Chris@16: //  Copyright (c) 2001-2011 Hartmut Kaiser
Chris@16: //
Chris@16: //  Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@16: //  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #if !defined(BOOST_SPIRIT_QI_UNUSED_SKIPPER_JUL_25_2009_0921AM)
Chris@16: #define BOOST_SPIRIT_QI_UNUSED_SKIPPER_JUL_25_2009_0921AM
Chris@16: 
Chris@16: #if defined(_MSC_VER)
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/spirit/home/support/unused.hpp>
Chris@101: #include <boost/mpl/bool.hpp>
Chris@16: 
Chris@16: namespace boost { namespace spirit { namespace qi { namespace detail
Chris@16: {
Chris@16:     template <typename Skipper>
Chris@16:     struct unused_skipper : unused_type
Chris@16:     {
Chris@16:         unused_skipper(Skipper const& skipper_)
Chris@16:           : skipper(skipper_) {}
Chris@16:         Skipper const& skipper;
Chris@16: 
Chris@16:     private:
Chris@16:         // silence MSVC warning C4512: assignment operator could not be generated
Chris@16:         unused_skipper& operator= (unused_skipper const&);
Chris@16:     };
Chris@16: 
Chris@101:     template <typename Skipper>
Chris@101:     struct is_unused_skipper
Chris@101:       : mpl::false_ {};
Chris@101: 
Chris@101:     template <typename Skipper>
Chris@101:     struct is_unused_skipper<unused_skipper<Skipper> >
Chris@101:       : mpl::true_ {};
Chris@101: 
Chris@101:     template <>
Chris@101:     struct is_unused_skipper<unused_type>
Chris@101:       : mpl::true_ {};
Chris@101: 
Chris@16:     // If a surrounding lexeme[] directive was specified, the current
Chris@101:     // skipper is of the type unused_skipper. In this case we
Chris@16:     // re-activate the skipper which was active before the skip[]
Chris@16:     // directive.
Chris@16:     template <typename Skipper>
Chris@101:     inline Skipper const&
Chris@16:     get_skipper(unused_skipper<Skipper> const& u)
Chris@16:     {
Chris@16:         return u.skipper;
Chris@16:     }
Chris@16: 
Chris@16:     // If no surrounding lexeme[] directive was specified we keep what we got.
Chris@16:     template <typename Skipper>
Chris@101:     inline Skipper const&
Chris@16:     get_skipper(Skipper const& u)
Chris@16:     {
Chris@16:         return u;
Chris@16:     }
Chris@16: 
Chris@16: }}}}
Chris@16: 
Chris@16: #endif