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+/*=============================================================================
+    Copyright (c) 2002-2003 Joel de Guzman
+    Copyright (c) 2002-2003 Hartmut Kaiser
+    http://spirit.sourceforge.net/
+
+  Distributed under 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_PARSER_CONTEXT_HPP)
+#define BOOST_SPIRIT_PARSER_CONTEXT_HPP
+
+///////////////////////////////////////////////////////////////////////////////
+namespace boost
+{
+    namespace spirit
+    {
+    BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
+
+
+    ///////////////////////////////////////////////////////////////////////////
+    //
+    //  default_parser_context_base class { default context base }
+    //
+    ///////////////////////////////////////////////////////////////////////////
+    struct default_parser_context_base
+    {
+        template <typename DerivedT>
+        struct aux {};
+    };
+
+    ///////////////////////////////////////////////////////////////////////////
+    //
+    //  parser_context_base class { base class of all context classes }
+    //
+    ///////////////////////////////////////////////////////////////////////////
+    struct parser_context_base {};
+
+    ///////////////////////////////////////////////////////////////////////////
+    //
+    //  parser_context class { default context }
+    //
+    ///////////////////////////////////////////////////////////////////////////
+    struct nil_t;
+    template<typename ContextT> struct parser_context_linker;
+
+    template<typename AttrT = nil_t>
+    struct parser_context : parser_context_base
+    {
+        typedef AttrT attr_t;
+        typedef default_parser_context_base base_t;
+        typedef parser_context_linker<parser_context<AttrT> > context_linker_t;
+
+        template <typename ParserT>
+        parser_context(ParserT const&) {}
+
+        template <typename ParserT, typename ScannerT>
+        void
+        pre_parse(ParserT const&, ScannerT const&) {}
+
+        template <typename ResultT, typename ParserT, typename ScannerT>
+        ResultT&
+        post_parse(ResultT& hit, ParserT const&, ScannerT const&)
+        { return hit; }
+    };
+
+    ///////////////////////////////////////////////////////////////////////////
+    //
+    //  context_aux class
+    //
+    //      context_aux<ContextT, DerivedT> is a class derived from the
+    //      ContextT's nested base_t::base<DerivedT> template class. (see
+    //      default_parser_context_base::aux for an example).
+    //
+    //      Basically, this class provides ContextT dependent optional
+    //      functionality to the derived class DerivedT through the CRTP
+    //      idiom (Curiously recurring template pattern).
+    //
+    ///////////////////////////////////////////////////////////////////////////
+    template <typename ContextT, typename DerivedT>
+    struct context_aux : public ContextT::base_t::template aux<DerivedT> {};
+
+    ///////////////////////////////////////////////////////////////////////////
+    //
+    //  parser_scanner_linker and parser_scanner_linker classes
+    //  { helper templates for the rule extensibility }
+    //
+    //      This classes can be 'overloaded' (defined elsewhere), to plug
+    //      in additional functionality into the non-terminal parsing process.
+    //
+    ///////////////////////////////////////////////////////////////////////////
+    #if !defined(BOOST_SPIRIT_PARSER_SCANNER_LINKER_DEFINED)
+    #define BOOST_SPIRIT_PARSER_SCANNER_LINKER_DEFINED
+
+    template<typename ScannerT>
+    struct parser_scanner_linker : public ScannerT
+    {
+        parser_scanner_linker(ScannerT const scan_) : ScannerT(scan_) {}
+    };
+
+    #endif // !defined(BOOST_SPIRIT_PARSER_SCANNER_LINKER_DEFINED)
+
+    //////////////////////////////////
+    #if !defined(BOOST_SPIRIT_PARSER_CONTEXT_LINKER_DEFINED)
+    #define BOOST_SPIRIT_PARSER_CONTEXT_LINKER_DEFINED
+
+    template<typename ContextT>
+    struct parser_context_linker : public ContextT
+    {
+        template <typename ParserT>
+        parser_context_linker(ParserT const& p)
+        : ContextT(p) {}
+
+        template <typename ParserT, typename ScannerT>
+        void pre_parse(ParserT const& p, ScannerT const& scan)
+        { ContextT::pre_parse(p, scan); }
+
+        template <typename ResultT, typename ParserT, typename ScannerT>
+        ResultT&
+        post_parse(ResultT& hit, ParserT const& p, ScannerT const& scan)
+        { return ContextT::post_parse(hit, p, scan); }
+    };
+
+    #endif // !defined(BOOST_SPIRIT_PARSER_CONTEXT_LINKER_DEFINED)
+
+    ///////////////////////////////////////////////////////////////////////////
+    //
+    //  BOOST_SPIRIT_CONTEXT_PARSE helper macro
+    //
+    //      The original implementation uses a template class. However, we
+    //      need to lessen the template instantiation depth to help inferior
+    //      compilers that sometimes choke on deep template instantiations.
+    //      The objective is to avoid code redundancy. A macro, in this case
+    //      is an obvious solution. Sigh!
+    //
+    //      WARNING: INTERNAL USE ONLY. NOT FOR PUBLIC CONSUMPTION.
+    //
+    ///////////////////////////////////////////////////////////////////////////
+    #define BOOST_SPIRIT_CONTEXT_PARSE(scan, this_, scanner_t, context_t, result_t) \
+            scanner_t scan_wrap(scan);                                              \
+            context_t context_wrap(this_);                                          \
+            context_wrap.pre_parse(this_, scan_wrap);                               \
+            result_t hit = parse_main(scan);                                        \
+            return context_wrap.post_parse(hit, this_, scan_wrap);
+
+    BOOST_SPIRIT_CLASSIC_NAMESPACE_END
+
+    } // namespace spirit
+} // namespace boost
+
+#endif