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Diffstat (limited to 'src/boost/libs/hana/test/type/metafunction.cpp')
-rw-r--r-- | src/boost/libs/hana/test/type/metafunction.cpp | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/src/boost/libs/hana/test/type/metafunction.cpp b/src/boost/libs/hana/test/type/metafunction.cpp new file mode 100644 index 000000000..aa52c1f38 --- /dev/null +++ b/src/boost/libs/hana/test/type/metafunction.cpp @@ -0,0 +1,72 @@ +// Copyright Louis Dionne 2013-2017 +// Distributed under the Boost Software License, Version 1.0. +// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) + +#include <boost/hana/assert.hpp> +#include <boost/hana/concept/metafunction.hpp> +#include <boost/hana/equal.hpp> +#include <boost/hana/not.hpp> +#include <boost/hana/type.hpp> + +#include <type_traits> +namespace hana = boost::hana; + + +struct x1; struct x2; struct x3; +struct y1 { }; struct y2 { }; struct y3 { }; +template <typename ...> struct f { struct type; }; + +template <typename F, typename ...T> +constexpr auto valid_call(F f, T ...t) -> decltype(((void)f(t...)), true) +{ return true; } +constexpr auto valid_call(...) +{ return false; } + +BOOST_HANA_CONSTANT_CHECK(hana::equal( + hana::metafunction<f>(), + hana::type_c<f<>::type> +)); + +BOOST_HANA_CONSTANT_CHECK(hana::equal( + hana::metafunction<f>(hana::type_c<x1>), + hana::type_c<f<x1>::type> +)); + +BOOST_HANA_CONSTANT_CHECK(hana::equal( + hana::metafunction<f>(hana::type_c<x1>, hana::type_c<x2>), + hana::type_c<f<x1, x2>::type> +)); + +BOOST_HANA_CONSTANT_CHECK(hana::equal( + hana::metafunction<f>(hana::type_c<x1>, hana::type_c<x2>, hana::type_c<x3>), + hana::type_c<f<x1, x2, x3>::type> +)); + +using F = decltype(hana::metafunction<f>); +static_assert(std::is_same<F::apply<>, f<>>::value, ""); +static_assert(std::is_same<F::apply<x1>, f<x1>>::value, ""); +static_assert(std::is_same<F::apply<x1, x2>, f<x1, x2>>::value, ""); +static_assert(std::is_same<F::apply<x1, x2, x3>, f<x1, x2, x3>>::value, ""); + +// Make sure we're SFINAE-friendly +template <typename ...T> struct no_type { }; +static_assert(!valid_call(hana::metafunction<no_type>), ""); +static_assert(!valid_call(hana::metafunction<no_type>, hana::type_c<x1>), ""); + +// Make sure we model the Metafunction concept +static_assert(hana::Metafunction<decltype(hana::metafunction<f>)>::value, ""); +static_assert(hana::Metafunction<decltype(hana::metafunction<f>)&>::value, ""); + +// Make sure metafunction is SFINAE-friendly +template <typename T> struct not_a_metafunction { }; +BOOST_HANA_CONSTANT_CHECK(hana::not_( + hana::is_valid(hana::metafunction<not_a_metafunction>)(hana::type_c<void>) +)); + + +// Make sure we don't read from a non-constexpr variable +int main() { + auto t = hana::type_c<x1>; + constexpr auto r = hana::metafunction<f>(t); + (void)r; +} |