boost/boost/spirit/home/x3/directive/skip.hpp

/*=============================================================================
    Copyright (c) 2001-2014 Joel de Guzman
    Copyright (c) 2013 Agustin Berge

    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(SPIRIT_SKIP_JANUARY_26_2008_0422PM)
#define SPIRIT_SKIP_JANUARY_26_2008_0422PM

#if defined(_MSC_VER)
#pragma once
#endif

#include <boost/spirit/home/x3/support/context.hpp>
#include <boost/spirit/home/x3/support/unused.hpp>
#include <boost/spirit/home/x3/core/skip_over.hpp>
#include <boost/spirit/home/x3/core/parser.hpp>
#include <boost/utility/enable_if.hpp>

namespace boost { namespace spirit { namespace x3
{
    template <typename Subject>
    struct reskip_directive : unary_parser<Subject, reskip_directive<Subject>>
    {
        typedef unary_parser<Subject, reskip_directive<Subject>> base_type;
        static bool const is_pass_through_unary = true;
        static bool const handles_container = Subject::handles_container;

        reskip_directive(Subject const& subject)
          : base_type(subject) {}

        template <typename Iterator, typename Context
          , typename RContext, typename Attribute>
        typename disable_if<has_skipper<Context>, bool>::type
        parse(Iterator& first, Iterator const& last
          , Context const& context, RContext& rcontext, Attribute& attr) const
        {
            auto const& skipper =
                detail::get_unused_skipper(x3::get<skipper_tag>(context));

            return this->subject.parse(
                first, last
              , make_context<skipper_tag>(skipper, context)
              , rcontext
              , attr);
        }
        template <typename Iterator, typename Context
          , typename RContext, typename Attribute>
        typename enable_if<has_skipper<Context>, bool>::type
        parse(Iterator& first, Iterator const& last
          , Context const& context, RContext& rcontext, Attribute& attr) const
        {
            return this->subject.parse(
                first, last
              , context
              , rcontext
              , attr);
        }
    };

    template <typename Subject, typename Skipper>
    struct skip_directive : unary_parser<Subject, skip_directive<Subject, Skipper>>
    {
        typedef unary_parser<Subject, skip_directive<Subject, Skipper>> base_type;
        static bool const is_pass_through_unary = true;
        static bool const handles_container = Subject::handles_container;

        skip_directive(Subject const& subject, Skipper const& skipper)
          : base_type(subject)
          , skipper(skipper)
        {}

        template <typename Iterator, typename Context
          , typename RContext, typename Attribute>
        bool parse(Iterator& first, Iterator const& last
          , Context const& context, RContext& rcontext, Attribute& attr) const
        {
            return this->subject.parse(
                first, last
              , make_context<skipper_tag>(skipper, context)
              , rcontext
              , attr);
        }

        Skipper const skipper;
    };

    struct reskip_gen
    {
        template <typename Skipper>
        struct skip_gen
        {
            explicit skip_gen(Skipper const& skipper)
              : skipper_(skipper) {}

            template <typename Subject>
            skip_directive<typename extension::as_parser<Subject>::value_type, Skipper>
            operator[](Subject const& subject) const
            {
                return {as_parser(subject), skipper_};
            }

            Skipper skipper_;
        };
        
        template <typename Skipper>
        skip_gen<Skipper> const operator()(Skipper const& skipper) const
        {
            return skip_gen<Skipper>(skipper);
        }

        template <typename Subject>
        reskip_directive<typename extension::as_parser<Subject>::value_type>
        operator[](Subject const& subject) const
        {
            return {as_parser(subject)};
        }
    };

    reskip_gen const skip = reskip_gen();
}}}

#endif