is_empty.cpp 1009 B

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  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. #include <boost/hana/assert.hpp>
  5. #include <boost/hana/experimental/view.hpp>
  6. #include <boost/hana/is_empty.hpp>
  7. #include <boost/hana/not.hpp>
  8. #include <support/seq.hpp>
  9. namespace hana = boost::hana;
  10. struct undefined { };
  11. int main() {
  12. auto container = ::seq;
  13. {
  14. auto xs = container();
  15. auto tr = hana::experimental::transformed(xs, undefined{});
  16. BOOST_HANA_CONSTANT_CHECK(hana::is_empty(tr));
  17. }
  18. {
  19. auto xs = container(undefined{});
  20. auto tr = hana::experimental::transformed(xs, undefined{});
  21. BOOST_HANA_CONSTANT_CHECK(hana::not_(hana::is_empty(tr)));
  22. }
  23. {
  24. auto xs = container(undefined{}, undefined{});
  25. auto tr = hana::experimental::transformed(xs, undefined{});
  26. BOOST_HANA_CONSTANT_CHECK(hana::not_(hana::is_empty(tr)));
  27. }
  28. }