Chris@102: /*=============================================================================
Chris@102:     Copyright (c) 2001-2014 Joel de Guzman
Chris@102: 
Chris@102:     Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@102:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@102: ==============================================================================*/
Chris@102: #if !defined(BOOST_SPIRIT_X3_DETAIL_RULE_JAN_08_2012_0326PM)
Chris@102: #define BOOST_SPIRIT_X3_DETAIL_RULE_JAN_08_2012_0326PM
Chris@102: 
Chris@102: #if defined(_MSC_VER)
Chris@102: #pragma once
Chris@102: #endif
Chris@102: 
Chris@102: #include <boost/spirit/home/x3/core/parser.hpp>
Chris@102: #include <boost/spirit/home/x3/support/traits/make_attribute.hpp>
Chris@102: #include <boost/spirit/home/x3/support/utility/sfinae.hpp>
Chris@102: #include <boost/spirit/home/x3/nonterminal/detail/transform_attribute.hpp>
Chris@102: #include <boost/utility/addressof.hpp>
Chris@102: 
Chris@102: #if defined(BOOST_SPIRIT_X3_DEBUG)
Chris@102: #include <boost/spirit/home/x3/nonterminal/simple_trace.hpp>
Chris@102: #endif
Chris@102: 
Chris@102: namespace boost { namespace spirit { namespace x3
Chris@102: {
Chris@102:     template <typename ID>
Chris@102:     struct identity;
Chris@102:     
Chris@102:     template <typename ID, typename Attribute = unused_type>
Chris@102:     struct rule;
Chris@102: 
Chris@102:     struct parse_pass_context_tag;
Chris@102: 
Chris@102:     namespace detail
Chris@102:     {
Chris@102:         // we use this so we can detect if the default parse_rule
Chris@102:         // is the being called.
Chris@102:         struct default_parse_rule_result
Chris@102:         {
Chris@102:             default_parse_rule_result(bool r)
Chris@102:               : r(r) {}
Chris@102:             operator bool() const { return r; }
Chris@102:             bool r;
Chris@102:         };
Chris@102:     }
Chris@102:     
Chris@102:     // default parse_rule implementation
Chris@102:     template <typename ID, typename Attribute, typename Iterator
Chris@102:       , typename Context, typename ActualAttribute>
Chris@102:     inline detail::default_parse_rule_result
Chris@102:     parse_rule(
Chris@102:         rule<ID, Attribute> rule_
Chris@102:       , Iterator& first, Iterator const& last
Chris@102:       , Context const& context, ActualAttribute& attr);
Chris@102: }}}
Chris@102: 
Chris@102: namespace boost { namespace spirit { namespace x3 { namespace detail
Chris@102: {
Chris@102: #if defined(BOOST_SPIRIT_X3_DEBUG)
Chris@102:     template <typename Iterator, typename Attribute>
Chris@102:     struct context_debug
Chris@102:     {
Chris@102:         context_debug(
Chris@102:             char const* rule_name
Chris@102:           , Iterator const& first, Iterator const& last
Chris@102:           , Attribute const& attr
Chris@102:           , bool const& ok_parse //was parse successful?
Chris@102:           )
Chris@102:           : ok_parse(ok_parse), rule_name(rule_name)
Chris@102:           , first(first), last(last)
Chris@102:           , attr(attr)
Chris@102:           , f(detail::get_simple_trace())
Chris@102:         {
Chris@102:             f(first, last, attr, pre_parse, rule_name);
Chris@102:         }
Chris@102: 
Chris@102:         ~context_debug()
Chris@102:         {
Chris@102:             auto status = ok_parse ? successful_parse : failed_parse ;
Chris@102:             f(first, last, attr, status, rule_name);
Chris@102:         }
Chris@102: 
Chris@102:         bool const& ok_parse;
Chris@102:         char const* rule_name;
Chris@102:         Iterator const& first;
Chris@102:         Iterator const& last;
Chris@102:         Attribute const& attr;
Chris@102:         detail::simple_trace_type& f;
Chris@102:     };
Chris@102: #endif
Chris@102:     
Chris@102:     template <typename ID, typename Iterator, typename Context, typename Enable = void>
Chris@102:     struct has_on_error : mpl::false_ {};
Chris@102: 
Chris@102:     template <typename ID, typename Iterator, typename Context>
Chris@102:     struct has_on_error<ID, Iterator, Context,
Chris@102:         typename disable_if_substitution_failure<
Chris@102:             decltype(
Chris@102:                 std::declval<ID>().on_error(
Chris@102:                     std::declval<Iterator&>()
Chris@102:                   , std::declval<Iterator>()
Chris@102:                   , std::declval<expectation_failure<Iterator>>()
Chris@102:                   , std::declval<Context>()
Chris@102:                 )
Chris@102:             )>::type
Chris@102:         >
Chris@102:       : mpl::true_
Chris@102:     {};
Chris@102:     
Chris@102:     template <typename ID, typename Iterator, typename Attribute, typename Context, typename Enable = void>
Chris@102:     struct has_on_success : mpl::false_ {};
Chris@102: 
Chris@102:     template <typename ID, typename Iterator, typename Attribute, typename Context>
Chris@102:     struct has_on_success<ID, Iterator, Context, Attribute,
Chris@102:         typename disable_if_substitution_failure<
Chris@102:             decltype(
Chris@102:                 std::declval<ID>().on_success(
Chris@102:                     std::declval<Iterator&>()
Chris@102:                   , std::declval<Iterator>()
Chris@102:                   , std::declval<Attribute&>()
Chris@102:                   , std::declval<Context>()
Chris@102:                 )
Chris@102:             )>::type
Chris@102:         >
Chris@102:       : mpl::true_
Chris@102:     {};
Chris@102: 
Chris@102:     template <typename ID>
Chris@102:     struct make_id
Chris@102:     {
Chris@102:         typedef identity<ID> type;
Chris@102:     };
Chris@102: 
Chris@102:     template <typename ID>
Chris@102:     struct make_id<identity<ID>>
Chris@102:     {
Chris@102:         typedef identity<ID> type;
Chris@102:     };
Chris@102:     
Chris@102:     template <typename ID, typename RHS, typename Context>
Chris@102:     Context const&
Chris@102:     make_rule_context(RHS const& rhs, Context const& context
Chris@102:       , mpl::false_ /* is_default_parse_rule */)
Chris@102:     {
Chris@102:         return context;
Chris@102:     }
Chris@102:     
Chris@102:     template <typename ID, typename RHS, typename Context>
Chris@102:     auto make_rule_context(RHS const& rhs, Context const& context
Chris@102:       , mpl::true_ /* is_default_parse_rule */ )
Chris@102:     {
Chris@102:         return make_unique_context<ID>(rhs, context);
Chris@102:     }
Chris@102: 
Chris@102:     template <typename Attribute, typename ID>
Chris@102:     struct rule_parser
Chris@102:     {
Chris@102:         template <typename Iterator, typename Context, typename ActualAttribute>
Chris@102:         static bool call_on_success(
Chris@102:             Iterator& first, Iterator const& last
Chris@102:           , Context const& context, ActualAttribute& attr
Chris@102:           , mpl::false_ /* No on_success handler */ )
Chris@102:         {
Chris@102:             return true;
Chris@102:         }
Chris@102:         
Chris@102:         template <typename Iterator, typename Context, typename ActualAttribute>
Chris@102:         static bool call_on_success(
Chris@102:             Iterator& first, Iterator const& last
Chris@102:           , Context const& context, ActualAttribute& attr
Chris@102:           , mpl::true_ /* Has on_success handler */)
Chris@102:         {
Chris@102:             bool pass = true;
Chris@102:             ID().on_success(
Chris@102:                 first
Chris@102:               , last
Chris@102:               , attr
Chris@102:               , make_context<parse_pass_context_tag>(pass, context)
Chris@102:             );
Chris@102:             return pass;
Chris@102:         }
Chris@102:         
Chris@102:         template <typename RHS, typename Iterator, typename Context
Chris@102:           , typename RContext, typename ActualAttribute>
Chris@102:         static bool parse_rhs_main(
Chris@102:             RHS const& rhs
Chris@102:           , Iterator& first, Iterator const& last
Chris@102:           , Context const& context, RContext& rcontext, ActualAttribute& attr
Chris@102:           , mpl::false_)
Chris@102:         {
Chris@102:             // see if the user has a BOOST_SPIRIT_DEFINE for this rule
Chris@102:             typedef
Chris@102:                 decltype(parse_rule(
Chris@102:                     rule<ID, Attribute>(), first, last
Chris@102:                   , make_unique_context<ID>(rhs, context), attr))
Chris@102:             parse_rule_result;
Chris@102: 
Chris@102:             // If there is no BOOST_SPIRIT_DEFINE for this rule,
Chris@102:             // we'll make a context for this rule tagged by its ID
Chris@102:             // so we can extract the rule later on in the default
Chris@102:             // (generic) parse_rule function.
Chris@102:             typedef
Chris@102:                 is_same<parse_rule_result, default_parse_rule_result>
Chris@102:             is_default_parse_rule;
Chris@102: 
Chris@102:             Iterator i = first;
Chris@102:             bool r = rhs.parse(
Chris@102:                 i
Chris@102:               , last
Chris@102:               , make_rule_context<ID>(rhs, context, is_default_parse_rule())
Chris@102:               , rcontext
Chris@102:               , attr
Chris@102:             );
Chris@102: 
Chris@102:             if (r)
Chris@102:             {
Chris@102:                 auto first_ = first;
Chris@102:                 x3::skip_over(first_, last, context);
Chris@102:                 r = call_on_success(first_, i, context, attr
Chris@102:                   , has_on_success<ID, Iterator, Context, ActualAttribute>());
Chris@102:             }
Chris@102:             
Chris@102:             if (r)
Chris@102:                 first = i;
Chris@102:             return r;
Chris@102:         }
Chris@102: 
Chris@102:         template <typename RHS, typename Iterator, typename Context
Chris@102:           , typename RContext, typename ActualAttribute>
Chris@102:         static bool parse_rhs_main(
Chris@102:             RHS const& rhs
Chris@102:           , Iterator& first, Iterator const& last
Chris@102:           , Context const& context, RContext& rcontext, ActualAttribute& attr
Chris@102:           , mpl::true_ /* on_error is found */)
Chris@102:         {
Chris@102:             for (;;)
Chris@102:             {
Chris@102:                 try
Chris@102:                 {
Chris@102:                     return parse_rhs_main(
Chris@102:                         rhs, first, last, context, rcontext, attr, mpl::false_());
Chris@102:                 }
Chris@102:                 catch (expectation_failure<Iterator> const& x)
Chris@102:                 {
Chris@102:                     switch (ID().on_error(first, last, x, context))
Chris@102:                     {
Chris@102:                         case error_handler_result::fail:
Chris@102:                             return false;
Chris@102:                         case error_handler_result::retry:
Chris@102:                             continue;
Chris@102:                         case error_handler_result::accept:
Chris@102:                             return true;
Chris@102:                         case error_handler_result::rethrow:
Chris@102:                             throw;
Chris@102:                     }
Chris@102:                 }
Chris@102:             }
Chris@102:         }
Chris@102: 
Chris@102:         template <typename RHS, typename Iterator
Chris@102:           , typename Context, typename RContext, typename ActualAttribute>
Chris@102:         static bool parse_rhs_main(
Chris@102:             RHS const& rhs
Chris@102:           , Iterator& first, Iterator const& last
Chris@102:           , Context const& context, RContext& rcontext, ActualAttribute& attr)
Chris@102:         {
Chris@102:             return parse_rhs_main(
Chris@102:                 rhs, first, last, context, rcontext, attr
Chris@102:               , has_on_error<ID, Iterator, Context>()
Chris@102:             );
Chris@102:         }
Chris@102: 
Chris@102:         template <typename RHS, typename Iterator
Chris@102:           , typename Context, typename RContext, typename ActualAttribute>
Chris@102:         static bool parse_rhs(
Chris@102:             RHS const& rhs
Chris@102:           , Iterator& first, Iterator const& last
Chris@102:           , Context const& context, RContext& rcontext, ActualAttribute& attr
Chris@102:           , mpl::false_)
Chris@102:         {
Chris@102:             return parse_rhs_main(rhs, first, last, context, rcontext, attr);
Chris@102:         }
Chris@102: 
Chris@102:         template <typename RHS, typename Iterator
Chris@102:           , typename Context, typename RContext, typename ActualAttribute>
Chris@102:         static bool parse_rhs(
Chris@102:             RHS const& rhs
Chris@102:           , Iterator& first, Iterator const& last
Chris@102:           , Context const& context, RContext& rcontext, ActualAttribute& attr
Chris@102:           , mpl::true_)
Chris@102:         {
Chris@102:             return parse_rhs_main(rhs, first, last, context, rcontext, unused);
Chris@102:         }
Chris@102: 
Chris@102:         template <typename RHS, typename Iterator, typename Context
Chris@102:           , typename ActualAttribute, typename ExplicitAttrPropagation>
Chris@102:         static bool call_rule_definition(
Chris@102:             RHS const& rhs
Chris@102:           , char const* rule_name
Chris@102:           , Iterator& first, Iterator const& last
Chris@102:           , Context const& context, ActualAttribute& attr
Chris@102:           , ExplicitAttrPropagation)
Chris@102:         {
Chris@102:             typedef traits::make_attribute<Attribute, ActualAttribute> make_attribute;
Chris@102: 
Chris@102:             // do down-stream transformation, provides attribute for
Chris@102:             // rhs parser
Chris@102:             typedef traits::transform_attribute<
Chris@102:                 typename make_attribute::type, Attribute, parser_id>
Chris@102:             transform;
Chris@102: 
Chris@102:             typedef typename make_attribute::value_type value_type;
Chris@102:             typedef typename transform::type transform_attr;
Chris@102:             value_type made_attr = make_attribute::call(attr);
Chris@102:             transform_attr attr_ = transform::pre(made_attr);
Chris@102: 
Chris@102:             bool ok_parse
Chris@102:               //Creates a place to hold the result of parse_rhs
Chris@102:               //called inside the following scope.
Chris@102:               ;
Chris@102:             {
Chris@102:              //Create a scope to cause the dbg variable below (within
Chris@102:              //the #if...#endif) to call it's DTOR before any
Chris@102:              //modifications are made to the attribute, attr_ passed
Chris@102:              //to parse_rhs (such as might be done in
Chris@102:              //traits::post_transform when, for example,
Chris@102:              //ActualAttribute is a recursive variant).
Chris@102: #if defined(BOOST_SPIRIT_X3_DEBUG)
Chris@102:                   context_debug<Iterator, typename make_attribute::value_type>
Chris@102:                 dbg(rule_name, first, last, attr_, ok_parse);
Chris@102: #endif
Chris@102:                 ok_parse=parse_rhs(rhs, first, last, context, attr_, attr_
Chris@102:                    , mpl::bool_
Chris@102:                      < (  RHS::has_action 
Chris@102:                        && !ExplicitAttrPropagation::value
Chris@102:                        )
Chris@102:                      >()
Chris@102:                   );
Chris@102:             }
Chris@102:             if(ok_parse)
Chris@102:             {
Chris@102:                 // do up-stream transformation, this integrates the results
Chris@102:                 // back into the original attribute value, if appropriate
Chris@102:                 traits::post_transform(attr, attr_);
Chris@102:             }
Chris@102:             return ok_parse;
Chris@102:         }
Chris@102: 
Chris@102: //        template <typename RuleDef, typename Iterator, typename Context
Chris@102: //            , typename ActualAttribute, typename AttributeContext>
Chris@102: //        static bool call_from_rule(
Chris@102: //            RuleDef const& rule_def
Chris@102: //          , char const* rule_name
Chris@102: //          , Iterator& first, Iterator const& last
Chris@102: //          , Context const& context, ActualAttribute& attr, AttributeContext& attr_ctx)
Chris@102: //        {
Chris@102: //            // This is called when a rule-body has already been established.
Chris@102: //            // The rule body is already established by the rule_definition class,
Chris@102: //            // we will not do it again. We'll simply call the RHS by calling
Chris@102: //            // call_rule_definition.
Chris@102: //
Chris@102: //            return call_rule_definition(
Chris@102: //                rule_def.rhs, rule_name, first, last
Chris@102: //              , context, attr, attr_ctx.attr_ptr
Chris@102: //              , mpl::bool_<(RuleDef::explicit_attribute_propagation)>());
Chris@102: //        }
Chris@102: //
Chris@102: //        template <typename RuleDef, typename Iterator, typename Context
Chris@102: //            , typename ActualAttribute>
Chris@102: //        static bool call_from_rule(
Chris@102: //            RuleDef const& rule_def
Chris@102: //          , char const* rule_name
Chris@102: //          , Iterator& first, Iterator const& last
Chris@102: //          , Context const& context, ActualAttribute& attr, unused_type)
Chris@102: //        {
Chris@102: //            // This is called when a rule-body has *not yet* been established.
Chris@102: //            // The rule body is established by the rule_definition class, so
Chris@102: //            // we call it to parse and establish the rule-body.
Chris@102: //
Chris@102: //            return rule_def.parse(first, last, context, unused, attr); // $$$ fix unused param $$$
Chris@102: //        }
Chris@102:     };
Chris@102: }}}}
Chris@102: 
Chris@102: #endif