1 // Copyright Louis Dionne 2013-2017
2 // Distributed under the Boost Software License, Version 1.0.
3 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
4
5 #ifndef TEST_SUPPORT_CNUMERIC_HPP
6 #define TEST_SUPPORT_CNUMERIC_HPP
7
8 #include <boost/hana/concept/integral_constant.hpp>
9 #include <boost/hana/core/when.hpp>
10 #include <boost/hana/fwd/core/to.hpp>
11 #include <boost/hana/fwd/equal.hpp>
12 #include <boost/hana/fwd/less.hpp>
13
14
15 template <typename T>
16 struct CNumeric { using value_type = T; };
17
18 template <typename T, T v>
19 struct cnumeric_t {
20 static constexpr T value = v;
21 using hana_tag = CNumeric<T>;
operator Tcnumeric_t22 constexpr operator T() const { return value; }
23 };
24
25 template <typename T, T v>
26 constexpr cnumeric_t<T, v> cnumeric{};
27
28 template <typename T, T v>
make_cnumeric()29 constexpr cnumeric_t<T, v> make_cnumeric() { return {}; }
30
31 namespace boost { namespace hana {
32 // Constant and IntegralConstant
33 template <typename T>
34 struct IntegralConstant<CNumeric<T>> {
35 static constexpr bool value = true;
36 };
37
38 template <typename T, typename C>
39 struct to_impl<CNumeric<T>, C, when<
40 hana::IntegralConstant<C>::value
41 >>
42 : embedding<is_embedded<typename C::value_type, T>::value>
43 {
44 template <typename N>
applyboost::hana::to_impl45 static constexpr auto apply(N const&)
46 { return cnumeric<T, N::value>; }
47 };
48
49 // Comparable
50 template <typename T, typename U>
51 struct equal_impl<CNumeric<T>, CNumeric<U>> {
52 template <typename X, typename Y>
applyboost::hana::equal_impl53 static constexpr auto apply(X const&, Y const&)
54 { return cnumeric<bool, X::value == Y::value>; }
55 };
56
57 // Orderable
58 template <typename T, typename U>
59 struct less_impl<CNumeric<T>, CNumeric<U>> {
60 template <typename X, typename Y>
applyboost::hana::less_impl61 static constexpr auto apply(X const&, Y const&)
62 { return cnumeric<bool, (X::value < Y::value)>; }
63 };
64 }} // end namespace boost::hana
65
66 #endif // !TEST_SUPPORT_CNUMERIC_HPP
67