| 1 | // Copyright Louis Dionne 2013-2022 |
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| 2 | // Distributed under the Boost Software License, Version 1.0. |
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| 3 | // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) |
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| 4 | |
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| 5 | #include <boost/hana/assert.hpp> |
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| 6 | #include <boost/hana/concept/metafunction.hpp> |
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| 7 | #include <boost/hana/equal.hpp> |
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| 8 | #include <boost/hana/not.hpp> |
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| 9 | #include <boost/hana/type.hpp> |
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| 10 | |
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| 11 | #include <type_traits> |
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| 12 | namespace hana = boost::hana; |
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| 13 | |
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| 14 | |
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| 15 | struct x1; struct x2; struct x3; |
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| 16 | struct y1 { }; struct y2 { }; struct y3 { }; |
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| 17 | template <typename ...> struct f; |
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| 18 | |
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| 19 | BOOST_HANA_CONSTANT_CHECK(hana::equal( |
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| 20 | hana::template_<f>(), |
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| 21 | hana::type_c<f<>> |
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| 22 | )); |
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| 23 | BOOST_HANA_CONSTANT_CHECK(hana::equal( |
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| 24 | hana::template_<f>(hana::type_c<x1>), |
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| 25 | hana::type_c<f<x1>> |
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| 26 | )); |
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| 27 | BOOST_HANA_CONSTANT_CHECK(hana::equal( |
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| 28 | hana::template_<f>(hana::type_c<x1>, hana::type_c<x2>), |
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| 29 | hana::type_c<f<x1, x2>> |
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| 30 | )); |
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| 31 | BOOST_HANA_CONSTANT_CHECK(hana::equal( |
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| 32 | hana::template_<f>(hana::type_c<x1>, hana::type_c<x2>, hana::type_c<x3>), |
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| 33 | hana::type_c<f<x1, x2, x3>> |
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| 34 | )); |
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| 35 | |
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| 36 | using F = decltype(hana::template_<f>); |
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| 37 | static_assert(std::is_same<F::apply<>::type, f<>>{}, "" ); |
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| 38 | static_assert(std::is_same<F::apply<x1>::type, f<x1>>{}, "" ); |
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| 39 | static_assert(std::is_same<F::apply<x1, x2>::type, f<x1, x2>>{}, "" ); |
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| 40 | static_assert(std::is_same<F::apply<x1, x2, x3>::type, f<x1, x2, x3>>{}, "" ); |
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| 41 | |
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| 42 | // Make sure we model the Metafunction concept |
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| 43 | static_assert(hana::Metafunction<decltype(hana::template_<f>)>::value, "" ); |
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| 44 | static_assert(hana::Metafunction<decltype(hana::template_<f>)&>::value, "" ); |
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| 45 | |
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| 46 | // Make sure we can use aliases |
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| 47 | template <typename T> using alias = T; |
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| 48 | static_assert(hana::template_<alias>(hana::type_c<x1>) == hana::type_c<x1>, "" ); |
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| 49 | |
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| 50 | // Make sure template_ is SFINAE-friendly |
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| 51 | template <typename T> struct unary; |
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| 52 | BOOST_HANA_CONSTANT_CHECK(hana::not_( |
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| 53 | hana::is_valid(hana::template_<unary>)(hana::type_c<void>, hana::type_c<void>) |
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| 54 | )); |
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| 55 | |
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| 56 | // Make sure we don't read from a non-constexpr variable |
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| 57 | int main() { |
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| 58 | auto t = hana::type_c<x1>; |
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| 59 | constexpr auto r = hana::template_<f>(t); |
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| 60 | (void)r; |
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| 61 | } |
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| 62 | |
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