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Added enable_if library

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[SVN r21090]
This commit is contained in:
Jaakko Järvi
2003-12-02 21:41:15 +00:00
parent abcab174a5
commit 929517d6d7
13 changed files with 993 additions and 0 deletions
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enable_if_lazy_test.cpp Normal file
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// Boost enable_if library
// Copyright 2003 <20> The Trustees of Indiana University.
// Use, modification, and distribution is subject to 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)
// Authors: Jaakko J<>rvi (jajarvi at osl.iu.edu)
// Jeremiah Willcock (jewillco at osl.iu.edu)
// Andrew Lumsdaine (lums at osl.iu.edu)
// Testing all variations of lazy_enable_if.
#include <boost/test/minimal.hpp>
#include <boost/mpl/not.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits/is_same.hpp>
using boost::lazy_enable_if;
using boost::lazy_disable_if;
using boost::lazy_enable_if_c;
using boost::lazy_disable_if_c;
template <class T>
struct is_int_or_double {
BOOST_STATIC_CONSTANT(bool,
value = (boost::is_same<T, int>::value ||
boost::is_same<T, double>::value));
};
template <class T>
struct some_traits {
typedef typename T::does_not_exist type;
};
template <>
struct some_traits<int> {
typedef bool type;
};
template <>
struct some_traits<double> {
typedef bool type;
};
template <class T>
struct make_bool {
typedef bool type;
};
template <>
struct make_bool<int> {};
template <>
struct make_bool<double> {};
namespace A {
template<class T>
typename lazy_enable_if<is_int_or_double<T>, some_traits<T> >::type
foo(T t) { return true; }
template<class T>
typename lazy_enable_if_c<is_int_or_double<T>::value, some_traits<T> >::type
foo2(T t) { return true; }
}
namespace B {
template<class T>
typename lazy_disable_if<is_int_or_double<T>, make_bool<T> >::type
foo(T t) { return false; }
template<class T>
typename lazy_disable_if_c<is_int_or_double<T>::value, make_bool<T> >::type
foo2(T t) { return false; }
}
int test_main(int, char*[])
{
using namespace A;
using namespace B;
BOOST_CHECK(foo(1));
BOOST_CHECK(foo(1.0));
BOOST_CHECK(!foo("1"));
BOOST_CHECK(!foo(static_cast<void*>(0)));
BOOST_CHECK(foo2(1));
BOOST_CHECK(foo2(1.0));
BOOST_CHECK(!foo2("1"));
BOOST_CHECK(!foo2(static_cast<void*>(0)));
return 0;
}