ceph/src/boost/libs/hana/example/comparing.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/comparing.hpp>
   6 #include <boost/hana/equal.hpp>
   7 #include <boost/hana/group.hpp>
   8 #include <boost/hana/length.hpp>
   9 #include <boost/hana/range.hpp>
  10 #include <boost/hana/tuple.hpp>
  11 namespace hana = boost::hana;
  12
  13
  14 int main() {
  15     constexpr auto sequences = hana::make_tuple(
  16         hana::make_tuple(1, 2, 3),
  17         hana::make_tuple('x', 'y', 'z'),
  18         hana::range_c<long, 0, 1>,
  19         hana::tuple_t<char, int>,
  20         hana::range_c<int, 0, 2>,
  21         hana::make_tuple(123.4, nullptr)
  22     );
  23
  24     constexpr auto grouped = hana::group.by(hana::comparing(hana::length), sequences);
  25
  26     static_assert(grouped == hana::make_tuple(
  27         hana::make_tuple(
  28             hana::make_tuple(1, 2, 3),
  29             hana::make_tuple('x', 'y', 'z')
  30         ),
  31         hana::make_tuple(
  32             hana::range_c<long, 0, 1>
  33         ),
  34         hana::make_tuple(
  35             hana::tuple_t<char, int>,
  36             hana::range_c<int, 0, 2>,
  37             hana::make_tuple(123.4, nullptr)
  38         )
  39     ), "");
  40 }