108 lines
3.8 KiB
C++
108 lines
3.8 KiB
C++
|
/*!
|
||
|
|
@file
|
||
|
|
Defines `boost::hana::mult`.
|
||
|
|
|
||
|
|
@copyright Louis Dionne 2013-2016
|
||
|
|
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 BOOST_HANA_MULT_HPP
|
||
|
|
#define BOOST_HANA_MULT_HPP
|
||
|
|
|
||
|
|
#include <boost/hana/fwd/mult.hpp>
|
||
|
|
|
||
|
|
#include <boost/hana/concept/constant.hpp>
|
||
|
|
#include <boost/hana/concept/ring.hpp>
|
||
|
|
#include <boost/hana/config.hpp>
|
||
|
|
#include <boost/hana/core/to.hpp>
|
||
|
|
#include <boost/hana/core/dispatch.hpp>
|
||
|
|
#include <boost/hana/detail/canonical_constant.hpp>
|
||
|
|
#include <boost/hana/detail/has_common_embedding.hpp>
|
||
|
|
#include <boost/hana/value.hpp>
|
||
|
|
|
||
|
|
#include <type_traits>
|
||
|
|
|
||
|
|
|
||
|
|
BOOST_HANA_NAMESPACE_BEGIN
|
||
|
|
//! @cond
|
||
|
|
template <typename X, typename Y>
|
||
|
|
constexpr decltype(auto) mult_t::operator()(X&& x, Y&& y) const {
|
||
|
|
using T = typename hana::tag_of<X>::type;
|
||
|
|
using U = typename hana::tag_of<Y>::type;
|
||
|
|
using Mult = BOOST_HANA_DISPATCH_IF(decltype(mult_impl<T, U>{}),
|
||
|
|
hana::Ring<T>::value &&
|
||
|
|
hana::Ring<U>::value &&
|
||
|
|
!is_default<mult_impl<T, U>>::value
|
||
|
|
);
|
||
|
|
|
||
|
|
#ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS
|
||
|
|
static_assert(hana::Ring<T>::value,
|
||
|
|
"hana::mult(x, y) requires 'x' to be in a Ring");
|
||
|
|
|
||
|
|
static_assert(hana::Ring<U>::value,
|
||
|
|
"hana::mult(x, y) requires 'y' to be in a Ring");
|
||
|
|
|
||
|
|
static_assert(!is_default<mult_impl<T, U>>::value,
|
||
|
|
"hana::mult(x, y) requires 'x' and 'y' to be embeddable "
|
||
|
|
"in a common Ring");
|
||
|
|
#endif
|
||
|
|
|
||
|
|
return Mult::apply(static_cast<X&&>(x), static_cast<Y&&>(y));
|
||
|
|
}
|
||
|
|
//! @endcond
|
||
|
|
|
||
|
|
template <typename T, typename U, bool condition>
|
||
|
|
struct mult_impl<T, U, when<condition>> : default_ {
|
||
|
|
template <typename ...Args>
|
||
|
|
static constexpr auto apply(Args&& ...) = delete;
|
||
|
|
};
|
||
|
|
|
||
|
|
// Cross-type overload
|
||
|
|
template <typename T, typename U>
|
||
|
|
struct mult_impl<T, U, when<
|
||
|
|
detail::has_nontrivial_common_embedding<Ring, T, U>::value
|
||
|
|
>> {
|
||
|
|
using C = typename common<T, U>::type;
|
||
|
|
template <typename X, typename Y>
|
||
|
|
static constexpr decltype(auto) apply(X&& x, Y&& y) {
|
||
|
|
return hana::mult(hana::to<C>(static_cast<X&&>(x)),
|
||
|
|
hana::to<C>(static_cast<Y&&>(y)));
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
//////////////////////////////////////////////////////////////////////////
|
||
|
|
// Model for non-boolean arithmetic data types
|
||
|
|
//////////////////////////////////////////////////////////////////////////
|
||
|
|
template <typename T>
|
||
|
|
struct mult_impl<T, T, when<std::is_arithmetic<T>::value &&
|
||
|
|
!std::is_same<bool, T>::value>> {
|
||
|
|
template <typename X, typename Y>
|
||
|
|
static constexpr decltype(auto) apply(X&& x, Y&& y)
|
||
|
|
{ return static_cast<X&&>(x) * static_cast<Y&&>(y); }
|
||
|
|
};
|
||
|
|
|
||
|
|
//////////////////////////////////////////////////////////////////////////
|
||
|
|
// Model for Constants over a Ring
|
||
|
|
//////////////////////////////////////////////////////////////////////////
|
||
|
|
namespace detail {
|
||
|
|
template <typename C, typename X, typename Y>
|
||
|
|
struct constant_from_mult {
|
||
|
|
static constexpr auto value = hana::mult(hana::value<X>(), hana::value<Y>());
|
||
|
|
using hana_tag = detail::CanonicalConstant<typename C::value_type>;
|
||
|
|
};
|
||
|
|
}
|
||
|
|
|
||
|
|
template <typename C>
|
||
|
|
struct mult_impl<C, C, when<
|
||
|
|
hana::Constant<C>::value &&
|
||
|
|
Ring<typename C::value_type>::value
|
||
|
|
>> {
|
||
|
|
template <typename X, typename Y>
|
||
|
|
static constexpr decltype(auto) apply(X const&, Y const&)
|
||
|
|
{ return hana::to<C>(detail::constant_from_mult<C, X, Y>{}); }
|
||
|
|
};
|
||
|
|
BOOST_HANA_NAMESPACE_END
|
||
|
|
|
||
|
|
#endif // !BOOST_HANA_MULT_HPP
|