span.cpp 1.3 KB

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