| 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/at.hpp> |
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| 7 | #include <boost/hana/fold_right.hpp> |
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| 8 | #include <boost/hana/tuple.hpp> |
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| 9 | namespace hana = boost::hana; |
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| 10 | |
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| 11 | // |
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| 12 | // Make sure that we can fold_right and take arguments by reference. |
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| 13 | // |
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| 14 | |
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| 15 | int main() { |
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| 16 | // with state |
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| 17 | { |
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| 18 | auto xs = hana::make_tuple(1, 2, 3); |
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| 19 | int state = 99; |
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| 20 | |
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| 21 | int& one = hana::fold_right(xs, state, [](int& i, int&) -> int& { |
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| 22 | return i; |
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| 23 | }); |
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| 24 | BOOST_HANA_RUNTIME_CHECK(one == 1); |
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| 25 | one = 10; |
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| 26 | BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(xs) == 10); |
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| 27 | } |
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| 28 | |
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| 29 | // without state |
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| 30 | { |
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| 31 | auto xs = hana::make_tuple(1, 2, 3); |
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| 32 | int& one = hana::fold_right(xs, [](int& i, int&) -> int& { |
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| 33 | return i; |
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| 34 | }); |
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| 35 | BOOST_HANA_RUNTIME_CHECK(one == 1); |
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| 36 | one = 10; |
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| 37 | BOOST_HANA_RUNTIME_CHECK(hana::at_c<0>(xs) == 10); |
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| 38 | } |
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| 39 | } |
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| 40 | |
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