ceph/src/boost/libs/hana/example/span.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/equal.hpp>
   7 #include <boost/hana/integral_constant.hpp>
   8 #include <boost/hana/less.hpp>
   9 #include <boost/hana/pair.hpp>
  10 #include <boost/hana/span.hpp>
  11 #include <boost/hana/tuple.hpp>
  12 namespace hana = boost::hana;
  13
  14
  15 constexpr auto xs = hana::make_tuple(hana::int_c<1>, hana::int_c<2>, hana::int_c<3>, hana::int_c<4>);
  16
  17 BOOST_HANA_CONSTANT_CHECK(
  18     hana::span(xs, hana::less.than(hana::int_c<3>))
  19     ==
  20     hana::make_pair(hana::make_tuple(hana::int_c<1>, hana::int_c<2>),
  21                     hana::make_tuple(hana::int_c<3>, hana::int_c<4>))
  22 );
  23
  24 BOOST_HANA_CONSTANT_CHECK(
  25     hana::span(xs, hana::less.than(hana::int_c<0>))
  26     ==
  27     hana::make_pair(hana::make_tuple(), xs)
  28 );
  29
  30 BOOST_HANA_CONSTANT_CHECK(
  31     hana::span(xs, hana::less.than(hana::int_c<5>))
  32     ==
  33     hana::make_pair(xs, hana::make_tuple())
  34 );
  35
  36 // span.by is syntactic sugar
  37 BOOST_HANA_CONSTANT_CHECK(
  38     hana::span.by(hana::less.than(hana::int_c<3>), xs)
  39     ==
  40     hana::make_pair(hana::make_tuple(hana::int_c<1>, hana::int_c<2>),
  41                     hana::make_tuple(hana::int_c<3>, hana::int_c<4>))
  42 );
  43
  44 int main() { }