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/*=============================================================================
Copyright (c) 2003 Joel de Guzman
http://spirit.sourceforge.net/
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_SAFE_BOOL_HPP)
#define BOOST_SPIRIT_SAFE_BOOL_HPP
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>
#include <boost/spirit/home/classic/namespace.hpp>
namespace boost { namespace spirit {
BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
namespace impl
{
template <typename T>
struct no_base {};
template <typename T>
struct safe_bool_impl
{
#if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
void stub(T*) {};
typedef void (safe_bool_impl::*type)(T*);
#else
typedef T* TP; // workaround to make parsing easier
TP stub;
typedef TP safe_bool_impl::*type;
#endif
};
}
template <typename DerivedT, typename BaseT = impl::no_base<DerivedT> >
struct safe_bool : BaseT
{
private:
typedef impl::safe_bool_impl<DerivedT> impl_t;
typedef typename impl_t::type bool_type;
public:
operator bool_type() const
{
return static_cast<const DerivedT*>(this)->operator_bool() ?
&impl_t::stub : 0;
}
operator bool_type()
{
return static_cast<DerivedT*>(this)->operator_bool() ?
&impl_t::stub : 0;
}
};
BOOST_SPIRIT_CLASSIC_NAMESPACE_END
}}
#endif
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