
189 
190     template <typename Elements>
191     struct has_semantic_action<karma::strict_alternative<Elements> >
192       : nary_has_semantic_action<Elements> {};
193 
194     ///////////////////////////////////////////////////////////////////////////
195     template <typename Elements, typename Attribute, typename Context
196       , typename Iterator>
197     struct handles_container<karma::alternative<Elements>
198           , Attribute, Context, Iterator>
199       : nary_handles_container<Elements, Attribute, Context, Iterator> {};
200 
201     template <typename Elements, typename Attribute, typename Context
202       , typename Iterator>
203     struct handles_container<karma::strict_alternative<Elements>
204           , Attribute, Context, Iterator>
205       : nary_handles_container<Elements, Attribute, Context, Iterator> {};
206 }}}
207 
208 #endif
209