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Diffstat (limited to 'src/boost/libs/hana/example/core/convert/embedding.cpp')
-rw-r--r-- | src/boost/libs/hana/example/core/convert/embedding.cpp | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/boost/libs/hana/example/core/convert/embedding.cpp b/src/boost/libs/hana/example/core/convert/embedding.cpp new file mode 100644 index 000000000..618637a2b --- /dev/null +++ b/src/boost/libs/hana/example/core/convert/embedding.cpp @@ -0,0 +1,36 @@ +// 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/core/to.hpp> +#include <boost/hana/core/when.hpp> + +#include <vector> +namespace hana = boost::hana; + + +namespace boost { namespace hana { + template <typename To, typename From> + struct to_impl<std::vector<To>, std::vector<From>, + when<is_convertible<From, To>::value>> + : embedding<is_embedded<From, To>::value> + { + static std::vector<To> apply(std::vector<From> const& xs) { + std::vector<To> result; + for (auto const& x: xs) + result.push_back(to<To>(x)); + return result; + } + }; +}} + +int main() { + BOOST_HANA_RUNTIME_CHECK( + hana::to<std::vector<int>>(std::vector<float>{1.1, 2.2, 3.3}) + == + std::vector<int>{1, 2, 3} + ); + + static_assert(!hana::is_embedded<std::vector<float>, std::vector<int>>{}, ""); +} |