ceph/src/boost/libs/hana/example/drop_back.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 #include <boost/hana/drop_back.hpp>
   7 #include <boost/hana/equal.hpp>
   8 #include <boost/hana/integral_constant.hpp>
   9 #include <boost/hana/tuple.hpp>
  10 namespace hana = boost::hana;
  11
  12
  13 constexpr auto xs = hana::make_tuple(0, '1', 2.0);
  14
  15 static_assert(hana::drop_back(xs, hana::size_c<0>) == xs, "");
  16 static_assert(hana::drop_back(xs, hana::size_c<1>) == hana::make_tuple(0, '1'), "");
  17 static_assert(hana::drop_back(xs, hana::size_c<2>) == hana::make_tuple(0), "");
  18 BOOST_HANA_CONSTANT_CHECK(hana::drop_back(xs, hana::size_c<3>) == hana::make_tuple());
  19 BOOST_HANA_CONSTANT_CHECK(hana::drop_back(xs, hana::size_c<4>) == hana::make_tuple());
  20
  21 static_assert(hana::drop_back(xs) == hana::make_tuple(0, '1'), "");
  22
  23 int main() { }