hana/test/assert/constant.cpp
2017-01-07 14:14:18 -08:00

54 lines
1.6 KiB
C++

// Copyright Louis Dionne 2013-2017
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
#include <boost/hana/assert.hpp>
#include <support/cnumeric.hpp>
namespace hana = boost::hana;
template <bool value>
auto constant_bool() { return make_cnumeric<bool, value>(); }
template <bool value>
constexpr auto constexpr_constant_bool() { return make_cnumeric<bool, value>(); }
// Make sure it works at global scope
BOOST_HANA_CONSTANT_ASSERT(constant_bool<true>());
BOOST_HANA_CONSTANT_ASSERT_MSG(constant_bool<true>(), "message");
// Make sure it works at namespace scope
namespace ns {
BOOST_HANA_CONSTANT_ASSERT(constant_bool<true>());
BOOST_HANA_CONSTANT_ASSERT_MSG(constant_bool<true>(), "message");
}
// Make sure it works in a constexpr context
constexpr bool constexpr_context() {
BOOST_HANA_CONSTANT_ASSERT(constexpr_constant_bool<true>());
BOOST_HANA_CONSTANT_ASSERT_MSG(constexpr_constant_bool<true>(), "message");
return true;
}
static_assert(constexpr_context(), "");
int main() {
// Make sure it works at function scope
BOOST_HANA_CONSTANT_ASSERT(constant_bool<true>());
BOOST_HANA_CONSTANT_ASSERT_MSG(constant_bool<true>(), "message");
// Make sure it works inside a lambda
auto lambda = []{
BOOST_HANA_CONSTANT_ASSERT(constant_bool<true>());
BOOST_HANA_CONSTANT_ASSERT_MSG(constant_bool<true>(), "message");
};
lambda();
// Make sure we can reference a local variable
auto yes = constant_bool<true>();
BOOST_HANA_CONSTANT_ASSERT(yes);
BOOST_HANA_CONSTANT_ASSERT_MSG(yes, "message");
}