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- // 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)
- #ifndef TEST_SUPPORT_CNUMERIC_HPP
- #define TEST_SUPPORT_CNUMERIC_HPP
- #include <boost/hana/concept/integral_constant.hpp>
- #include <boost/hana/core/when.hpp>
- #include <boost/hana/fwd/core/to.hpp>
- #include <boost/hana/fwd/equal.hpp>
- #include <boost/hana/fwd/less.hpp>
- template <typename T>
- struct CNumeric { using value_type = T; };
- template <typename T, T v>
- struct cnumeric_t {
- static constexpr T value = v;
- using hana_tag = CNumeric<T>;
- constexpr operator T() const { return value; }
- };
- template <typename T, T v>
- constexpr cnumeric_t<T, v> cnumeric{};
- template <typename T, T v>
- constexpr cnumeric_t<T, v> make_cnumeric() { return {}; }
- namespace boost { namespace hana {
- // Constant and IntegralConstant
- template <typename T>
- struct IntegralConstant<CNumeric<T>> {
- static constexpr bool value = true;
- };
- template <typename T, typename C>
- struct to_impl<CNumeric<T>, C, when<
- hana::IntegralConstant<C>::value
- >>
- : embedding<is_embedded<typename C::value_type, T>::value>
- {
- template <typename N>
- static constexpr auto apply(N const&)
- { return cnumeric<T, N::value>; }
- };
- // Comparable
- template <typename T, typename U>
- struct equal_impl<CNumeric<T>, CNumeric<U>> {
- template <typename X, typename Y>
- static constexpr auto apply(X const&, Y const&)
- { return cnumeric<bool, X::value == Y::value>; }
- };
- // Orderable
- template <typename T, typename U>
- struct less_impl<CNumeric<T>, CNumeric<U>> {
- template <typename X, typename Y>
- static constexpr auto apply(X const&, Y const&)
- { return cnumeric<bool, (X::value < Y::value)>; }
- };
- }} // end namespace boost::hana
- #endif // !TEST_SUPPORT_CNUMERIC_HPP
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