eval_if.cpp

C++的一个好库。。。现在很流行

// 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.

// $Source: /cvsroot/boost/boost/libs/mpl/test/eval_if.cpp,v $
// $Date: 2004/09/02 15:41:35 $
// $Revision: 1.2 $

#include <boost/mpl/eval_if.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/mpl/identity.hpp>

#include <boost/mpl/aux_/test.hpp>

#include <boost/type_traits/is_same.hpp>

MPL_TEST_CASE()
{
    typedef eval_if< true_, identity<char>, identity<long> >::type t1;
    typedef eval_if_c< true, identity<char>, identity<long> >::type t2;
    typedef eval_if< false_, identity<char>, identity<long> >::type t3;
    typedef eval_if_c< false, identity<char>, identity<long> >::type t4;

    MPL_ASSERT(( is_same<t1,char> ));
    MPL_ASSERT(( is_same<t2,char> ));
    MPL_ASSERT(( is_same<t3,long> ));
    MPL_ASSERT(( is_same<t4,long> ));
}