ceph/src/boost/libs/hana/test/if_/non_copyable.cpp

   1 // Copyright Louis Dionne 2013-2017
   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/bool.hpp>
   6 #include <boost/hana/eval_if.hpp>
   7 #include <boost/hana/fwd/not.hpp>
   8 #include <boost/hana/fwd/while.hpp>
   9 #include <boost/hana/if.hpp>
  10 namespace hana = boost::hana;
  11
  12
  13 // This test makes sure that if_ can be used with non-copyable branches.
  14
  15 template <bool Value>
  16 struct Boolean { };
  17
  18 namespace boost { namespace hana {
  19     template <bool Value>
  20     struct while_impl<Boolean<Value>> {
  21         // Not implemented
  22     };
  23
  24     template <bool Value>
  25     struct not_impl<Boolean<Value>> {
  26         // Not implemented
  27     };
  28
  29     template <bool Value>
  30     struct eval_if_impl<Boolean<Value>> {
  31         template <typename Cond, typename Then, typename Else>
  32         static constexpr decltype(auto) apply(Cond const&, Then&& t, Else&& e) {
  33             return hana::eval_if(hana::bool_c<Value>, static_cast<Then&&>(t),
  34                                                       static_cast<Else&&>(e));
  35         }
  36     };
  37 }}
  38
  39 template <int v>
  40 struct NonCopyable {
  41     static constexpr int value = v;
  42     NonCopyable() = default;
  43     NonCopyable(NonCopyable const&) = delete;
  44     NonCopyable(NonCopyable&&) = default;
  45
  46     NonCopyable& operator=(NonCopyable const&) = delete;
  47     NonCopyable& operator=(NonCopyable&&) = default;
  48 };
  49
  50 static_assert(hana::if_(Boolean<true>{}, NonCopyable<3>{}, NonCopyable<4>{}).value == 3, "");
  51 static_assert(hana::if_(Boolean<false>{}, NonCopyable<3>{}, NonCopyable<4>{}).value == 4, "");
  52
  53 int main() { }