96 lines
2.7 KiB
C++
96 lines
2.7 KiB
C++
|
//-----------------------------------------------------------------------------
|
||
|
|
// boost variant/static_visitor.hpp header file
|
||
|
|
// See http://www.boost.org for updates, documentation, and revision history.
|
||
|
|
//-----------------------------------------------------------------------------
|
||
|
|
//
|
||
|
|
// Copyright (c) 2002-2003
|
||
|
|
// Eric Friedman
|
||
|
|
//
|
||
|
|
// 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)
|
||
|
|
|
||
|
|
#ifndef BOOST_VARIANT_STATIC_VISITOR_HPP
|
||
|
|
#define BOOST_VARIANT_STATIC_VISITOR_HPP
|
||
|
|
|
||
|
|
#include <boost/config.hpp>
|
||
|
|
#include <boost/detail/workaround.hpp>
|
||
|
|
|
||
|
|
#include <boost/mpl/if.hpp>
|
||
|
|
#include <boost/type_traits/is_base_and_derived.hpp>
|
||
|
|
|
||
|
|
#include <boost/type_traits/integral_constant.hpp>
|
||
|
|
#include <boost/mpl/aux_/lambda_support.hpp>
|
||
|
|
|
||
|
|
namespace boost {
|
||
|
|
|
||
|
|
//////////////////////////////////////////////////////////////////////////
|
||
|
|
// class template static_visitor
|
||
|
|
//
|
||
|
|
// An empty base class that typedefs the return type of a deriving static
|
||
|
|
// visitor. The class is analogous to std::unary_function in this role.
|
||
|
|
//
|
||
|
|
|
||
|
|
namespace detail {
|
||
|
|
|
||
|
|
struct is_static_visitor_tag { };
|
||
|
|
|
||
|
|
typedef void static_visitor_default_return;
|
||
|
|
|
||
|
|
} // namespace detail
|
||
|
|
|
||
|
|
template <typename R = ::boost::detail::static_visitor_default_return>
|
||
|
|
class static_visitor
|
||
|
|
: public detail::is_static_visitor_tag
|
||
|
|
{
|
||
|
|
public: // typedefs
|
||
|
|
|
||
|
|
typedef R result_type;
|
||
|
|
|
||
|
|
protected: // for use as base class only
|
||
|
|
#if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS) && !defined(BOOST_NO_CXX11_NON_PUBLIC_DEFAULTED_FUNCTIONS)
|
||
|
|
static_visitor() = default;
|
||
|
|
~static_visitor() = default;
|
||
|
|
#else
|
||
|
|
static_visitor() BOOST_NOEXCEPT { }
|
||
|
|
~static_visitor() BOOST_NOEXCEPT { }
|
||
|
|
#endif
|
||
|
|
};
|
||
|
|
|
||
|
|
//////////////////////////////////////////////////////////////////////////
|
||
|
|
// metafunction is_static_visitor
|
||
|
|
//
|
||
|
|
// Value metafunction indicates whether the specified type derives from
|
||
|
|
// static_visitor<...>.
|
||
|
|
//
|
||
|
|
// NOTE #1: This metafunction does NOT check whether the specified type
|
||
|
|
// fulfills the requirements of the StaticVisitor concept.
|
||
|
|
//
|
||
|
|
// NOTE #2: This template never needs to be specialized!
|
||
|
|
//
|
||
|
|
|
||
|
|
namespace detail {
|
||
|
|
|
||
|
|
template <typename T>
|
||
|
|
struct is_static_visitor_impl
|
||
|
|
{
|
||
|
|
BOOST_STATIC_CONSTANT(bool, value =
|
||
|
|
(::boost::is_base_and_derived<
|
||
|
|
detail::is_static_visitor_tag,
|
||
|
|
T
|
||
|
|
>::value));
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace detail
|
||
|
|
|
||
|
|
template< typename T > struct is_static_visitor
|
||
|
|
: public ::boost::integral_constant<bool,(::boost::detail::is_static_visitor_impl<T>::value)>
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
BOOST_MPL_AUX_LAMBDA_SUPPORT(1,is_static_visitor,(T))
|
||
|
|
};
|
||
|
|
|
||
|
|
} // namespace boost
|
||
|
|
|
||
|
|
#endif // BOOST_VARIANT_STATIC_VISITOR_HPP
|