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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:45:59 +0000 |
commit | 19fcec84d8d7d21e796c7624e521b60d28ee21ed (patch) | |
tree | 42d26aa27d1e3f7c0b8bd3fd14e7d7082f5008dc /src/boost/libs/hana/example/eval_if.cpp | |
parent | Initial commit. (diff) | |
download | ceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.tar.xz ceph-19fcec84d8d7d21e796c7624e521b60d28ee21ed.zip |
Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/boost/libs/hana/example/eval_if.cpp')
-rw-r--r-- | src/boost/libs/hana/example/eval_if.cpp | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/eval_if.cpp b/src/boost/libs/hana/example/eval_if.cpp new file mode 100644 index 000000000..60aeef42a --- /dev/null +++ b/src/boost/libs/hana/example/eval_if.cpp @@ -0,0 +1,38 @@ +// 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/assert.hpp> +#include <boost/hana/config.hpp> +#include <boost/hana/equal.hpp> +#include <boost/hana/eval_if.hpp> +#include <boost/hana/lazy.hpp> +#include <boost/hana/traits.hpp> +#include <boost/hana/type.hpp> +namespace hana = boost::hana; + + +// eval_if with heterogeneous branches and a Constant condition +BOOST_HANA_CONSTEXPR_LAMBDA auto safe_make_unsigned = [](auto t) { + return hana::eval_if(hana::traits::is_integral(t), + hana::make_lazy(hana::traits::make_unsigned)(t), + hana::make_lazy(t) + ); +}; + +BOOST_HANA_CONSTANT_CHECK(safe_make_unsigned(hana::type_c<void>) == hana::type_c<void>); +BOOST_HANA_CONSTANT_CHECK(safe_make_unsigned(hana::type_c<int>) == hana::type_c<unsigned int>); + + +// eval_if with homogeneous branches and a constexpr or runtime condition +BOOST_HANA_CONSTEXPR_LAMBDA auto safe_divide = [](auto x, auto y) { + return hana::eval_if(y == 0, + [=](auto) { return 0; }, + [=](auto _) { return _(x) / y; } + ); +}; + +int main() { + BOOST_HANA_CONSTEXPR_CHECK(safe_divide(6, 3) == 2); + BOOST_HANA_CONSTEXPR_CHECK(safe_divide(6, 0) == 0); +} |