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41 lines
1.1 KiB
C++
41 lines
1.1 KiB
C++
/*
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@copyright Louis Dionne 2014
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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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*/
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#include <boost/hana/maybe.hpp>
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#include <boost/hana/detail/constexpr.hpp>
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#include <boost/hana/detail/static_assert.hpp>
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#include <boost/hana/integral.hpp>
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using namespace boost::hana;
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BOOST_HANA_CONSTEXPR_LAMBDA auto inc = [](auto x) {
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return x + int_<1>;
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};
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int main() {
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// is_just
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BOOST_HANA_STATIC_ASSERT(is_just(just(1)));
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BOOST_HANA_STATIC_ASSERT(!is_just(nothing));
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// is_nothing
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BOOST_HANA_STATIC_ASSERT(!is_nothing(just(1)));
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BOOST_HANA_STATIC_ASSERT(is_nothing(nothing));
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// from_maybe
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BOOST_HANA_STATIC_ASSERT(from_maybe('d', nothing) == 'd');
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BOOST_HANA_STATIC_ASSERT(from_maybe('d', just(1)) == 1);
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BOOST_HANA_STATIC_ASSERT(from_maybe('d', just(int_<3>)) == int_<3>);
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// from_just
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BOOST_HANA_STATIC_ASSERT(from_just(just(1)) == 1);
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// from_just(nothing);
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// maybe
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BOOST_HANA_STATIC_ASSERT(maybe(int_<0>, inc, nothing) == int_<0>);
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BOOST_HANA_STATIC_ASSERT(maybe(int_<0>, inc, just(int_<1>)) == int_<2>);
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}
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