ceph/src/boost/libs/hana/example/transform.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/optional.hpp>
   8 #include <boost/hana/transform.hpp>
   9 #include <boost/hana/tuple.hpp>
  10 #include <boost/hana/type.hpp>
  11
  12 #include <sstream>
  13 #include <string>
  14 #include <type_traits>
  15 namespace hana = boost::hana;
  16 using namespace std::literals;
  17
  18
  19 auto to_string = [](auto x) {
  20     std::ostringstream ss;
  21     ss << x;
  22     return ss.str();
  23 };
  24
  25 int main() {
  26     BOOST_HANA_RUNTIME_CHECK(
  27         hana::transform(hana::make_tuple(1, '2', "345", std::string{"67"}), to_string)
  28                 ==
  29         hana::make_tuple("1", "2", "345", "67")
  30     );
  31
  32     BOOST_HANA_CONSTANT_CHECK(hana::transform(hana::nothing, to_string) == hana::nothing);
  33     BOOST_HANA_RUNTIME_CHECK(hana::transform(hana::just(123), to_string) == hana::just("123"s));
  34
  35     BOOST_HANA_CONSTANT_CHECK(
  36         hana::transform(hana::tuple_t<void, int(), char[10]>, hana::template_<std::add_pointer_t>)
  37                 ==
  38         hana::tuple_t<void*, int(*)(), char(*)[10]>
  39     );
  40 }