ceph/src/boost/boost/spirit/home/x3/nonterminal/detail/rule.hpp

   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_DETAIL_RULE_JAN_08_2012_0326PM)
   8 #define BOOST_SPIRIT_X3_DETAIL_RULE_JAN_08_2012_0326PM
   9
  10 #include <boost/core/ignore_unused.hpp>
  11 #include <boost/spirit/home/x3/auxiliary/guard.hpp>
  12 #include <boost/spirit/home/x3/core/parser.hpp>
  13 #include <boost/spirit/home/x3/core/skip_over.hpp>
  14 #include <boost/spirit/home/x3/directive/expect.hpp>
  15 #include <boost/spirit/home/x3/support/traits/make_attribute.hpp>
  16 #include <boost/spirit/home/x3/support/utility/sfinae.hpp>
  17 #include <boost/spirit/home/x3/nonterminal/detail/transform_attribute.hpp>
  18 #include <boost/utility/addressof.hpp>
  19
  20 #if defined(BOOST_SPIRIT_X3_DEBUG)
  21 #include <boost/spirit/home/x3/nonterminal/simple_trace.hpp>
  22 #endif
  23
  24 namespace boost { namespace spirit { namespace x3
  25 {
  26     template <typename ID>
  27     struct identity;
  28
  29     template <typename ID, typename Attribute = unused_type, bool force_attribute = false>
  30     struct rule;
  31
  32     struct parse_pass_context_tag;
  33
  34     namespace detail
  35     {
  36         // we use this so we can detect if the default parse_rule
  37         // is the being called.
  38         struct default_parse_rule_result
  39         {
  40             default_parse_rule_result(bool r)
  41               : r(r) {}
  42             operator bool() const { return r; }
  43             bool r;
  44         };
  45     }
  46
  47     // default parse_rule implementation
  48     template <typename ID, typename Attribute, typename Iterator
  49       , typename Context, typename ActualAttribute>
  50     inline detail::default_parse_rule_result
  51     parse_rule(
  52         rule<ID, Attribute> rule_
  53       , Iterator& first, Iterator const& last
  54       , Context const& context, ActualAttribute& attr);
  55 }}}
  56
  57 namespace boost { namespace spirit { namespace x3 { namespace detail
  58 {
  59 #if defined(BOOST_SPIRIT_X3_DEBUG)
  60     template <typename Iterator, typename Attribute>
  61     struct context_debug
  62     {
  63         context_debug(
  64             char const* rule_name
  65           , Iterator const& first, Iterator const& last
  66           , Attribute const& attr
  67           , bool const& ok_parse //was parse successful?
  68           )
  69           : ok_parse(ok_parse), rule_name(rule_name)
  70           , first(first), last(last)
  71           , attr(attr)
  72           , f(detail::get_simple_trace())
  73         {
  74             f(first, last, attr, pre_parse, rule_name);
  75         }
  76
  77         ~context_debug()
  78         {
  79             auto status = ok_parse ? successful_parse : failed_parse ;
  80             f(first, last, attr, status, rule_name);
  81         }
  82
  83         bool const& ok_parse;
  84         char const* rule_name;
  85         Iterator const& first;
  86         Iterator const& last;
  87         Attribute const& attr;
  88         detail::simple_trace_type& f;
  89     };
  90 #endif
  91
  92     template <typename ID, typename Iterator, typename Context, typename Enable = void>
  93     struct has_on_error : mpl::false_ {};
  94
  95     template <typename ID, typename Iterator, typename Context>
  96     struct has_on_error<ID, Iterator, Context,
  97         typename disable_if_substitution_failure<
  98             decltype(
  99                 std::declval<ID>().on_error(
 100                     std::declval<Iterator&>()
 101                   , std::declval<Iterator>()
 102                   , std::declval<expectation_failure<Iterator>>()
 103                   , std::declval<Context>()
 104                 )
 105             )>::type
 106         >
 107       : mpl::true_
 108     {};
 109
 110     template <typename ID, typename Iterator, typename Attribute, typename Context, typename Enable = void>
 111     struct has_on_success : mpl::false_ {};
 112
 113     template <typename ID, typename Iterator, typename Attribute, typename Context>
 114     struct has_on_success<ID, Iterator, Context, Attribute,
 115         typename disable_if_substitution_failure<
 116             decltype(
 117                 std::declval<ID>().on_success(
 118                     std::declval<Iterator&>()
 119                   , std::declval<Iterator>()
 120                   , std::declval<Attribute&>()
 121                   , std::declval<Context>()
 122                 )
 123             )>::type
 124         >
 125       : mpl::true_
 126     {};
 127
 128     template <typename ID>
 129     struct make_id
 130     {
 131         typedef identity<ID> type;
 132     };
 133
 134     template <typename ID>
 135     struct make_id<identity<ID>>
 136     {
 137         typedef identity<ID> type;
 138     };
 139
 140     template <typename ID, typename RHS, typename Context>
 141     Context const&
 142     make_rule_context(RHS const& /* rhs */, Context const& context
 143       , mpl::false_ /* is_default_parse_rule */)
 144     {
 145         return context;
 146     }
 147
 148     template <typename ID, typename RHS, typename Context>
 149     auto make_rule_context(RHS const& rhs, Context const& context
 150       , mpl::true_ /* is_default_parse_rule */ )
 151     {
 152         return make_unique_context<ID>(rhs, context);
 153     }
 154
 155     template <typename Attribute, typename ID>
 156     struct rule_parser
 157     {
 158         template <typename Iterator, typename Context, typename ActualAttribute>
 159         static bool call_on_success(
 160             Iterator& /* first */, Iterator const& /* last */
 161           , Context const& /* context */, ActualAttribute& /* attr */
 162           , mpl::false_ /* No on_success handler */ )
 163         {
 164             return true;
 165         }
 166
 167         template <typename Iterator, typename Context, typename ActualAttribute>
 168         static bool call_on_success(
 169             Iterator& first, Iterator const& last
 170           , Context const& context, ActualAttribute& attr
 171           , mpl::true_ /* Has on_success handler */)
 172         {
 173             bool pass = true;
 174             ID().on_success(
 175                 first
 176               , last
 177               , attr
 178               , make_context<parse_pass_context_tag>(pass, context)
 179             );
 180             return pass;
 181         }
 182
 183         template <typename RHS, typename Iterator, typename Context
 184           , typename RContext, typename ActualAttribute>
 185         static bool parse_rhs_main(
 186             RHS const& rhs
 187           , Iterator& first, Iterator const& last
 188           , Context const& context, RContext& rcontext, ActualAttribute& attr
 189           , mpl::false_)
 190         {
 191             // see if the user has a BOOST_SPIRIT_DEFINE for this rule
 192             typedef
 193                 decltype(parse_rule(
 194                     rule<ID, Attribute>(), first, last
 195                   , make_unique_context<ID>(rhs, context), attr))
 196             parse_rule_result;
 197
 198             // If there is no BOOST_SPIRIT_DEFINE for this rule,
 199             // we'll make a context for this rule tagged by its ID
 200             // so we can extract the rule later on in the default
 201             // (generic) parse_rule function.
 202             typedef
 203                 is_same<parse_rule_result, default_parse_rule_result>
 204             is_default_parse_rule;
 205
 206             Iterator i = first;
 207             bool r = rhs.parse(
 208                 i
 209               , last
 210               , make_rule_context<ID>(rhs, context, is_default_parse_rule())
 211               , rcontext
 212               , attr
 213             );
 214
 215             if (r)
 216             {
 217                 auto first_ = first;
 218                 x3::skip_over(first_, last, context);
 219                 r = call_on_success(first_, i, context, attr
 220                   , has_on_success<ID, Iterator, Context, ActualAttribute>());
 221             }
 222
 223             if (r)
 224                 first = i;
 225             return r;
 226         }
 227
 228         template <typename RHS, typename Iterator, typename Context
 229           , typename RContext, typename ActualAttribute>
 230         static bool parse_rhs_main(
 231             RHS const& rhs
 232           , Iterator& first, Iterator const& last
 233           , Context const& context, RContext& rcontext, ActualAttribute& attr
 234           , mpl::true_ /* on_error is found */)
 235         {
 236             for (;;)
 237             {
 238                 try
 239                 {
 240                     return parse_rhs_main(
 241                         rhs, first, last, context, rcontext, attr, mpl::false_());
 242                 }
 243                 catch (expectation_failure<Iterator> const& x)
 244                 {
 245                     switch (ID().on_error(first, last, x, context))
 246                     {
 247                         case error_handler_result::fail:
 248                             return false;
 249                         case error_handler_result::retry:
 250                             continue;
 251                         case error_handler_result::accept:
 252                             return true;
 253                         case error_handler_result::rethrow:
 254                             throw;
 255                     }
 256                 }
 257             }
 258         }
 259
 260         template <typename RHS, typename Iterator
 261           , typename Context, typename RContext, typename ActualAttribute>
 262         static bool parse_rhs_main(
 263             RHS const& rhs
 264           , Iterator& first, Iterator const& last
 265           , Context const& context, RContext& rcontext, ActualAttribute& attr)
 266         {
 267             return parse_rhs_main(
 268                 rhs, first, last, context, rcontext, attr
 269               , has_on_error<ID, Iterator, Context>()
 270             );
 271         }
 272
 273         template <typename RHS, typename Iterator
 274           , typename Context, typename RContext, typename ActualAttribute>
 275         static bool parse_rhs(
 276             RHS const& rhs
 277           , Iterator& first, Iterator const& last
 278           , Context const& context, RContext& rcontext, ActualAttribute& attr
 279           , mpl::false_)
 280         {
 281             return parse_rhs_main(rhs, first, last, context, rcontext, attr);
 282         }
 283
 284         template <typename RHS, typename Iterator
 285           , typename Context, typename RContext, typename ActualAttribute>
 286         static bool parse_rhs(
 287             RHS const& rhs
 288           , Iterator& first, Iterator const& last
 289           , Context const& context, RContext& rcontext, ActualAttribute& /* attr */
 290           , mpl::true_)
 291         {
 292             return parse_rhs_main(rhs, first, last, context, rcontext, unused);
 293         }
 294
 295         template <typename RHS, typename Iterator, typename Context
 296           , typename ActualAttribute, typename ExplicitAttrPropagation>
 297         static bool call_rule_definition(
 298             RHS const& rhs
 299           , char const* rule_name
 300           , Iterator& first, Iterator const& last
 301           , Context const& context, ActualAttribute& attr
 302           , ExplicitAttrPropagation)
 303         {
 304             boost::ignore_unused(rule_name);
 305
 306             typedef traits::make_attribute<Attribute, ActualAttribute> make_attribute;
 307
 308             // do down-stream transformation, provides attribute for
 309             // rhs parser
 310             typedef traits::transform_attribute<
 311                 typename make_attribute::type, Attribute, parser_id>
 312             transform;
 313
 314             typedef typename make_attribute::value_type value_type;
 315             typedef typename transform::type transform_attr;
 316             value_type made_attr = make_attribute::call(attr);
 317             transform_attr attr_ = transform::pre(made_attr);
 318
 319             bool ok_parse
 320               //Creates a place to hold the result of parse_rhs
 321               //called inside the following scope.
 322               ;
 323             {
 324              // Create a scope to cause the dbg variable below (within
 325              // the #if...#endif) to call it's DTOR before any
 326              // modifications are made to the attribute, attr_ passed
 327              // to parse_rhs (such as might be done in
 328              // traits::post_transform when, for example,
 329              // ActualAttribute is a recursive variant).
 330 #if defined(BOOST_SPIRIT_X3_DEBUG)
 331                 context_debug<Iterator, transform_attr>
 332                 dbg(rule_name, first, last, attr_, ok_parse);
 333 #endif
 334                 ok_parse = parse_rhs(rhs, first, last, context, attr_, attr_
 335                    , mpl::bool_
 336                      < (  RHS::has_action
 337                        && !ExplicitAttrPropagation::value
 338                        )
 339                      >()
 340                   );
 341             }
 342             if (ok_parse)
 343             {
 344                 // do up-stream transformation, this integrates the results
 345                 // back into the original attribute value, if appropriate
 346                 traits::post_transform(attr, std::forward<transform_attr>(attr_));
 347             }
 348             return ok_parse;
 349         }
 350     };
 351 }}}}
 352
 353 #endif