ceph/src/boost/libs/hana/test/fold_right/ref.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/assert.hpp>
   6 #include <boost/hana/at.hpp>
   7 #include <boost/hana/fold_right.hpp>
   8 #include <boost/hana/tuple.hpp>
   9 namespace hana = boost::hana;
  10
  11 //
  12 // Make sure that we can fold_right and take arguments by reference.
  13 //
  14
  15 int main() {
  16     // with state
  17     {
  18         auto xs = hana::make_tuple(1, 2, 3);
  19         int state = 99;
  20
  21         int& one = hana::fold_right(xs, state, [](int& i, int&) -> int& {
  22             return i;
  23         });
  24         BOOST_HANA_RUNTIME_CHECK(one == 1);
  25         one = 10;
  26         BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(xs) == 10);
  27     }
  28
  29     // without state
  30     {
  31         auto xs = hana::make_tuple(1, 2, 3);
  32         int& one = hana::fold_right(xs, [](int& i, int&) -> int& {
  33             return i;
  34         });
  35         BOOST_HANA_RUNTIME_CHECK(one == 1);
  36         one = 10;
  37         BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(xs) == 10);
  38     }
  39 }