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- // Copyright Louis Dionne 2013-2017
- // Distributed under the Boost Software License, Version 1.0.
- // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
- #include <boost/hana/any_of.hpp>
- #include <boost/hana/assert.hpp>
- #include <boost/hana/bool.hpp>
- #include <boost/hana/equal.hpp>
- #include <boost/hana/find_if.hpp>
- #include <boost/hana/fwd/at.hpp>
- #include <boost/hana/fwd/drop_front.hpp>
- #include <boost/hana/fwd/is_empty.hpp>
- #include <boost/hana/integral_constant.hpp>
- #include <boost/hana/optional.hpp>
- namespace hana = boost::hana;
- // A simple infinite Iterable.
- template <int i>
- struct counter { };
- namespace boost { namespace hana {
- template <int i>
- struct at_impl<counter<i>> {
- template <typename N>
- static constexpr auto apply(counter<i>, N const&) {
- return hana::int_c<i + N::value>;
- }
- };
- template <int i>
- struct drop_front_impl<counter<i>> {
- template <typename N>
- static constexpr auto apply(counter<i>, N) { return counter<i + N::value>{}; }
- };
- template <int i>
- struct is_empty_impl<counter<i>> {
- static constexpr auto apply(counter<i>) { return hana::false_c; }
- };
- }}
- int main() {
- // find_if and any_of should short-circuit and stop even though the
- // Iterable is infinite.
- BOOST_HANA_CONSTANT_CHECK(hana::any_of(counter<1>{}, hana::equal.to(hana::int_c<4>)));
- BOOST_HANA_CONSTANT_CHECK(hana::equal(
- hana::find_if(counter<1>{}, hana::equal.to(hana::int_c<4>)),
- hana::just(hana::int_c<4>)
- ));
- }
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