1/*=============================================================================
2 Copyright (c) 2001-2011 Hartmut Kaiser
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_ALTERNATIVE_FUNCTION_APRIL_23_2007_1046AM)
8#define SPIRIT_ALTERNATIVE_FUNCTION_APRIL_23_2007_1046AM
9
10#if defined(_MSC_VER)
11#pragma once
12#endif
13
14#include <boost/spirit/home/qi/domain.hpp>
15#include <boost/spirit/home/qi/detail/assign_to.hpp>
16#include <boost/spirit/home/support/unused.hpp>
17#include <boost/spirit/home/qi/detail/attributes.hpp>
18#include <boost/variant.hpp>
19#include <boost/mpl/bool.hpp>
20
21namespace boost { namespace spirit { namespace qi { namespace detail
22{
23 template <typename Variant, typename Expected>
24 struct find_substitute
25 {
26 // Get the type from the variant that can be a substitute for Expected.
27 // If none is found, just return Expected
28
29 typedef Variant variant_type;
30 typedef typename variant_type::types types;
31 typedef typename mpl::end<types>::type end;
32
33 typedef typename
34 mpl::find_if<types, is_same<mpl::_1, Expected> >::type
35 iter_1;
36
37 typedef typename
38 mpl::eval_if<
39 is_same<iter_1, end>,
40 mpl::find_if<types, traits::is_substitute<mpl::_1, Expected> >,
41 mpl::identity<iter_1>
42 >::type
43 iter;
44
45 typedef typename
46 mpl::eval_if<
47 is_same<iter, end>,
48 mpl::identity<Expected>,
49 mpl::deref<iter>
50 >::type
51 type;
52 };
53
54 template <typename Iterator, typename Context, typename Skipper,
55 typename Attribute>
56 struct alternative_function
57 {
58 alternative_function(
59 Iterator& first_, Iterator const& last_, Context& context_,
60 Skipper const& skipper_, Attribute& attr_)
61 : first(first_), last(last_), context(context_), skipper(skipper_),
62 attr(attr_)
63 {
64 }
65
66 template <typename Component>
67 bool call(Component const& component, mpl::true_) const
68 {
69 // if Attribute is not a variant, then pass it as-is
70 return component.parse(first, last, context, skipper, attr);
71 }
72
73 template <typename Component>
74 bool call_optional_or_variant(Component const& component, mpl::true_) const
75 {
76 // If Attribute is an optional, then create an attribute for the Component
77 // with the type optional::value_type. If the expected attribute is unused type,
78 // use it instead.
79 typedef typename
80 traits::attribute_of<Component, Context, Iterator>::type
81 expected_type;
82
83 typename mpl::if_<
84 is_same<expected_type, unused_type>,
85 unused_type,
86 typename Attribute::value_type>::type
87 val;
88
89 if (component.parse(first, last, context, skipper, val))
90 {
91 traits::assign_to(val, attr);
92 return true;
93 }
94 return false;
95 }
96
97 template <typename Component>
98 bool call_variant(Component const& component, mpl::false_) const
99 {
100 // If Attribute is a variant, then search the variant types for a
101 // suitable substitute type.
102
103 typename
104 find_substitute<Attribute,
105 typename traits::attribute_of<Component, Context, Iterator>::type
106 >::type
107 val;
108
109 if (component.parse(first, last, context, skipper, val))
110 {
111 traits::assign_to(val, attr);
112 return true;
113 }
114 return false;
115 }
116
117 template <typename Component>
118 bool call_variant(Component const& component, mpl::true_) const
119 {
120 // If Attribute is a variant and the expected attribute is
121 // the same type (pass the variant as-is).
122
123 return component.parse(first, last, context, skipper, attr);
124 }
125
126 template <typename Component>
127 bool call_optional_or_variant(Component const& component, mpl::false_) const
128 {
129 // Attribute is a variant...
130
131 typedef typename
132 traits::attribute_of<Component, Context, Iterator>::type
133 expected;
134 return call_variant(component,
135 is_same<Attribute, expected>());
136 }
137
138 template <typename Component>
139 bool call(Component const& component, mpl::false_) const
140 {
141 // fix for alternative.cpp test case, FHE 2016-07-28
142 return call_optional_or_variant(
143 component, mpl::not_<spirit::traits::not_is_optional<Attribute, qi::domain> >());
144 }
145
146 template <typename Component>
147 bool call_unused(Component const& component, mpl::true_) const
148 {
149 // return true if the parser succeeds
150 return call(component,
151 mpl::and_<
152 spirit::traits::not_is_variant<Attribute, qi::domain>,
153 spirit::traits::not_is_optional<Attribute, qi::domain>
154 >());
155 }
156
157 template <typename Component>
158 bool call_unused(Component const& component, mpl::false_) const
159 {
160 return component.parse(first, last, context, skipper, unused);
161 }
162
163 template <typename Component>
164 bool operator()(Component const& component) const
165 {
166 // return true if the parser succeeds
167 typedef typename traits::not_is_unused<
168 typename traits::attribute_of<Component, Context, Iterator>::type
169 >::type predicate;
170
171 return call_unused(component, predicate());
172 }
173
174 Iterator& first;
175 Iterator const& last;
176 Context& context;
177 Skipper const& skipper;
178 Attribute& attr;
179
180 private:
181 // silence MSVC warning C4512: assignment operator could not be generated
182 alternative_function& operator= (alternative_function const&);
183 };
184
185 template <typename Iterator, typename Context, typename Skipper>
186 struct alternative_function<Iterator, Context, Skipper, unused_type const>
187 {
188 alternative_function(
189 Iterator& first_, Iterator const& last_, Context& context_,
190 Skipper const& skipper_, unused_type)
191 : first(first_), last(last_), context(context_), skipper(skipper_)
192 {
193 }
194
195 template <typename Component>
196 bool operator()(Component const& component) const
197 {
198 // return true if the parser succeeds
199 return component.parse(first, last, context, skipper,
200 unused);
201 }
202
203 Iterator& first;
204 Iterator const& last;
205 Context& context;
206 Skipper const& skipper;
207
208 private:
209 // silence MSVC warning C4512: assignment operator could not be generated
210 alternative_function& operator= (alternative_function const&);
211 };
212
213}}}}
214
215#endif
216

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