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307d3d0ec8
- Split type class instances into separate files - Instances provided automatically by a type class are actually MCDs - Test each instance in a single file, not one file per method - Refactor the operator system to fix the ADL-related bug.
38 lines
907 B
C++
38 lines
907 B
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/functional/fix.hpp>
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#include <boost/hana/detail/assert.hpp>
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#include <boost/hana/detail/constexpr.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 fact = fix(
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[](auto fact, auto n) {
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return eval_if(n == int_<0>,
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always(int_<1>),
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[=](auto id) { return n * fact(n - id(int_<1>)); }
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);
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}
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);
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constexpr unsigned long long reference(unsigned long long n)
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{ return n == 0 ? 1 : n * reference(n - 1); }
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template <int n>
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constexpr void test() {
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BOOST_HANA_CONSTANT_ASSERT(fact(ullong<n>) == ullong<reference(n)>);
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test<n - 1>();
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}
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template <> constexpr void test<-1>() { }
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int main() {
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test<15>();
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}
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