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

    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_X3_LEXEME_MARCH_24_2007_0802AM)
#define BOOST_SPIRIT_X3_LEXEME_MARCH_24_2007_0802AM

#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/type_traits/remove_reference.hpp>
#include <boost/utility/enable_if.hpp>

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

    constexpr
    lexeme_directive(Subject const& subject)
        : base_type(subject) {}

    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
    {
        x3::skip_over(first, last, context);
        auto const& skipper = x3::get<skipper_tag>(context);

        typedef unused_skipper<
        typename remove_reference<decltype(skipper)>::type>
        unused_skipper_type;
        unused_skipper_type unused_skipper(skipper);

        return this->subject.parse(
                   first, last
                   , make_context<skipper_tag>(unused_skipper, context)
                   , rcontext
                   , attr);
    }

    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
    {
        //  no need to pre-skip if skipper is unused
        return this->subject.parse(
                   first, last
                   , context
                   , rcontext
                   , attr);
    }
};

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

constexpr auto lexeme = lexeme_gen{};
}
}
}

#endif
