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_DIRECTIVE_SKIP_HPP
8#define BOOST_SPIRIT_QI_DIRECTIVE_SKIP_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/parser.hpp>
16#include <boost/spirit/home/qi/auxiliary/lazy.hpp>
17#include <boost/spirit/home/qi/operator/kleene.hpp>
18#include <boost/spirit/home/qi/directive/lexeme.hpp>
19#include <boost/spirit/home/qi/skip_over.hpp>
20#include <boost/spirit/home/qi/detail/unused_skipper.hpp>
21#include <boost/spirit/home/support/container.hpp>
22#include <boost/spirit/home/support/common_terminals.hpp>
23#include <boost/spirit/home/qi/detail/attributes.hpp>
24#include <boost/spirit/home/support/info.hpp>
25#include <boost/spirit/home/support/has_semantic_action.hpp>
26#include <boost/spirit/home/support/handles_container.hpp>
27#include <boost/fusion/include/at.hpp>
28#include <boost/fusion/include/vector.hpp>
29#include <boost/utility/enable_if.hpp>
30
31namespace boost { namespace spirit
32{
33 ///////////////////////////////////////////////////////////////////////////
34 // Enablers
35 ///////////////////////////////////////////////////////////////////////////
36 template <>
37 struct use_directive<qi::domain, tag::skip> // enables skip[p]
38 : mpl::true_ {};
39
40 template <typename T>
41 struct use_directive<qi::domain
42 , terminal_ex<tag::skip // enables skip(s)[p]
43 , fusion::vector1<T> >
44 > : boost::spirit::traits::matches<qi::domain, T> {};
45
46 template <> // enables *lazy* skip(s)[p]
47 struct use_lazy_directive<
48 qi::domain
49 , tag::skip
50 , 1 // arity
51 > : mpl::true_ {};
52}}
53
54namespace boost { namespace spirit { namespace qi
55{
56#ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
57 using spirit::skip;
58#endif
59 using spirit::skip_type;
60
61 template <typename Subject>
62 struct reskip_parser : unary_parser<reskip_parser<Subject> >
63 {
64 typedef Subject subject_type;
65
66 template <typename Context, typename Iterator>
67 struct attribute
68 {
69 typedef typename
70 traits::attribute_of<Subject, Context, Iterator>::type
71 type;
72 };
73
74 reskip_parser(Subject const& subject_)
75 : subject(subject_) {}
76
77 template <typename Iterator, typename Context
78 , typename Skipper, typename Attribute>
79 typename enable_if<detail::is_unused_skipper<Skipper>, bool>::type
80 parse(Iterator& first, Iterator const& last
81 , Context& context, Skipper const& u // --> The skipper is reintroduced
82 , Attribute& attr_) const
83 {
84 return subject.parse(first, last, context
85 , detail::get_skipper(u), attr_);
86 }
87 template <typename Iterator, typename Context
88 , typename Skipper, typename Attribute>
89 typename disable_if<detail::is_unused_skipper<Skipper>, bool>::type
90 parse(Iterator& first, Iterator const& last
91 , Context& context, Skipper const& skipper
92 , Attribute& attr_) const
93 {
94 return subject.parse(first, last, context
95 , skipper, attr_);
96 }
97
98 template <typename Context>
99 info what(Context& context) const
100 {
101 return info("skip", subject.what(context));
102 }
103
104 Subject subject;
105 };
106
107 template <typename Subject, typename Skipper>
108 struct skip_parser : unary_parser<skip_parser<Subject, Skipper> >
109 {
110 typedef Subject subject_type;
111 typedef Skipper skipper_type;
112
113 template <typename Context, typename Iterator>
114 struct attribute
115 {
116 typedef typename
117 traits::attribute_of<Subject, Context, Iterator>::type
118 type;
119 };
120
121 skip_parser(Subject const& subject_, Skipper const& skipper_)
122 : subject(subject_), skipper(skipper_) {}
123
124 template <typename Iterator, typename Context
125 , typename Skipper_, typename Attribute>
126 bool parse(Iterator& first, Iterator const& last
127 , Context& context, Skipper_ const& //skipper --> bypass the supplied skipper
128 , Attribute& attr_) const
129 {
130 return subject.parse(first, last, context, skipper, attr_);
131 }
132
133 template <typename Context>
134 info what(Context& context) const
135 {
136 return info("skip", subject.what(context));
137 }
138
139 Subject subject;
140 Skipper skipper;
141 };
142
143 ///////////////////////////////////////////////////////////////////////////
144 // Parser generators: make_xxx function (objects)
145 ///////////////////////////////////////////////////////////////////////////
146 template <typename Subject, typename Modifiers>
147 struct make_directive<tag::skip, Subject, Modifiers>
148 {
149 typedef reskip_parser<Subject> result_type;
150 result_type operator()(unused_type, Subject const& subject, unused_type) const
151 {
152 return result_type(subject);
153 }
154 };
155
156 template <typename Skipper, typename Subject, typename Modifiers>
157 struct make_directive<
158 terminal_ex<tag::skip, fusion::vector1<Skipper> >, Subject, Modifiers>
159 {
160 typedef typename
161 result_of::compile<qi::domain, Skipper, Modifiers>::type
162 skipper_type;
163
164 typedef skip_parser<Subject, skipper_type> result_type;
165
166 template <typename Terminal>
167 result_type operator()(Terminal const& term, Subject const& subject
168 , Modifiers const& modifiers) const
169 {
170 return result_type(subject
171 , compile<qi::domain>(fusion::at_c<0>(term.args), modifiers));
172 }
173 };
174
175}}}
176
177namespace boost { namespace spirit { namespace traits
178{
179 ///////////////////////////////////////////////////////////////////////////
180 template <typename Subject>
181 struct has_semantic_action<qi::reskip_parser<Subject> >
182 : unary_has_semantic_action<Subject> {};
183
184 template <typename Subject, typename Skipper>
185 struct has_semantic_action<qi::skip_parser<Subject, Skipper> >
186 : unary_has_semantic_action<Subject> {};
187
188 ///////////////////////////////////////////////////////////////////////////
189 template <typename Subject, typename Attribute, typename Context
190 , typename Iterator>
191 struct handles_container<qi::reskip_parser<Subject>, Attribute
192 , Context, Iterator>
193 : unary_handles_container<Subject, Attribute, Context, Iterator> {};
194
195 template <typename Subject, typename Skipper, typename Attribute
196 , typename Context, typename Iterator>
197 struct handles_container<qi::skip_parser<Subject, Skipper>, Attribute
198 , Context, Iterator>
199 : unary_handles_container<Subject, Attribute, Context, Iterator> {};
200}}}
201
202#endif
203

source code of boost/libs/spirit/include/boost/spirit/home/qi/directive/skip.hpp