c353ccdd9b
When C++17 is supported, constexpr lambdas can be used and CONSTEXPR_ASSERT turns into an actual static_assert. This is not unconditionally enabled for now because Clang does not support constexpr lambdas with captures (!).
19 lines
555 B
C++
19 lines
555 B
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/config.hpp>
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#include <boost/hana/functional/fix.hpp>
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namespace hana = boost::hana;
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BOOST_HANA_CONSTEXPR_STATELESS_LAMBDA auto factorial = hana::fix([](auto fact, auto n) -> int {
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if (n == 0) return 1;
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else return n * fact(n - 1);
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});
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int main() {
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BOOST_HANA_CONSTEXPR_CHECK(factorial(5) == 120);
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}
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