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Diffstat (limited to 'boost/hana/fwd/power.hpp')
-rw-r--r-- | boost/hana/fwd/power.hpp | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/boost/hana/fwd/power.hpp b/boost/hana/fwd/power.hpp new file mode 100644 index 0000000000..77ae209a90 --- /dev/null +++ b/boost/hana/fwd/power.hpp @@ -0,0 +1,56 @@ +/*! +@file +Forward declares `boost::hana::power`. + +@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_FWD_POWER_HPP +#define BOOST_HANA_FWD_POWER_HPP + +#include <boost/hana/config.hpp> +#include <boost/hana/core/when.hpp> + + +BOOST_HANA_NAMESPACE_BEGIN + //! Elevate a ring element to its `n`th power. + //! @ingroup group-Ring + //! + //! Specifically, `power(x, n)`, is equivalent to multiplying `x` with + //! itself `n` times using the Ring's multiplication. If the power is + //! equal to `zero`, the Ring's identity (`one`) is returned. + //! + //! @param x + //! A `Ring` element that is elevated to its `n`th power. + //! + //! @param n + //! A non-negative `IntegralConstant` representing the power to which `x` + //! is elevated. + //! + //! + //! @note + //! Only the tag of `x` is used for tag-dispatching. + //! + //! Example + //! ------- + //! @include example/power.cpp +#ifdef BOOST_HANA_DOXYGEN_INVOKED + constexpr auto power = [](auto&& x, auto const& n) -> decltype(auto) { + return tag-dispatched; + }; +#else + template <typename R, typename = void> + struct power_impl : power_impl<R, when<true>> { }; + + struct power_t { + template <typename X, typename N> + constexpr decltype(auto) operator()(X&& x, N const& n) const; + }; + + constexpr power_t power{}; +#endif +BOOST_HANA_NAMESPACE_END + +#endif // !BOOST_HANA_FWD_POWER_HPP |