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61 lines
2.3 KiB
C++
61 lines
2.3 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/list.hpp>
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#include <boost/hana/comparable.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/functional.hpp>
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#include <boost/hana/integral.hpp>
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#include <boost/hana/type.hpp>
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using namespace boost::hana;
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struct EqClass;
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template <int equivalence_class> struct X { using hana_datatype = EqClass; };
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template <int equivalence_class> struct Y { using hana_datatype = EqClass; };
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template <int equivalence_class> constexpr X<equivalence_class> x{};
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template <int equivalence_class> constexpr Y<equivalence_class> y{};
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namespace boost { namespace hana {
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template <>
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struct Comparable::instance<EqClass, EqClass> : Comparable::equal_mcd {
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template <typename T, typename U>
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static constexpr auto equal_impl(T, U)
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{ return type<T> == type<U>; }
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};
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}}
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constexpr struct _predicate {
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template <int i, int j, template <int> class X, template <int> class Y>
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constexpr auto operator()(X<i>, Y<j>) const
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{ return bool_<(i < j)>; }
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} pred{};
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int main() {
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BOOST_HANA_CONSTEXPR_LAMBDA auto check = [](auto sorted_list) {
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auto perms = fmap(partial(sort_by, pred), permutations(sorted_list));
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BOOST_HANA_STATIC_ASSERT(all(_ == sorted_list, perms));
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};
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check(list());
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check(list(x<1>));
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check(list(x<1>, x<2>));
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check(list(x<1>, x<2>, x<3>));
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// check stability
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BOOST_HANA_STATIC_ASSERT(sort_by(pred, list(x<1>, y<1>)) == list(x<1>, y<1>));
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BOOST_HANA_STATIC_ASSERT(sort_by(pred, list(y<1>, x<1>)) == list(y<1>, x<1>));
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BOOST_HANA_STATIC_ASSERT(sort_by(pred, list(x<1>, y<1>, x<2>, y<2>)) == list(x<1>, y<1>, x<2>, y<2>));
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BOOST_HANA_STATIC_ASSERT(sort_by(pred, list(x<1>, x<2>, y<1>, y<2>)) == list(x<1>, y<1>, x<2>, y<2>));
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BOOST_HANA_STATIC_ASSERT(sort_by(pred, list(y<1>, x<1>, x<2>, y<2>)) == list(y<1>, x<1>, x<2>, y<2>));
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BOOST_HANA_STATIC_ASSERT(sort_by(pred, list(x<2>, y<1>, y<2>, x<1>)) == list(y<1>, x<1>, x<2>, y<2>));
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BOOST_HANA_STATIC_ASSERT(sort_by(pred, list(x<1>, x<3>, y<1>, x<2>, y<3>)) == list(x<1>, y<1>, x<2>, x<3>, y<3>));
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}
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