| 1 | // Copyright Louis Dionne 2013-2022 |
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| 2 | // Distributed under the Boost Software License, Version 1.0. |
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| 3 | // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) |
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| 4 | |
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| 5 | #include <boost/hana/assert.hpp> |
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| 6 | #include <boost/hana/ext/std/integer_sequence.hpp> |
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| 7 | #include <boost/hana/unpack.hpp> |
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| 8 | |
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| 9 | #include <tuple> |
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| 10 | #include <utility> |
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| 11 | namespace hana = boost::hana; |
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| 12 | |
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| 13 | |
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| 14 | auto add = [](auto a, auto b, auto c) { return a + b + c; }; |
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| 15 | |
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| 16 | int main() { |
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| 17 | std::tuple<int, long, double> tuple{1, 2l, 3.3}; |
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| 18 | |
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| 19 | auto sum = hana::unpack(std::integer_sequence<int, 0, 1, 2>{}, [&](auto ...i) { |
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| 20 | // the `i`s are `std::integral_constant<int, ...>`s |
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| 21 | return add(std::get<decltype(i)::value>(tuple)...); |
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| 22 | }); |
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| 23 | |
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| 24 | BOOST_HANA_RUNTIME_CHECK(sum == 6.3); |
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| 25 | } |
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| 26 | |
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