ceph/src/boost/libs/hana/example/lazy/functor.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/eval.hpp>
   6 #include <boost/hana/functional/placeholder.hpp>
   7 #include <boost/hana/lazy.hpp>
   8 #include <boost/hana/transform.hpp>
   9 namespace hana = boost::hana;
  10 using hana::_;
  11
  12
  13 int main() {
  14     static_assert(hana::eval(hana::transform(hana::make_lazy(4 / _)(1), _ * 3)) == (4 / 1) * 3, "");
  15
  16     hana::transform(hana::make_lazy(4 / _)(0), _ * 3); // never evaluated
  17 }