boost/spirit/home/qi/meta_grammar.hpp

/*=============================================================================
    Copyright (c) 2001-2007 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_META_GRAMMAR_JAN_29_2007_0937AM)
#define BOOST_SPIRIT_META_GRAMMAR_JAN_29_2007_0937AM

#include <boost/spirit/home/support/meta_grammar/grammar.hpp>
#include <boost/spirit/home/support/meta_grammar/basic_transforms.hpp>
#include <boost/spirit/home/qi/domain.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/placeholders.hpp>

namespace boost { namespace spirit { namespace qi
{
    // Check if Expr is a valid RD expression
    template <typename Expr, typename Enable = void>
    struct is_valid_expr : mpl::false_ {};

    // Return a suitable transform for the given Expr
    template <typename Expr, typename Enable = void>
    struct expr_transform;

    struct main_meta_grammar
      : meta_grammar::if_transform<
            is_valid_expr<proto::_>() 
          , expr_transform<proto::_> 
        >
    {
    };
}}}

namespace boost { namespace spirit { namespace meta_grammar
{
    ///////////////////////////////////////////////////////////////////////////
    //  The spirit qi domain meta-grammar
    ///////////////////////////////////////////////////////////////////////////
    template <>
    struct grammar<qi::domain>
    {
        typedef qi::main_meta_grammar type;
    };
}}}

#endif