/*=============================================================================
    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_EPS_MARCH_23_2007_0454PM)
#define BOOST_SPIRIT_X3_EPS_MARCH_23_2007_0454PM

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

namespace boost {
namespace spirit {
namespace x3 {
struct rule_context_tag;

struct semantic_predicate : parser<semantic_predicate>
{
    typedef unused_type attribute_type;
    static bool const has_attribute = false;

    constexpr
    semantic_predicate(bool predicate)
        : predicate(predicate) {}

    template <typename Iterator, typename Context, typename Attribute>
    bool
    parse(Iterator& first, Iterator const& last
          , Context const& context, unused_type, Attribute&) const
    {
        x3::skip_over(first, last, context);
        return predicate;
    }

    bool predicate;
};

template <typename F>
struct lazy_semantic_predicate : parser<lazy_semantic_predicate<F>>
{
    typedef unused_type attribute_type;
    static bool const has_attribute = false;

    constexpr
    lazy_semantic_predicate(F f)
        : f(f) {}

    template <typename Iterator, typename Context, typename Attribute>
    bool
    parse(Iterator& first, Iterator const& last
          , Context const& context, unused_type, Attribute& /* attr */) const
    {
        x3::skip_over(first, last, context);
        return f(x3::get<rule_context_tag>(context));
    }

    F f;
};

struct eps_parser : parser<eps_parser>
{
    typedef unused_type attribute_type;
    static bool const has_attribute = false;

    template <typename Iterator, typename Context
    , typename RuleContext, typename Attribute>
    bool
    parse(Iterator& first, Iterator const& last
    , Context const& context, RuleContext&, Attribute&) const
    {
        x3::skip_over(first, last, context);
        return true;
    }

    constexpr semantic_predicate
    operator()(bool predicate) const
    {
        return { predicate };
    }

    template <typename F>
    constexpr lazy_semantic_predicate<F>
    operator()(F f) const
    {
        return { f };
    }
};

constexpr auto eps = eps_parser{};
}
}
}

#endif
