/*=============================================================================
    Spirit v1.6.0
    Copyright (c) 2002-2003 Joel de Guzman
    Copyright (c) 2002-2003 Hartmut Kaiser
    http://spirit.sourceforge.net/

    Permission to copy, use, modify, sell and distribute this software is
    granted provided this copyright notice appears in all copies. This
    software is provided "as is" without express or implied warranty, and
    with no claim as to its suitability for any purpose.
=============================================================================*/
#if !defined(BOOST_SPIRIT_TRAVERSE_HPP)
#define BOOST_SPIRIT_TRAVERSE_HPP

///////////////////////////////////////////////////////////////////////////////
// traverse code isn't supported on the VC6 platform (yet)
#if (!defined(BOOST_MSVC) || (BOOST_MSVC >= 1300))

///////////////////////////////////////////////////////////////////////////////
#include "boost/spirit/core/meta/impl/traverse.ipp"

namespace boost { namespace spirit {

///////////////////////////////////////////////////////////////////////////////
//
//  Post-order traversal of auxilliary parsers.
//
///////////////////////////////////////////////////////////////////////////////

struct post_order {

    //  Return the parser type, which is generated as the result of the
    //  traverse function below.

    template <typename MetaT, typename ParserT>
    struct result {

        typedef typename traverse_post_order_return<
                    MetaT, ParserT, traverse_post_order_env<0, 0, 0, 0>
                >::type
            type;
    };

    //  Traverse a given parser and refactor it with the help of the given
    //  MetaT metafunction template.

    template <typename MetaT, typename ParserT>
    static typename result<MetaT, ParserT>::type
    traverse(MetaT const &meta_, ParserT const &parser_)
    {
        typedef typename ParserT::parser_category_t parser_category_t;
        return impl::traverse_post_order<parser_category_t>::generate(
            meta_, parser_, traverse_post_order_env<0, 0, 0, 0>());
    }
};

///////////////////////////////////////////////////////////////////////////////
//
//  Transform policies
//
//      The following policy classes could be used to assemble some new
//      transformation metafunction which uses identity transformations for
//      some parser_category type parsers.
//
///////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////
//  transform plain parsers
template <typename TransformT>
struct plain_identity_policy {

    template <typename ParserT, typename EnvT>
    struct plain_result {

        // plain parsers should be embedded and returned correctly
        typedef typename ParserT::embed_t type;
//        typedef ParserT type;
    };

    template <typename ParserT, typename EnvT>
    typename parser_traversal_plain_result<TransformT, ParserT, EnvT>::type
    generate_plain(ParserT const &parser_, EnvT const &env) const
    {
        return parser_;
    }
};

//////////////////////////////////
//  transform unary parsers
#if defined(BOOST_MSVC) && (BOOST_MSVC <= 1300)

BOOST_SPIRIT_DEPENDENT_TEMPLATE_WRAPPER(
    unary_identity_policy_return_wrapper, result);

template <typename UnaryT, typename SubjectT>
struct unary_identity_policy_return {

    typedef typename UnaryT::parser_generator_t parser_generator_t;
    typedef typename impl::unary_identity_policy_return_wrapper<parser_generator_t>
        ::template result_<SubjectT>::type type;
};

#else

template <typename UnaryT, typename SubjectT>
struct unary_identity_policy_return {

    typedef typename UnaryT::parser_generator_t parser_generator_t;
    typedef typename parser_generator_t::template result<SubjectT>::type type;
};

#endif // defined(BOOST_MSVC) && (BOOST_MSVC <= 1300)

template <typename TransformT>
struct unary_identity_policy {

    template <typename UnaryT, typename SubjectT, typename EnvT>
    struct unary_result {

        typedef
            typename unary_identity_policy_return<UnaryT, SubjectT>::type
            type;
    };

    template <typename UnaryT, typename SubjectT, typename EnvT>
    typename parser_traversal_unary_result<
        TransformT, UnaryT, SubjectT, EnvT
    >::type
    generate_unary(UnaryT const &, SubjectT const &subject_, EnvT const &env) const
    {
        typedef typename UnaryT::parser_generator_t parser_generator_t;
        return parser_generator_t::template generate<SubjectT>(subject_);
    }
};

//////////////////////////////////
//  transform action parsers
template <typename TransformT>
struct action_identity_policy {

    template <typename ActionT, typename SubjectT, typename EnvT>
    struct action_result {

        typedef action<SubjectT, typename ActionT::predicate_t> type;
    };

    template <typename ActionT, typename SubjectT, typename EnvT>
    typename parser_traversal_action_result<
        TransformT, ActionT, SubjectT, EnvT
    >::type
    generate_action(ActionT const &action_, SubjectT const &subject_,
        EnvT const &env) const
    {
        return subject_[action_.predicate()];
    }
};

//////////////////////////////////
//  transform binary parsers
#if defined(BOOST_MSVC) && (BOOST_MSVC <= 1300)

BOOST_SPIRIT_DEPENDENT_TEMPLATE_WRAPPER2(
    binary_identity_policy_return_wrapper, result);

template <typename BinaryT, typename LeftT, typename RightT>
struct binary_identity_policy_return {

    typedef typename BinaryT::parser_generator_t parser_generator_t;
    typedef
        typename impl::binary_identity_policy_return_wrapper<parser_generator_t>
        ::template result_<LeftT, RightT>::type type;
};

#else

template <typename BinaryT, typename LeftT, typename RightT>
struct binary_identity_policy_return {

    typedef typename BinaryT::parser_generator_t parser_generator_t;
    typedef typename parser_generator_t
        ::template result<LeftT, RightT>::type type;
};

#endif // defined(BOOST_MSVC) && (BOOST_MSVC <= 1300)

template <typename TransformT>
struct binary_identity_policy {

    template <typename BinaryT, typename LeftT, typename RightT, typename EnvT>
    struct binary_result {

        typedef
            typename binary_identity_policy_return<BinaryT, LeftT, RightT>::type
            type;
    };

    template <typename BinaryT, typename LeftT, typename RightT, typename EnvT>
    typename parser_traversal_binary_result<
        TransformT, BinaryT, LeftT, RightT, EnvT
    >::type
    generate_binary(BinaryT const &, LeftT const& left_, RightT const& right_,
        EnvT const &env) const
    {
        typedef typename BinaryT::parser_generator_t parser_generator_t;
        return parser_generator_t::
            template generate<LeftT, RightT>(left_, right_);
    }
};

///////////////////////////////////////////////////////////////////////////////
//
//  transform_policies template
//
//      The transform_policies template metafunction could serve as a base
//      class for new metafunctions to be passed to the traverse meta template
//      (see above), where only minimal parts have to be overwritten.
//
///////////////////////////////////////////////////////////////////////////////

template <
    typename TransformT,
    typename PlainPolicyT = plain_identity_policy<TransformT>,
    typename UnaryPolicyT = unary_identity_policy<TransformT>,
    typename ActionPolicyT = action_identity_policy<TransformT>,
    typename BinaryPolicyT = binary_identity_policy<TransformT>
>
struct transform_policies :
    public PlainPolicyT,
    public UnaryPolicyT,
    public ActionPolicyT,
    public BinaryPolicyT
{
};

///////////////////////////////////////////////////////////////////////////////
//
//  Identity transformation
//
//      The identity_transform metafunction supplied to the traverse template
//      will generate a new parser, which will be exactly identical to the
//      parser given as the parameter to the traverse metafunction. I.e. the
//      following conceptual 'equation' will be always true:
//
//      some_parser == post_order::traverse(identity_transform(), some_parser)
//
///////////////////////////////////////////////////////////////////////////////

struct identity_transform : public transform_policies<identity_transform> {};

///////////////////////////////////////////////////////////////////////////////
}} // namespace boost::spirit

#endif // (!defined(BOOST_MSVC) || (BOOST_MSVC >= 1300))

#endif // !defined(BOOST_SPIRIT_TRAVERSE_HPP)
