57 lines
1.6 KiB
C++
57 lines
1.6 KiB
C++
/*!
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@file
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Forward declares `boost::hana::power`.
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@copyright Louis Dionne 2013-2016
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_HANA_FWD_POWER_HPP
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#define BOOST_HANA_FWD_POWER_HPP
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#include <boost/hana/config.hpp>
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#include <boost/hana/core/when.hpp>
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BOOST_HANA_NAMESPACE_BEGIN
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//! Elevate a ring element to its `n`th power.
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//! @ingroup group-Ring
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//!
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//! Specifically, `power(x, n)`, is equivalent to multiplying `x` with
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//! itself `n` times using the Ring's multiplication. If the power is
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//! equal to `zero`, the Ring's identity (`one`) is returned.
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//!
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//! @param x
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//! A `Ring` element that is elevated to its `n`th power.
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//!
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//! @param n
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//! A non-negative `IntegralConstant` representing the power to which `x`
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//! is elevated.
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//!
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//!
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//! @note
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//! Only the tag of `x` is used for tag-dispatching.
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//!
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//! Example
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//! -------
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//! @include example/power.cpp
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#ifdef BOOST_HANA_DOXYGEN_INVOKED
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constexpr auto power = [](auto&& x, auto const& n) -> decltype(auto) {
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return tag-dispatched;
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};
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#else
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template <typename R, typename = void>
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struct power_impl : power_impl<R, when<true>> { };
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struct power_t {
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template <typename X, typename N>
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constexpr decltype(auto) operator()(X&& x, N const& n) const;
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};
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constexpr power_t power{};
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#endif
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BOOST_HANA_NAMESPACE_END
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#endif // !BOOST_HANA_FWD_POWER_HPP
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