| // Boost enable_if library |
| |
| // Copyright 2003 (c) 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 Jarvi (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; |
| } |
| |