boost/spirit/home/qi/detail/unused_skipper.hpp
// Copyright (c) 2001-2011 Hartmut Kaiser
//
// 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_QI_UNUSED_SKIPPER_JUL_25_2009_0921AM)
#define BOOST_SPIRIT_QI_UNUSED_SKIPPER_JUL_25_2009_0921AM
#if defined(_MSC_VER)
#pragma once
#endif
#include <boost/spirit/home/support/unused.hpp>
#include <boost/mpl/bool.hpp>
namespace boost { namespace spirit { namespace qi { namespace detail
{
template <typename Skipper>
struct unused_skipper : unused_type
{
unused_skipper(Skipper const& skipper_)
: skipper(skipper_) {}
Skipper const& skipper;
private:
// silence MSVC warning C4512: assignment operator could not be generated
unused_skipper& operator= (unused_skipper const&);
};
template <typename Skipper>
struct is_unused_skipper
: mpl::false_ {};
template <typename Skipper>
struct is_unused_skipper<unused_skipper<Skipper> >
: mpl::true_ {};
template <>
struct is_unused_skipper<unused_type>
: mpl::true_ {};
// If a surrounding lexeme[] directive was specified, the current
// skipper is of the type unused_skipper. In this case we
// re-activate the skipper which was active before the skip[]
// directive.
template <typename Skipper>
inline Skipper const&
get_skipper(unused_skipper<Skipper> const& u)
{
return u.skipper;
}
// If no surrounding lexeme[] directive was specified we keep what we got.
template <typename Skipper>
inline Skipper const&
get_skipper(Skipper const& u)
{
return u;
}
}}}}
#endif