1/*=============================================================================
2 Copyright (c) 2001-2014 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(BOOST_SPIRIT_X3_SKIP_APRIL_16_2006_0625PM)
8#define BOOST_SPIRIT_X3_SKIP_APRIL_16_2006_0625PM
9
10#include <boost/spirit/home/x3/support/unused.hpp>
11#include <boost/spirit/home/x3/support/context.hpp>
12#include <boost/spirit/home/x3/support/traits/attribute_category.hpp>
13#include <boost/mpl/bool.hpp>
14#include <boost/mpl/not.hpp>
15#include <boost/type_traits/remove_cv.hpp>
16#include <boost/type_traits/remove_reference.hpp>
17#include <boost/utility/declval.hpp>
18
19namespace boost { namespace spirit { namespace x3
20{
21 ///////////////////////////////////////////////////////////////////////////
22 // Move the /first/ iterator to the first non-matching position
23 // given a skip-parser. The function is a no-op if unused_type or
24 // unused_skipper is passed as the skip-parser.
25 ///////////////////////////////////////////////////////////////////////////
26 template <typename Skipper>
27 struct unused_skipper : unused_type
28 {
29 unused_skipper(Skipper const& skipper)
30 : skipper(skipper) {}
31 Skipper const& skipper;
32 };
33
34 namespace detail
35 {
36 template <typename Skipper>
37 struct is_unused_skipper
38 : mpl::false_ {};
39
40 template <typename Skipper>
41 struct is_unused_skipper<unused_skipper<Skipper>>
42 : mpl::true_ {};
43
44 template <>
45 struct is_unused_skipper<unused_type>
46 : mpl::true_ {};
47
48 template <typename Skipper>
49 inline Skipper const&
50 get_unused_skipper(Skipper const& skipper)
51 {
52 return skipper;
53 }
54 template <typename Skipper>
55 inline Skipper const&
56 get_unused_skipper(unused_skipper<Skipper> const& unused_skipper)
57 {
58 return unused_skipper.skipper;
59 }
60
61 template <typename Iterator, typename Skipper>
62 inline void skip_over(
63 Iterator& first, Iterator const& last, Skipper const& skipper)
64 {
65 while (skipper.parse(first, last, unused, unused, unused))
66 /***/;
67 }
68
69 template <typename Iterator>
70 inline void skip_over(Iterator&, Iterator const&, unused_type)
71 {
72 }
73
74 template <typename Iterator, typename Skipper>
75 inline void skip_over(
76 Iterator&, Iterator const&, unused_skipper<Skipper> const&)
77 {
78 }
79 }
80
81 // this tag is used to find the skipper from the context
82 struct skipper_tag;
83
84 template <typename Context>
85 struct has_skipper
86 : mpl::not_<detail::is_unused_skipper<
87 typename remove_cv<typename remove_reference<
88 decltype(x3::get<skipper_tag>(boost::declval<Context>()))
89 >::type>::type
90 >> {};
91
92 template <typename Iterator, typename Context>
93 inline void skip_over(
94 Iterator& first, Iterator const& last, Context const& context)
95 {
96 detail::skip_over(first, last, x3::get<skipper_tag>(context));
97 }
98}}}
99
100#endif
101

source code of boost/libs/spirit/include/boost/spirit/home/x3/core/skip_over.hpp