1 /*=============================================================================
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_QI_OPERATOR_SEQUENTIAL_OR_HPP
8 #define BOOST_SPIRIT_QI_OPERATOR_SEQUENTIAL_OR_HPP
9 
10 #if defined(_MSC_VER)
11 #pragma once
12 #endif
13 
14 #include <boost/spirit/home/qi/meta_compiler.hpp>
15 #include <boost/spirit/home/qi/detail/pass_function.hpp>
16 #include <boost/spirit/home/qi/detail/attributes.hpp>
17 #include <boost/spirit/home/support/detail/what_function.hpp>
18 #include <boost/spirit/home/support/algorithm/any_if_ns_so.hpp>
19 #include <boost/spirit/home/support/handles_container.hpp>
20 #include <boost/fusion/include/as_vector.hpp>
21 #include <boost/fusion/include/for_each.hpp>
22 #include <boost/proto/operators.hpp>
23 #include <boost/proto/tags.hpp>
24 
25 namespace boost { namespace spirit
26 {
27     ///////////////////////////////////////////////////////////////////////////
28     // Enablers
29     ///////////////////////////////////////////////////////////////////////////
30     template <>
31     struct use_operator<qi::domain, proto::tag::logical_or> // enables ||
32       : mpl::true_ {};
33 
34     template <>
35     struct flatten_tree<qi::domain, proto::tag::logical_or> // flattens ||
36       : mpl::true_ {};
37 }}
38 
39 namespace boost { namespace spirit { namespace qi
40 {
41     template <typename Elements>
42     struct sequential_or : nary_parser<sequential_or<Elements> >
43     {
44         template <typename Context, typename Iterator>
45         struct attribute
46         {
47             // Put all the element attributes in a tuple,
48             // wrapping each element in a boost::optional
49             typedef typename traits::build_attribute_sequence<
50                 Elements, Context, traits::sequential_or_attribute_transform
51               , Iterator, qi::domain
52             >::type all_attributes;
53 
54             // Now, build a fusion vector over the attributes. Note
55             // that build_fusion_vector 1) removes all unused attributes
56             // and 2) may return unused_type if all elements have
57             // unused_type(s).
58             typedef typename
59                 traits::build_fusion_vector<all_attributes>::type
60             type;
61         };
62 
sequential_orboost::spirit::qi::sequential_or63         sequential_or(Elements const& elements_)
64           : elements(elements_) {}
65 
66         template <typename Iterator, typename Context
67           , typename Skipper, typename Attribute>
parseboost::spirit::qi::sequential_or68         bool parse(Iterator& first, Iterator const& last
69           , Context& context, Skipper const& skipper
70           , Attribute& attr_) const
71         {
72             typedef traits::attribute_not_unused<Context, Iterator> predicate;
73             detail::pass_function<Iterator, Context, Skipper>
74                 f(first, last, context, skipper);
75 
76             // wrap the attribute in a tuple if it is not a tuple
77             typename traits::wrap_if_not_tuple<Attribute>::type attr_local(attr_);
78 
79             // return true if *any* of the parsers succeed
80             // (we use the non-short-circuiting and strict order version:
81             // any_if_ns_so to force all the elements to be tested and
82             // in the defined order: first is first, last is last)
83             return spirit::any_if_ns_so(elements, attr_local, f, predicate());
84         }
85 
86         template <typename Context>
whatboost::spirit::qi::sequential_or87         info what(Context& context) const
88         {
89             info result("sequential-or");
90             fusion::for_each(elements,
91                 spirit::detail::what_function<Context>(result, context));
92             return result;
93         }
94 
95         Elements elements;
96     };
97 
98     ///////////////////////////////////////////////////////////////////////////
99     // Parser generators: make_xxx function (objects)
100     ///////////////////////////////////////////////////////////////////////////
101     template <typename Elements, typename Modifiers>
102     struct make_composite<proto::tag::logical_or, Elements, Modifiers>
103       : make_nary_composite<Elements, sequential_or>
104     {};
105 }}}
106 
107 namespace boost { namespace spirit { namespace traits
108 {
109     ///////////////////////////////////////////////////////////////////////////
110     // We specialize this for sequential_or (see support/attributes.hpp).
111     // For sequential_or, we only wrap the attribute in a tuple IFF
112     // it is not already a fusion tuple.
113     template <typename Elements, typename Attribute>
114     struct pass_attribute<qi::sequential_or<Elements>, Attribute>
115       : wrap_if_not_tuple<Attribute> {};
116 
117     ///////////////////////////////////////////////////////////////////////////
118     template <typename Elements>
119     struct has_semantic_action<qi::sequential_or<Elements> >
120       : nary_has_semantic_action<Elements> {};
121 
122     ///////////////////////////////////////////////////////////////////////////
123     template <typename Elements, typename Attribute, typename Context
124       , typename Iterator>
125     struct handles_container<qi::sequential_or<Elements>, Attribute, Context
126       , Iterator>
127       : nary_handles_container<Elements, Attribute, Context, Iterator> {};
128 }}}
129 
130 #endif
131