#ifndef BOOST_MPL_IF_HPP_INCLUDED | |
#define BOOST_MPL_IF_HPP_INCLUDED | |
// Copyright Aleksey Gurtovoy 2000-2004 | |
// | |
// 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) | |
// | |
// See http://www.boost.org/libs/mpl for documentation. | |
// $Id: if.hpp 49267 2008-10-11 06:19:02Z agurtovoy $ | |
// $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $ | |
// $Revision: 49267 $ | |
#include <boost/mpl/aux_/value_wknd.hpp> | |
#include <boost/mpl/aux_/static_cast.hpp> | |
#include <boost/mpl/aux_/na_spec.hpp> | |
#include <boost/mpl/aux_/lambda_support.hpp> | |
#include <boost/mpl/aux_/config/integral.hpp> | |
#include <boost/mpl/aux_/config/ctps.hpp> | |
#include <boost/mpl/aux_/config/workaround.hpp> | |
namespace boost { namespace mpl { | |
#if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) | |
template< | |
bool C | |
, typename T1 | |
, typename T2 | |
> | |
struct if_c | |
{ | |
typedef T1 type; | |
}; | |
template< | |
typename T1 | |
, typename T2 | |
> | |
struct if_c<false,T1,T2> | |
{ | |
typedef T2 type; | |
}; | |
// agurt, 05/sep/04: nondescriptive parameter names for the sake of DigitalMars | |
// (and possibly MWCW < 8.0); see http://article.gmane.org/gmane.comp.lib.boost.devel/108959 | |
template< | |
typename BOOST_MPL_AUX_NA_PARAM(T1) | |
, typename BOOST_MPL_AUX_NA_PARAM(T2) | |
, typename BOOST_MPL_AUX_NA_PARAM(T3) | |
> | |
struct if_ | |
{ | |
private: | |
// agurt, 02/jan/03: two-step 'type' definition for the sake of aCC | |
typedef if_c< | |
#if defined(BOOST_MPL_CFG_BCC_INTEGRAL_CONSTANTS) | |
BOOST_MPL_AUX_VALUE_WKND(T1)::value | |
#else | |
BOOST_MPL_AUX_STATIC_CAST(bool, BOOST_MPL_AUX_VALUE_WKND(T1)::value) | |
#endif | |
, T2 | |
, T3 | |
> almost_type_; | |
public: | |
typedef typename almost_type_::type type; | |
BOOST_MPL_AUX_LAMBDA_SUPPORT(3,if_,(T1,T2,T3)) | |
}; | |
#else | |
// no partial class template specialization | |
namespace aux { | |
template< bool C > | |
struct if_impl | |
{ | |
template< typename T1, typename T2 > struct result_ | |
{ | |
typedef T1 type; | |
}; | |
}; | |
template<> | |
struct if_impl<false> | |
{ | |
template< typename T1, typename T2 > struct result_ | |
{ | |
typedef T2 type; | |
}; | |
}; | |
} // namespace aux | |
template< | |
bool C_ | |
, typename T1 | |
, typename T2 | |
> | |
struct if_c | |
{ | |
typedef typename aux::if_impl< C_ > | |
::template result_<T1,T2>::type type; | |
}; | |
// (almost) copy & paste in order to save one more | |
// recursively nested template instantiation to user | |
template< | |
typename BOOST_MPL_AUX_NA_PARAM(C_) | |
, typename BOOST_MPL_AUX_NA_PARAM(T1) | |
, typename BOOST_MPL_AUX_NA_PARAM(T2) | |
> | |
struct if_ | |
{ | |
enum { msvc_wknd_ = BOOST_MPL_AUX_MSVC_VALUE_WKND(C_)::value }; | |
typedef typename aux::if_impl< BOOST_MPL_AUX_STATIC_CAST(bool, msvc_wknd_) > | |
::template result_<T1,T2>::type type; | |
BOOST_MPL_AUX_LAMBDA_SUPPORT(3,if_,(C_,T1,T2)) | |
}; | |
#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION | |
BOOST_MPL_AUX_NA_SPEC(3, if_) | |
}} | |
#endif // BOOST_MPL_IF_HPP_INCLUDED |