source: NonGTP/Boost/boost/spirit/meta/parser_traits.hpp @ 857

/*=============================================================================
    Copyright (c) 2002-2003 Joel de Guzman
    Copyright (c) 2002-2003 Hartmut Kaiser
    Copyright (c) 2003 Martin Wille
    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)
=============================================================================*/
#if !defined(BOOST_SPIRIT_PARSER_TRAITS_HPP)
#define BOOST_SPIRIT_PARSER_TRAITS_HPP

#include <boost/type_traits/is_base_and_derived.hpp>
#include <boost/static_assert.hpp>

#include <boost/spirit/core/parser.hpp>
#include <boost/spirit/meta/impl/parser_traits.ipp>

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

///////////////////////////////////////////////////////////////////////////////
//
//  Parser traits templates
//
//      Used to determine the type and several other characteristics of a given
//      parser type.
//
///////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////
//
// The is_parser traits template can be used to tell wether a given
// class is a parser.
//
///////////////////////////////////////////////////////////////////////////////
template <typename T>
struct is_parser
{
    BOOST_STATIC_CONSTANT(bool, value =
        (::boost::is_base_and_derived<parser<T>, T>::value));

//  [JDG 2/3/03] simplified implementation by
//  using boost::is_base_and_derived
};

///////////////////////////////////////////////////////////////////////////////
//
//  The is_unary_composite traits template can be used to tell if a given
//  parser is a unary parser as for instance kleene_star or optional.
//
///////////////////////////////////////////////////////////////////////////////
template <typename UnaryT>
struct is_unary_composite {

    BOOST_STATIC_CONSTANT(bool, value = (::boost::is_convertible<
        typename UnaryT::parser_category_t, unary_parser_category>::value));
};

///////////////////////////////////////////////////////////////////////////////
//
//  The is_acction_parser traits template can be used to tell if a given
//  parser is a action parser, i.e. it is a composite consisting of a
//  auxilliary parser and an attached semantic action.
//
///////////////////////////////////////////////////////////////////////////////
template <typename ActionT>
struct is_action_parser {

    BOOST_STATIC_CONSTANT(bool, value = (::boost::is_convertible<
        typename ActionT::parser_category_t, action_parser_category>::value));
};

///////////////////////////////////////////////////////////////////////////////
//
//  The is_binary_composite traits template can be used to tell if a given
//  parser is a binary parser as for instance sequence or difference.
//
///////////////////////////////////////////////////////////////////////////////
template <typename BinaryT>
struct is_binary_composite {

    BOOST_STATIC_CONSTANT(bool, value = (::boost::is_convertible<
        typename BinaryT::parser_category_t, binary_parser_category>::value));
};

///////////////////////////////////////////////////////////////////////////////
//
//  The is_composite_parser traits template can be used to tell if a given
//  parser is a unary or a binary parser composite type.
//
///////////////////////////////////////////////////////////////////////////////
template <typename CompositeT>
struct is_composite_parser {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::is_unary_composite<CompositeT>::value ||
        ::boost::spirit::is_binary_composite<CompositeT>::value));
};

///////////////////////////////////////////////////////////////////////////////
template <typename ParserT>
struct is_alternative {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_alternative));
};

template <typename ParserT>
struct is_sequence {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_sequence));
};

template <typename ParserT>
struct is_sequential_or {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_sequential_or));
};

template <typename ParserT>
struct is_intersection {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_intersection));
};

template <typename ParserT>
struct is_difference {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_difference));
};

template <typename ParserT>
struct is_exclusive_or {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_exclusive_or));
};

template <typename ParserT>
struct is_optional {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_optional));
};

template <typename ParserT>
struct is_kleene_star {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_kleene_star));
};

template <typename ParserT>
struct is_positive {

    BOOST_STATIC_CONSTANT(bool, value = (
        ::boost::spirit::impl::parser_type_traits<ParserT>::is_positive));
};

///////////////////////////////////////////////////////////////////////////////
//
//  Parser extraction templates
//
///////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////
//
//  The unary_subject template can be used to return the type of the
//  parser used as the subject of an unary parser.
//  If the parser under inspection is not an unary type parser the compilation
//  will fail.
//
///////////////////////////////////////////////////////////////////////////////
template <typename UnaryT>
struct unary_subject {

    BOOST_STATIC_ASSERT(::boost::spirit::is_unary_composite<UnaryT>::value);
    typedef typename UnaryT::subject_t type;
};

///////////////////////////////////////////////////////////////////////////////
//
//  The get_unary_subject template function returns the parser object, which
//  is used as the subject of an unary parser.
//  If the parser under inspection is not an unary type parser the compilation
//  will fail.
//
///////////////////////////////////////////////////////////////////////////////
template <typename UnaryT>
inline typename unary_subject<UnaryT>::type const &
get_unary_subject(UnaryT const &unary_)
{
    BOOST_STATIC_ASSERT(::boost::spirit::is_unary_composite<UnaryT>::value);
    return unary_.subject();
}

///////////////////////////////////////////////////////////////////////////////
//
//  The binary_left_subject and binary_right_subject templates can be used to
//  return the types of the parsers used as the left and right subject of an
//  binary parser.
//  If the parser under inspection is not a binary type parser the compilation
//  will fail.
//
///////////////////////////////////////////////////////////////////////////////
template <typename BinaryT>
struct binary_left_subject {

    BOOST_STATIC_ASSERT(::boost::spirit::is_binary_composite<BinaryT>::value);
    typedef typename BinaryT::left_t type;
};

template <typename BinaryT>
struct binary_right_subject {

    BOOST_STATIC_ASSERT(::boost::spirit::is_binary_composite<BinaryT>::value);
    typedef typename BinaryT::right_t type;
};

///////////////////////////////////////////////////////////////////////////////
//
//  The get_binary_left_subject and get_binary_right_subject template functions
//  return the parser object, which is used as the left or right subject of a
//  binary parser.
//  If the parser under inspection is not a binary type parser the compilation
//  will fail.
//
///////////////////////////////////////////////////////////////////////////////
template <typename BinaryT>
inline typename binary_left_subject<BinaryT>::type const &
get_binary_left_subject(BinaryT const &binary_)
{
    BOOST_STATIC_ASSERT(::boost::spirit::is_binary_composite<BinaryT>::value);
    return binary_.left();
}

template <typename BinaryT>
inline typename binary_right_subject<BinaryT>::type const &
get_binary_right_subject(BinaryT const &binary_)
{
    BOOST_STATIC_ASSERT(::boost::spirit::is_binary_composite<BinaryT>::value);
    return binary_.right();
}

///////////////////////////////////////////////////////////////////////////////
//
//  The action_subject template can be used to return the type of the
//  parser used as the subject of an action parser.
//  If the parser under inspection is not an action type parser the compilation
//  will fail.
//
///////////////////////////////////////////////////////////////////////////////
template <typename ActionT>
struct action_subject {

    BOOST_STATIC_ASSERT(::boost::spirit::is_action_parser<ActionT>::value);
    typedef typename ActionT::subject_t type;
};

///////////////////////////////////////////////////////////////////////////////
//
//  The get_action_subject template function returns the parser object, which
//  is used as the subject of an action parser.
//  If the parser under inspection is not an action type parser the compilation
//  will fail.
//
///////////////////////////////////////////////////////////////////////////////
template <typename ActionT>
inline typename action_subject<ActionT>::type const &
get_action_subject(ActionT const &action_)
{
    BOOST_STATIC_ASSERT(::boost::spirit::is_action_parser<ActionT>::value);
    return action_.subject();
}

///////////////////////////////////////////////////////////////////////////////
//
//  The semantic_action template can be used to return the type of the
//  attached semantic action of an action parser.
//  If the parser under inspection is not an action type parser the compilation
//  will fail.
//
///////////////////////////////////////////////////////////////////////////////
template <typename ActionT>
struct semantic_action {

    BOOST_STATIC_ASSERT(::boost::spirit::is_action_parser<ActionT>::value);
    typedef typename ActionT::predicate_t type;
};

///////////////////////////////////////////////////////////////////////////////
//
//  The get_semantic_action template function returns the attached semantic
//  action of an action parser.
//  If the parser under inspection is not an action type parser the compilation
//  will fail.
//
///////////////////////////////////////////////////////////////////////////////
template <typename ActionT>
inline typename semantic_action<ActionT>::type const &
get_semantic_action(ActionT const &action_)
{
    BOOST_STATIC_ASSERT(::boost::spirit::is_action_parser<ActionT>::value);
    return action_.predicate();
}

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

#endif // !defined(BOOST_SPIRIT_PARSER_TRAITS_HPP)