ceph/src/boost/libs/hana/example/count_if.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/count_if.hpp>
   7 #include <boost/hana/equal.hpp>
   8 #include <boost/hana/ext/std/integral_constant.hpp>
   9 #include <boost/hana/integral_constant.hpp>
  10 #include <boost/hana/mod.hpp>
  11 #include <boost/hana/not_equal.hpp>
  12 #include <boost/hana/tuple.hpp>
  13 #include <boost/hana/type.hpp>
  14
  15 #include <type_traits>
  16 namespace hana = boost::hana;
  17 using namespace hana::literals;
  18
  19
  20 auto is_odd = [](auto x) {
  21     return x % 2_c != 0_c;
  22 };
  23
  24 int main() {
  25     constexpr auto ints = hana::tuple_c<int, 1, 2, 3>;
  26     BOOST_HANA_CONSTANT_CHECK(hana::count_if(ints, is_odd) == hana::size_c<2>);
  27
  28     constexpr auto types = hana::tuple_t<int, char, long, short, char, double>;
  29     BOOST_HANA_CONSTANT_CHECK(hana::count_if(types, hana::trait<std::is_floating_point>) == hana::size_c<1>);
  30     BOOST_HANA_CONSTANT_CHECK(hana::count_if(types, hana::equal.to(hana::type_c<char>)) == hana::size_c<2>);
  31     BOOST_HANA_CONSTANT_CHECK(hana::count_if(types, hana::equal.to(hana::type_c<void>)) == hana::size_c<0>);
  32 }