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 #if !defined(SPIRIT_SEQUENTIAL_OR_MARCH_12_2007_1130PM)
8 #define SPIRIT_SEQUENTIAL_OR_MARCH_12_2007_1130PM
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 
23 namespace boost { namespace spirit
24 {
25     ///////////////////////////////////////////////////////////////////////////
26     // Enablers
27     ///////////////////////////////////////////////////////////////////////////
28     template <>
29     struct use_operator<qi::domain, proto::tag::logical_or> // enables ||
30       : mpl::true_ {};
31 
32     template <>
33     struct flatten_tree<qi::domain, proto::tag::logical_or> // flattens ||
34       : mpl::true_ {};
35 }}
36 
37 namespace boost { namespace spirit { namespace qi
38 {
39     template <typename Elements>
40     struct sequential_or : nary_parser<sequential_or<Elements> >
41     {
42         template <typename Context, typename Iterator>
43         struct attribute
44         {
45             // Put all the element attributes in a tuple,
46             // wrapping each element in a boost::optional
47             typedef typename traits::build_attribute_sequence<
48                 Elements, Context, traits::sequential_or_attribute_transform
49               , Iterator, qi::domain
50             >::type all_attributes;
51 
52             // Now, build a fusion vector over the attributes. Note
53             // that build_fusion_vector 1) removes all unused attributes
54             // and 2) may return unused_type if all elements have
55             // unused_type(s).
56             typedef typename
57                 traits::build_fusion_vector<all_attributes>::type
58             type;
59         };
60 
sequential_orboost::spirit::qi::sequential_or61         sequential_or(Elements const& elements_)
62           : elements(elements_) {}
63 
64         template <typename Iterator, typename Context
65           , typename Skipper, typename Attribute>
parseboost::spirit::qi::sequential_or66         bool parse(Iterator& first, Iterator const& last
67           , Context& context, Skipper const& skipper
68           , Attribute& attr_) const
69         {
70             typedef traits::attribute_not_unused<Context, Iterator> predicate;
71             detail::pass_function<Iterator, Context, Skipper>
72                 f(first, last, context, skipper);
73 
74             // wrap the attribute in a tuple if it is not a tuple
75             typename traits::wrap_if_not_tuple<Attribute>::type attr_local(attr_);
76 
77             // return true if *any* of the parsers succeed
78             // (we use the non-short-circuiting and strict order version:
79             // any_if_ns_so to force all the elements to be tested and
80             // in the defined order: first is first, last is last)
81             return spirit::any_if_ns_so(elements, attr_local, f, predicate());
82         }
83 
84         template <typename Context>
whatboost::spirit::qi::sequential_or85         info what(Context& context) const
86         {
87             info result("sequential-or");
88             fusion::for_each(elements,
89                 spirit::detail::what_function<Context>(result, context));
90             return result;
91         }
92 
93         Elements elements;
94     };
95 
96     ///////////////////////////////////////////////////////////////////////////
97     // Parser generators: make_xxx function (objects)
98     ///////////////////////////////////////////////////////////////////////////
99     template <typename Elements, typename Modifiers>
100     struct make_composite<proto::tag::logical_or, Elements, Modifiers>
101       : make_nary_composite<Elements, sequential_or>
102     {};
103 }}}
104 
105 namespace boost { namespace spirit { namespace traits
106 {
107     ///////////////////////////////////////////////////////////////////////////
108     // We specialize this for sequential_or (see support/attributes.hpp).
109     // For sequential_or, we only wrap the attribute in a tuple IFF
110     // it is not already a fusion tuple.
111     template <typename Elements, typename Attribute>
112     struct pass_attribute<qi::sequential_or<Elements>, Attribute>
113       : wrap_if_not_tuple<Attribute> {};
114 
115     ///////////////////////////////////////////////////////////////////////////
116     template <typename Elements>
117     struct has_semantic_action<qi::sequential_or<Elements> >
118       : nary_has_semantic_action<Elements> {};
119 
120     ///////////////////////////////////////////////////////////////////////////
121     template <typename Elements, typename Attribute, typename Context
122       , typename Iterator>
123     struct handles_container<qi::sequential_or<Elements>, Attribute, Context
124       , Iterator>
125       : nary_handles_container<Elements, Attribute, Context, Iterator> {};
126 }}}
127 
128 #endif
129