1// Copyright (c) 2001-2011 Hartmut Kaiser
2//
3// Distributed under the Boost Software License, Version 1.0. (See accompanying
4// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5
6#if !defined(SPIRIT_QI_ATTR_CAST_SEP_26_2009_0735PM)
7#define SPIRIT_QI_ATTR_CAST_SEP_26_2009_0735PM
8
9#if defined(_MSC_VER)
10#pragma once
11#endif
12
13#include <boost/spirit/home/qi/meta_compiler.hpp>
14#include <boost/spirit/home/qi/parser.hpp>
15#include <boost/spirit/home/qi/domain.hpp>
16#include <boost/spirit/home/support/unused.hpp>
17#include <boost/spirit/home/support/info.hpp>
18#include <boost/spirit/home/support/common_terminals.hpp>
19#include <boost/spirit/home/qi/detail/attributes.hpp>
20#include <boost/spirit/home/support/auxiliary/attr_cast.hpp>
21
22namespace boost { namespace spirit
23{
24 ///////////////////////////////////////////////////////////////////////////
25 // Enablers
26 ///////////////////////////////////////////////////////////////////////////
27
28 // enables attr_cast<>() pseudo parser
29 template <typename Expr, typename Exposed, typename Transformed>
30 struct use_terminal<qi::domain
31 , tag::stateful_tag<Expr, tag::attr_cast, Exposed, Transformed> >
32 : mpl::true_ {};
33}}
34
35namespace boost { namespace spirit { namespace qi
36{
37 using spirit::attr_cast;
38
39 ///////////////////////////////////////////////////////////////////////////
40 // attr_cast_parser consumes the attribute of subject generator without
41 // generating anything
42 ///////////////////////////////////////////////////////////////////////////
43 template <typename Exposed, typename Transformed, typename Subject>
44 struct attr_cast_parser
45 : unary_parser<attr_cast_parser<Exposed, Transformed, Subject> >
46 {
47 typedef typename result_of::compile<qi::domain, Subject>::type
48 subject_type;
49
50 typedef typename mpl::eval_if<
51 traits::not_is_unused<Transformed>
52 , mpl::identity<Transformed>
53 , traits::attribute_of<subject_type> >::type
54 transformed_attribute_type;
55
56 attr_cast_parser(Subject const& subject_)
57 : subject(subject_)
58 {
59 // If you got an error_invalid_expression error message here,
60 // then the expression (Subject) is not a valid spirit qi
61 // expression.
62 BOOST_SPIRIT_ASSERT_MATCH(qi::domain, Subject);
63 }
64
65 // If Exposed is given, we use the given type, otherwise all we can do
66 // is to guess, so we expose our inner type as an attribute and
67 // deal with the passed attribute inside the parse function.
68 template <typename Context, typename Iterator>
69 struct attribute
70 : mpl::if_<traits::not_is_unused<Exposed>, Exposed
71 , transformed_attribute_type>
72 {};
73
74 template <typename Iterator, typename Context, typename Skipper
75 , typename Attribute>
76 bool parse(Iterator& first, Iterator const& last
77 , Context& context, Skipper const& skipper
78 , Attribute& attr_param) const
79 {
80 // Find the real exposed attribute. If exposed is given, we use it
81 // otherwise we assume the exposed attribute type to be the actual
82 // attribute type as passed by the user.
83 typedef typename mpl::if_<
84 traits::not_is_unused<Exposed>, Exposed, Attribute>::type
85 exposed_attribute_type;
86
87 // do down-stream transformation, provides attribute for embedded
88 // parser
89 typedef traits::transform_attribute<
90 exposed_attribute_type, transformed_attribute_type, domain>
91 transform;
92
93 typename transform::type attr_ = transform::pre(attr_param);
94
95 if (!compile<qi::domain>(subject).
96 parse(first, last, context, skipper, attr_))
97 {
98 transform::fail(attr_param);
99 return false;
100 }
101
102 // do up-stream transformation, this mainly integrates the results
103 // back into the original attribute value, if appropriate
104 traits::post_transform(attr_param, attr_);
105 return true;
106 }
107
108 template <typename Context>
109 info what(Context& context) const
110 {
111 return info("attr_cast"
112 , compile<qi::domain>(subject).what(context));
113 }
114
115 Subject subject;
116
117 private:
118 // silence MSVC warning C4512: assignment operator could not be generated
119 attr_cast_parser& operator= (attr_cast_parser const&);
120 };
121
122 ///////////////////////////////////////////////////////////////////////////
123 // Parser generator: make_xxx function (objects)
124 ///////////////////////////////////////////////////////////////////////////
125 template <typename Expr, typename Exposed, typename Transformed
126 , typename Modifiers>
127 struct make_primitive<
128 tag::stateful_tag<Expr, tag::attr_cast, Exposed, Transformed>, Modifiers>
129 {
130 typedef attr_cast_parser<Exposed, Transformed, Expr> result_type;
131
132 template <typename Terminal>
133 result_type operator()(Terminal const& term, unused_type) const
134 {
135 typedef tag::stateful_tag<
136 Expr, tag::attr_cast, Exposed, Transformed> tag_type;
137 using spirit::detail::get_stateful_data;
138 return result_type(get_stateful_data<tag_type>::call(term));
139 }
140 };
141
142
143}}}
144
145#endif
146

source code of qtlocation/src/3rdparty/mapbox-gl-native/deps/boost/1.65.1/include/boost/spirit/home/qi/auxiliary/attr_cast.hpp