41 lines
1.0 KiB
C++
41 lines
1.0 KiB
C++
// Copyright Louis Dionne 2013-2017
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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#include <boost/hana/assert.hpp>
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#include <boost/hana/at.hpp>
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#include <boost/hana/fold_left.hpp>
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#include <boost/hana/tuple.hpp>
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namespace hana = boost::hana;
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//
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// Make sure that we can fold_left and take arguments by reference.
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//
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int main() {
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// with state
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{
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auto xs = hana::make_tuple(1, 2, 3);
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int state = 99;
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int& three = hana::fold_left(xs, state, [](int&, int& i) -> int& {
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return i;
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});
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BOOST_HANA_RUNTIME_CHECK(three == 3);
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three = 10;
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BOOST_HANA_RUNTIME_CHECK(hana::at_c<2>(xs) == 10);
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}
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// without state
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{
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auto xs = hana::make_tuple(1, 2, 3);
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int& three = hana::fold_left(xs, [](int&, int& i) -> int& {
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return i;
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});
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BOOST_HANA_RUNTIME_CHECK(three == 3);
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three = 10;
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BOOST_HANA_RUNTIME_CHECK(hana::at_c<2>(xs) == 10);
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}
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}
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