ceph/src/boost/libs/hana/test/assert/constant.cpp

   1 // Copyright Louis Dionne 2013-2016
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   4
   5 #include <boost/hana/assert.hpp>
   6
   7 #include <support/cnumeric.hpp>
   8 namespace hana = boost::hana;
   9
  10
  11 template <bool value>
  12 auto constant_bool() { return make_cnumeric<bool, value>(); }
  13
  14 template <bool value>
  15 constexpr auto constexpr_constant_bool() { return make_cnumeric<bool, value>(); }
  16
  17
  18 // Make sure it works at global scope
  19 BOOST_HANA_CONSTANT_ASSERT(constant_bool<true>());
  20 BOOST_HANA_CONSTANT_ASSERT_MSG(constant_bool<true>(), "message");
  21
  22 // Make sure it works at namespace scope
  23 namespace ns {
  24     BOOST_HANA_CONSTANT_ASSERT(constant_bool<true>());
  25     BOOST_HANA_CONSTANT_ASSERT_MSG(constant_bool<true>(), "message");
  26 }
  27
  28 // Make sure it works in a constexpr context
  29 constexpr bool constexpr_context() {
  30     BOOST_HANA_CONSTANT_ASSERT(constexpr_constant_bool<true>());
  31     BOOST_HANA_CONSTANT_ASSERT_MSG(constexpr_constant_bool<true>(), "message");
  32     return true;
  33 }
  34 static_assert(constexpr_context(), "");
  35
  36
  37 int main() {
  38     // Make sure it works at function scope
  39     BOOST_HANA_CONSTANT_ASSERT(constant_bool<true>());
  40     BOOST_HANA_CONSTANT_ASSERT_MSG(constant_bool<true>(), "message");
  41
  42     // Make sure it works inside a lambda
  43     auto lambda = []{
  44         BOOST_HANA_CONSTANT_ASSERT(constant_bool<true>());
  45         BOOST_HANA_CONSTANT_ASSERT_MSG(constant_bool<true>(), "message");
  46     };
  47     lambda();
  48
  49     // Make sure we can reference a local variable
  50     auto yes = constant_bool<true>();
  51     BOOST_HANA_CONSTANT_ASSERT(yes);
  52     BOOST_HANA_CONSTANT_ASSERT_MSG(yes, "message");
  53 }