/Src/Dependencies/Boost/boost/spirit/home/qi/detail/pass_container.hpp
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1/*============================================================================= 2 Copyright (c) 2001-2011 Joel de Guzman 3 Copyright (c) 2001-2011 Hartmut Kaiser 4 5 Distributed under the Boost Software License, Version 1.0. (See accompanying 6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 7=============================================================================*/ 8#if !defined(SPIRIT_PASS_CONTAINER_JANUARY_06_2009_0802PM) 9#define SPIRIT_PASS_CONTAINER_JANUARY_06_2009_0802PM 10 11#if defined(_MSC_VER) 12#pragma once 13#endif 14 15#include <boost/spirit/home/qi/detail/attributes.hpp> 16#include <boost/spirit/home/support/container.hpp> 17#include <boost/spirit/home/support/handles_container.hpp> 18#include <boost/type_traits/is_base_of.hpp> 19#include <boost/type_traits/is_convertible.hpp> 20#include <boost/mpl/bool.hpp> 21#include <boost/mpl/and.hpp> 22#include <boost/mpl/or.hpp> 23#include <boost/preprocessor/cat.hpp> 24#include <boost/preprocessor/repetition/repeat.hpp> 25 26namespace boost { namespace spirit { namespace qi { namespace detail 27{ 28 // Helper meta-function allowing to evaluate weak substitutability and 29 // negate the result if the predicate (Sequence) is not true 30 template <typename Sequence, typename Attribute, typename ValueType> 31 struct negate_weak_substitute_if_not 32 : mpl::if_< 33 Sequence 34 , typename traits::is_weak_substitute<Attribute, ValueType>::type 35 , typename mpl::not_< 36 traits::is_weak_substitute<Attribute, ValueType> 37 >::type> 38 {}; 39 40 // pass_through_container: utility to check decide whether a provided 41 // container attribute needs to be passed through to the current component 42 // or of we need to split the container by passing along instances of its 43 // value type 44 45 // if the expected attribute of the current component is neither a Fusion 46 // sequence nor a container, we will pass through the provided container 47 // only if its value type is not compatible with the component 48 template <typename Container, typename ValueType, typename Attribute 49 , typename Sequence, typename Enable = void> 50 struct pass_through_container_base 51 : negate_weak_substitute_if_not<Sequence, Attribute, ValueType> 52 {}; 53 54 // Specialization for fusion sequences, in this case we check whether all 55 // the types in the sequence are convertible to the lhs attribute. 56 // 57 // We return false if the rhs attribute itself is a fusion sequence, which 58 // is compatible with the LHS sequence (we want to pass through this 59 // attribute without it being split apart). 60 template <typename Container, typename ValueType, typename Attribute 61 , typename Sequence = mpl::true_> 62 struct not_compatible_element 63 : mpl::and_< 64 negate_weak_substitute_if_not<Sequence, Attribute, Container> 65 , negate_weak_substitute_if_not<Sequence, Attribute, ValueType> > 66 {}; 67 68 // If the value type of the container is not a Fusion sequence, we pass 69 // through the container if each of the elements of the Attribute 70 // sequence is compatible with either the container or its value type. 71 template <typename Container, typename ValueType, typename Attribute 72 , typename Sequence 73 , bool IsSequence = fusion::traits::is_sequence<ValueType>::value> 74 struct pass_through_container_fusion_sequence 75 { 76 typedef typename mpl::find_if< 77 Attribute, not_compatible_element<Container, ValueType, mpl::_1> 78 >::type iter; 79 typedef typename mpl::end<Attribute>::type end; 80 81 typedef typename is_same<iter, end>::type type; 82 }; 83 84 // If both, the Attribute and the value type of the provided container 85 // are Fusion sequences, we pass the container only if the two 86 // sequences are not compatible. 87 template <typename Container, typename ValueType, typename Attribute 88 , typename Sequence> 89 struct pass_through_container_fusion_sequence< 90 Container, ValueType, Attribute, Sequence, true> 91 { 92 typedef typename mpl::find_if< 93 Attribute 94 , not_compatible_element<Container, ValueType, mpl::_1, Sequence> 95 >::type iter; 96 typedef typename mpl::end<Attribute>::type end; 97 98 typedef typename is_same<iter, end>::type type; 99 }; 100 101 template <typename Container, typename ValueType, typename Attribute 102 , typename Sequence> 103 struct pass_through_container_base<Container, ValueType, Attribute 104 , Sequence 105 , typename enable_if<fusion::traits::is_sequence<Attribute> >::type> 106 : pass_through_container_fusion_sequence< 107 Container, ValueType, Attribute, Sequence> 108 {}; 109 110 // Specialization for containers 111 // 112 // If the value type of the attribute of the current component is not 113 // a Fusion sequence, we have to pass through the provided container if 114 // both are compatible. 115 template <typename Container, typename ValueType, typename Attribute 116 , typename Sequence, typename AttributeValueType 117 , bool IsSequence = fusion::traits::is_sequence<AttributeValueType>::value> 118 struct pass_through_container_container 119 : mpl::or_< 120 traits::is_weak_substitute<Attribute, Container> 121 , traits::is_weak_substitute<AttributeValueType, Container> > 122 {}; 123 124 // If the value type of the exposed container attribute is a Fusion 125 // sequence, we use the already existing logic for those. 126 template <typename Container, typename ValueType, typename Attribute 127 , typename Sequence, typename AttributeValueType> 128 struct pass_through_container_container< 129 Container, ValueType, Attribute, Sequence, AttributeValueType, true> 130 : pass_through_container_fusion_sequence< 131 Container, ValueType, AttributeValueType, Sequence> 132 {}; 133 134 template <typename Container, typename ValueType, typename Attribute 135 , typename Sequence> 136 struct pass_through_container_base< 137 Container, ValueType, Attribute, Sequence 138 , typename enable_if<traits::is_container<Attribute> >::type> 139 : detail::pass_through_container_container< 140 Container, ValueType, Attribute, Sequence 141 , typename traits::container_value<Attribute>::type> 142 {}; 143 144 // Specialization for exposed optional attributes 145 // 146 // If the type embedded in the exposed optional is not a Fusion 147 // sequence we pass through the container attribute if it is compatible 148 // either to the optionals embedded type or to the containers value 149 // type. 150 template <typename Container, typename ValueType, typename Attribute 151 , typename Sequence 152 , bool IsSequence = fusion::traits::is_sequence<Attribute>::value> 153 struct pass_through_container_optional 154 : mpl::or_< 155 traits::is_weak_substitute<Attribute, Container> 156 , traits::is_weak_substitute<Attribute, ValueType> > 157 {}; 158 159 // If the embedded type of the exposed optional attribute is a Fusion 160 // sequence, we use the already existing logic for those. 161 template <typename Container, typename ValueType, typename Attribute 162 , typename Sequence> 163 struct pass_through_container_optional< 164 Container, ValueType, Attribute, Sequence, true> 165 : pass_through_container_fusion_sequence< 166 Container, ValueType, Attribute, Sequence> 167 {}; 168 169 /////////////////////////////////////////////////////////////////////////// 170 template <typename Container, typename ValueType, typename Attribute 171 , typename Sequence> 172 struct pass_through_container 173 : pass_through_container_base<Container, ValueType, Attribute, Sequence> 174 {}; 175 176 // Handle optional attributes 177 template <typename Container, typename ValueType, typename Attribute 178 , typename Sequence> 179 struct pass_through_container< 180 Container, ValueType, boost::optional<Attribute>, Sequence> 181 : pass_through_container_optional< 182 Container, ValueType, Attribute, Sequence> 183 {}; 184 185 // If both, the containers value type and the exposed attribute type are 186 // optionals we are allowed to pass through the the container only if the 187 // embedded types of those optionals are not compatible. 188 template <typename Container, typename ValueType, typename Attribute 189 , typename Sequence> 190 struct pass_through_container< 191 Container, boost::optional<ValueType>, boost::optional<Attribute> 192 , Sequence> 193 : mpl::not_<traits::is_weak_substitute<Attribute, ValueType> > 194 {}; 195 196 // Specialization for exposed variant attributes 197 // 198 // We pass through the container attribute if at least one of the embedded 199 // types in the variant requires to pass through the attribute 200 201#define BOOST_SPIRIT_PASS_THROUGH_CONTAINER(z, N, _) \ 202 pass_through_container<Container, ValueType, \ 203 BOOST_PP_CAT(T, N), Sequence>::type::value || \ 204 /***/ 205 206 // make sure unused variant parameters do not affect the outcome 207 template <typename Container, typename ValueType, typename Sequence> 208 struct pass_through_container<Container, ValueType 209 , boost::detail::variant::void_, Sequence> 210 : mpl::false_ 211 {}; 212 213 template <typename Container, typename ValueType, typename Sequence 214 , BOOST_VARIANT_ENUM_PARAMS(typename T)> 215 struct pass_through_container<Container, ValueType 216 , boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Sequence> 217 : mpl::bool_<BOOST_PP_REPEAT(BOOST_VARIANT_LIMIT_TYPES 218 , BOOST_SPIRIT_PASS_THROUGH_CONTAINER, _) false> 219 {}; 220 221#undef BOOST_SPIRIT_PASS_THROUGH_CONTAINER 222}}}} 223 224/////////////////////////////////////////////////////////////////////////////// 225namespace boost { namespace spirit { namespace traits 226{ 227 /////////////////////////////////////////////////////////////////////////// 228 // forwarding customization point for domain qi::domain 229 template <typename Container, typename ValueType, typename Attribute 230 , typename Sequence> 231 struct pass_through_container< 232 Container, ValueType, Attribute, Sequence, qi::domain> 233 : qi::detail::pass_through_container< 234 Container, ValueType, Attribute, Sequence> 235 {}; 236}}} 237 238namespace boost { namespace spirit { namespace qi { namespace detail 239{ 240 /////////////////////////////////////////////////////////////////////////// 241 // This function handles the case where the attribute (Attr) given 242 // the sequence is an STL container. This is a wrapper around F. 243 // The function F does the actual parsing. 244 template <typename F, typename Attr, typename Sequence> 245 struct pass_container 246 { 247 typedef typename F::context_type context_type; 248 typedef typename F::iterator_type iterator_type; 249 250 pass_container(F const& f, Attr& attr) 251 : f(f), attr(attr) {} 252 253 // this is for the case when the current element exposes an attribute 254 // which is pushed back onto the container 255 template <typename Component> 256 bool dispatch_container(Component const& component, mpl::false_) const 257 { 258 // synthesized attribute needs to be default constructed 259 typename traits::container_value<Attr>::type val = 260 typename traits::container_value<Attr>::type(); 261 262 iterator_type save = f.first; 263 bool r = f(component, val); 264 if (!r) 265 { 266 // push the parsed value into our attribute 267 r = !traits::push_back(attr, val); 268 if (r) 269 f.first = save; 270 } 271 return r; 272 } 273 274 // this is for the case when the current element is able to handle an 275 // attribute which is a container itself, this element will push its 276 // data directly into the attribute container 277 template <typename Component> 278 bool dispatch_container(Component const& component, mpl::true_) const 279 { 280 return f(component, attr); 281 } 282 283 /////////////////////////////////////////////////////////////////////// 284 // this is for the case when the current element doesn't expect an 285 // attribute 286 template <typename Component> 287 bool dispatch_attribute(Component const& component, mpl::false_) const 288 { 289 return f(component, unused); 290 } 291 292 // the current element expects an attribute 293 template <typename Component> 294 bool dispatch_attribute(Component const& component, mpl::true_) const 295 { 296 typedef typename traits::container_value<Attr>::type value_type; 297 typedef typename traits::attribute_of< 298 Component, context_type, iterator_type>::type 299 rhs_attribute; 300 301 // this predicate detects, whether the attribute of the current 302 // element is a substitute for the value type of the container 303 // attribute 304 typedef mpl::and_< 305 traits::handles_container< 306 Component, Attr, context_type, iterator_type> 307 , traits::pass_through_container< 308 Attr, value_type, rhs_attribute, Sequence, qi::domain> 309 > predicate; 310 311 return dispatch_container(component, predicate()); 312 } 313 314 // Dispatches to dispatch_main depending on the attribute type 315 // of the Component 316 template <typename Component> 317 bool operator()(Component const& component) const 318 { 319 // we need to dispatch depending on the type of the attribute 320 // of the current element (component). If this is has no attribute 321 // we shouldn't pass an attribute at all. 322 typedef typename traits::not_is_unused< 323 typename traits::attribute_of< 324 Component, context_type, iterator_type 325 >::type 326 >::type predicate; 327 328 // ensure the attribute is actually a container type 329 traits::make_container(attr); 330 331 return dispatch_attribute(component, predicate()); 332 } 333 334 F f; 335 Attr& attr; 336 337 private: 338 // silence MSVC warning C4512: assignment operator could not be generated 339 pass_container& operator= (pass_container const&); 340 }; 341 342 /////////////////////////////////////////////////////////////////////////// 343 // Utility function to make a pass_container for container components 344 // (kleene, list, plus, repeat) 345 template <typename F, typename Attr> 346 inline pass_container<F, Attr, mpl::false_> 347 make_pass_container(F const& f, Attr& attr) 348 { 349 return pass_container<F, Attr, mpl::false_>(f, attr); 350 } 351 352 // Utility function to make a pass_container for sequences 353 template <typename F, typename Attr> 354 inline pass_container<F, Attr, mpl::true_> 355 make_sequence_pass_container(F const& f, Attr& attr) 356 { 357 return pass_container<F, Attr, mpl::true_>(f, attr); 358 } 359}}}} 360 361#endif 362