rule.ipp

Boost provides free peer-reviewed portable C++ source libraries. We emphasize libraries that work

/*=============================================================================
    Copyright (c) 1998-2003 Joel de Guzman
    http://spirit.sourceforge.net/

    Use, modification and distribution is subject to the Boost Software
    License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
    http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#if !defined(BOOST_SPIRIT_RULE_IPP)
#define BOOST_SPIRIT_RULE_IPP

#if BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT > 1
#include <boost/preprocessor/repeat.hpp>
#include <boost/preprocessor/repeat_from_to.hpp>
#include <boost/preprocessor/enum_params.hpp>
#include <boost/preprocessor/enum_params_with_defaults.hpp>
#include <boost/preprocessor/facilities/intercept.hpp>
#include <boost/preprocessor/inc.hpp>
#include <boost/preprocessor/cat.hpp>
#endif

#include <boost/spirit/home/classic/core/parser.hpp>
#include <boost/spirit/home/classic/core/scanner/scanner.hpp>
#include <boost/spirit/home/classic/core/non_terminal/parser_context.hpp>
#include <boost/spirit/home/classic/core/non_terminal/parser_id.hpp>
#include <boost/type_traits/is_base_and_derived.hpp>

///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit {

BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN

#if BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT > 1

        template <
            BOOST_PP_ENUM_BINARY_PARAMS(
                BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT,
                typename ScannerT, = mpl::void_ BOOST_PP_INTERCEPT
            )
        >
        struct scanner_list;

#endif // BOOST_SPIRIT_RULE_SCANNERTYPE_LIMIT > 1

    ///////////////////////////////////////////////////////////////////////////
    namespace impl
    {
        template <typename BaseT, typename DefaultT
            , typename T0, typename T1, typename T2>
        struct get_param
        {
            typedef typename mpl::if_<
                is_base_and_derived<BaseT, T0>
              , T0
              , typename mpl::if_<
                    is_base_and_derived<BaseT, T1>
                  , T1
                  , typename mpl::if_<
                        is_base_and_derived<BaseT, T2>
                      , T2
                      , DefaultT
                    >::type
                >::type
            >::type type;
        };

        template <typename T0, typename T1, typename T2>
        struct get_context
        {
            typedef typename get_param<
                parser_context_base, parser_context<>, T0, T1, T2>::type
            type;
        };

        template <typename T0, typename T1, typename T2>
        struct get_tag
        {
            typedef typename get_param<
                parser_tag_base, parser_address_tag, T0, T1, T2>::type
            type;
        };

        template <typename T0, typename T1, typename T2>
        struct get_scanner
        {
            typedef typename get_param<
                scanner_base, scanner<>, T0, T1, T2>::type
            type;
        };

        ///////////////////////////////////////////////////////////////////////
        //
        //  rule_base class
        //
        //      The rule_base class implements the basic plumbing for rules
        //      minus the storage mechanism. It is up to the derived class
        //      to actually store the definition somewhere. The rule_base
        //      class assumes that the derived class provides a get() function
        //      that will return a pointer to a parser. The get() function
        //      may return NULL. See rule below for details.
        //
        //      <<< For framework use only. Not for public consumption. >>>
        //
        ///////////////////////////////////////////////////////////////////////
        template <
            typename DerivedT       // derived class
          , typename EmbedT         // how derived class is embedded
          , typename T0 = nil_t     // see rule class
          , typename T1 = nil_t     // see rule class
          , typename T2 = nil_t     // see rule class
        >
        class rule_base; // forward declaration

        class rule_base_access
        {
#if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) \
    || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x551))
        public: // YUCK!
#else
            template <
                typename DerivedT
              , typename EmbedT
              , typename T0
              , typename T1
              , typename T2
            >
           friend class rule_base;
#endif
            template <typename RuleT>
            static typename RuleT::abstract_parser_t*
            get(RuleT const& r)
            {
                return r.get();
            }
        };

        template <
            typename DerivedT       // derived class
          , typename EmbedT         // how derived class is embedded
          , typename T0             // see rule class
          , typename T1             // see rule class
          , typename T2             // see rule class
        >
        class rule_base
            : public parser<DerivedT>
            , public impl::get_context<T0, T1, T2>::type::base_t
            , public context_aux<
                typename impl::get_context<T0, T1, T2>::type, DerivedT>
            , public impl::get_tag<T0, T1, T2>::type
        {
        public:

            typedef typename impl::get_scanner<T0, T1, T2>::type scanner_t;
            typedef typename impl::get_context<T0, T1, T2>::type context_t;
            typedef typename impl::get_tag<T0, T1, T2>::type tag_t;

            typedef EmbedT embed_t;
            typedef typename context_t::context_linker_t linked_context_t;
            typedef typename linked_context_t::attr_t attr_t;

            template <typename ScannerT>
            struct result
            {
                typedef typename match_result<ScannerT, attr_t>::type type;
            };

            template <typename ScannerT>
            typename parser_result<DerivedT, ScannerT>::type
            parse(ScannerT const& scan) const
            {
                typedef parser_scanner_linker<ScannerT> linked_scanner_t;
                typedef typename parser_result<DerivedT, ScannerT>::type result_t;
                BOOST_SPIRIT_CONTEXT_PARSE(
                    scan, *this, linked_scanner_t, linked_context_t, result_t);
            }

            template <typename ScannerT>
            typename parser_result<DerivedT, ScannerT>::type
            parse_main(ScannerT const& scan) const
            {
                typename parser_result<DerivedT, ScannerT>::type hit;

                //  MWCW 8.3 needs this cast to be done through a pointer,
                //  not a reference. Otherwise, it will silently construct
                //  a temporary, causing an infinite runtime recursion.
                DerivedT const* derived_this = static_cast<DerivedT const*>(this);

                if (rule_base_access::get(*derived_this))
                {
                    typename ScannerT::iterator_t s(scan.first);
                    hit = rule_base_access::get(*derived_this)
                            ->do_parse_virtual(scan);
                    scan.group_match(hit, this->id(), s, scan.first);
                }
                else
                {
                    hit = scan.no_match();
                }
                return hit;
            }
        };

        ///////////////////////////////////////////////////////////////////////
        //
        //  abstract_parser class
        //