closure.hpp

C++的一个好库。。。现在很流行

/*=============================================================================
    Copyright (c) 2001-2003 Joel de Guzman
    Copyright (c) 2002-2003 Hartmut Kaiser
    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)
=============================================================================*/
#ifndef BOOST_SPIRIT_CLOSURE_HPP
#define BOOST_SPIRIT_CLOSURE_HPP

///////////////////////////////////////////////////////////////////////////////
#include <boost/spirit/core/parser.hpp>
#include <boost/spirit/core/composite/composite.hpp>
#include <boost/spirit/attribute/parametric.hpp>
#include <boost/spirit/attribute/closure_context.hpp>

#include <boost/spirit/phoenix/closures.hpp>
#include <boost/spirit/phoenix/primitives.hpp>
#include <boost/spirit/phoenix/casts.hpp>
#include <boost/spirit/phoenix/operators.hpp>
#include <boost/spirit/phoenix/tuple_helpers.hpp>

#include <boost/static_assert.hpp>

///////////////////////////////////////////////////////////////////////////////
//
//  Spirit predefined maximum closure limit. This limit defines the maximum
//  number of elements a closure can hold. This number defaults to 3. The
//  actual maximum is rounded up in multiples of 3. Thus, if this value
//  is 4, the actual limit is 6. The ultimate maximum limit in this
//  implementation is 15.
//
//  It should NOT be greater than PHOENIX_LIMIT!
//
///////////////////////////////////////////////////////////////////////////////

#if !defined(BOOST_SPIRIT_CLOSURE_LIMIT)
#define BOOST_SPIRIT_CLOSURE_LIMIT PHOENIX_LIMIT
#endif

///////////////////////////////////////////////////////////////////////////////
//
// ensure BOOST_SPIRIT_CLOSURE_LIMIT <= PHOENIX_LIMIT and SPIRIT_CLOSURE_LIMIT <= 15
//
///////////////////////////////////////////////////////////////////////////////
BOOST_STATIC_ASSERT(BOOST_SPIRIT_CLOSURE_LIMIT <= PHOENIX_LIMIT);
BOOST_STATIC_ASSERT(BOOST_SPIRIT_CLOSURE_LIMIT <= 15);

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

    ///////////////////////////////////////////////////////////////////////////
    //
    //  closure_context class
    //
    ///////////////////////////////////////////////////////////////////////////
    template <typename ClosureT>
    class closure_context : public parser_context_base
    {
    public:

        typedef typename phoenix::tuple_element<0,
            typename ClosureT::tuple_t>::type attr_t;
        typedef ClosureT base_t;
        typedef closure_context_linker<closure_context<ClosureT> >
        context_linker_t;

        closure_context(ClosureT const& clos)
        : frame(clos) {}

        ~closure_context() {}

        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&)
        { hit.value(frame[phoenix::tuple_index<0>()]); return hit; }

    private:

        phoenix::closure_frame<typename ClosureT::phoenix_closure_t> frame;
    };

    ///////////////////////////////////////////////////////////////////////////
    //
    //  init_closure_context class
    //
    //      The init_closure_context class is a special parser context type
    //      which additionally initializes a closure contained in the derived
    //      parser with values from a given tuple. Please note, that this
    //      given tuple does not contain the required values directly, it
    //      contains phoenix::actor objects. These actors have to be
    //      dereferenced to gain the values to be used for initialization
    //      (this is done by the help of the phoenix::convert_actors<>
    //      template).
    //
    ///////////////////////////////////////////////////////////////////////////

    template <typename ClosureT>
    class init_closure_context : public parser_context_base
    {
        typedef typename ClosureT::tuple_t      tuple_t;
        typedef typename ClosureT::closure_t    closure_t;

    public:

        init_closure_context(ClosureT const& clos)
        : frame(clos.subject(), phoenix::convert_actors<tuple_t>(clos.init)) {}

        ~init_closure_context() {}

        template <typename ParserT, typename ScannerT>
        void pre_parse(ParserT const& /*p*/, ScannerT const&) {}

        template <typename ResultT, typename ParserT, typename ScannerT>
        ResultT& post_parse(ResultT& hit, ParserT const&, ScannerT const&)
        { hit.value(frame[phoenix::tuple_index<0>()]); return hit; }

    private:

        phoenix::closure_frame<closure_t> frame;
    };

    ///////////////////////////////////////////////////////////////////////////
    //
    //  init_closure_parser class
    //
    ///////////////////////////////////////////////////////////////////////////
    template <typename ParserT, typename ActorTupleT>
    struct init_closure_parser
    : public unary<ParserT, parser<init_closure_parser<ParserT, ActorTupleT> > >
    {
        typedef init_closure_parser<ParserT, ActorTupleT>           self_t;
        typedef unary<ParserT, parser<self_t> >                     base_t;
        typedef typename ParserT::phoenix_closure_t                 closure_t;
        typedef typename ParserT::tuple_t                           tuple_t;
        typedef typename phoenix::tuple_element<0, tuple_t>::type   attr_t;

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

        init_closure_parser(ParserT const& p, ActorTupleT const& init_)
        : base_t(p), init(init_) {}

        template <typename ScannerT>
        typename parser_result<self_t, ScannerT>::type
        parse_main(ScannerT const& scan) const
        {
            return this->subject().parse_main(scan);
        }

        template <typename ScannerT>
        typename parser_result<self_t, ScannerT>::type
        parse(ScannerT const& scan) const
        {
            typedef init_closure_context<self_t> init_context_t;
            typedef parser_scanner_linker<ScannerT> scanner_t;
            typedef closure_context_linker<init_context_t> context_t;
            typedef typename parser_result<self_t, ScannerT>::type result_t;
            BOOST_SPIRIT_CONTEXT_PARSE(
                scan, *this, scanner_t, context_t, result_t);
        }

        ActorTupleT init;
    };

    ///////////////////////////////////////////////////////////////////////////
    //
    //  closure class
    //
    ///////////////////////////////////////////////////////////////////////////
    template <
            typename DerivedT
        ,   typename T0 = phoenix::nil_t
        ,   typename T1 = phoenix::nil_t
        ,   typename T2 = phoenix::nil_t

    #if BOOST_SPIRIT_CLOSURE_LIMIT > 3
        ,   typename T3 = phoenix::nil_t
        ,   typename T4 = phoenix::nil_t
        ,   typename T5 = phoenix::nil_t

    #if BOOST_SPIRIT_CLOSURE_LIMIT > 6
        ,   typename T6 = phoenix::nil_t
        ,   typename T7 = phoenix::nil_t
        ,   typename T8 = phoenix::nil_t

    #if BOOST_SPIRIT_CLOSURE_LIMIT > 9
        ,   typename T9 = phoenix::nil_t
        ,   typename T10 = phoenix::nil_t
        ,   typename T11 = phoenix::nil_t

    #if BOOST_SPIRIT_CLOSURE_LIMIT > 12
        ,   typename T12 = phoenix::nil_t
        ,   typename T13 = phoenix::nil_t
        ,   typename T14 = phoenix::nil_t

    #endif
    #endif
    #endif
    #endif
    >
    struct closure :
        public phoenix::closure<
            T0, T1, T2
    #if BOOST_SPIRIT_CLOSURE_LIMIT > 3
        ,   T3, T4, T5
    #if BOOST_SPIRIT_CLOSURE_LIMIT > 6
        ,   T6, T7, T8
    #if BOOST_SPIRIT_CLOSURE_LIMIT > 9
        ,   T9, T10, T11
    #if BOOST_SPIRIT_CLOSURE_LIMIT > 12
        ,   T12, T13, T14
    #endif
    #endif
    #endif
    #endif
        >
    {
        typedef phoenix::closure<
                T0, T1, T2
    #if BOOST_SPIRIT_CLOSURE_LIMIT > 3
            ,   T3, T4, T5
    #if BOOST_SPIRIT_CLOSURE_LIMIT > 6
            ,   T6, T7, T8
    #if BOOST_SPIRIT_CLOSURE_LIMIT > 9
            ,   T9, T10, T11
    #if BOOST_SPIRIT_CLOSURE_LIMIT > 12
            ,   T12, T13, T14
    #endif
    #endif
    #endif
    #endif
            > phoenix_closure_t;

        typedef closure_context<DerivedT> context_t;

        template <typename DerivedT2>
        struct aux
        {
            DerivedT2& aux_derived()
            { return *static_cast<DerivedT2*>(this); }

            DerivedT2 const& aux_derived() const
            { return *static_cast<DerivedT2 const*>(this); }

        // initialization functions
            template <typename A>
            init_closure_parser<
                DerivedT2,
                phoenix::tuple<
                    typename phoenix::as_actor<A>::type
                >
            >
            operator()(A const &a) const
            {
                typedef typename phoenix::as_actor<A>::type a_t;
                typedef phoenix::tuple<a_t> actor_tuple_t;

                return init_closure_parser<DerivedT2, actor_tuple_t>(
                        aux_derived(),
                        actor_tuple_t(
                            phoenix::as_actor<A>::convert(a)
                        )