| 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/fold_right.hpp> |
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| 7 | #include <boost/hana/tuple.hpp> |
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| 8 | |
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| 9 | #include <sstream> |
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| 10 | #include <string> |
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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 to_string = [](auto x) { |
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| 15 | std::ostringstream ss; |
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| 16 | ss << x; |
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| 17 | return ss.str(); |
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| 18 | }; |
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| 19 | |
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| 20 | int main() { |
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| 21 | auto f = [=](auto element, std::string s) { |
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| 22 | return "f(" + to_string(element) + ", " + s + ")" ; |
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| 23 | }; |
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| 24 | |
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| 25 | // with an initial state |
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| 26 | BOOST_HANA_RUNTIME_CHECK( |
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| 27 | hana::fold_right(hana::make_tuple(1, '2', 3.0, 4), "5" , f) |
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| 28 | == |
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| 29 | "f(1, f(2, f(3, f(4, 5))))" |
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| 30 | ); |
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| 31 | |
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| 32 | // without initial state |
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| 33 | BOOST_HANA_RUNTIME_CHECK( |
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| 34 | hana::fold_right(hana::make_tuple(1, '2', 3.0, 4, "5" ), f) |
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| 35 | == |
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| 36 | "f(1, f(2, f(3, f(4, 5))))" |
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| 37 | ); |
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| 38 | } |
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| 39 | |
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