1 /*! 2 @file 3 Forward declares `boost::hana::mod`. 4 5 @copyright Louis Dionne 2013-2017 6 Distributed under the Boost Software License, Version 1.0. 7 (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) 8 */ 9 10 #ifndef BOOST_HANA_FWD_MOD_HPP 11 #define BOOST_HANA_FWD_MOD_HPP 12 13 #include <boost/hana/config.hpp> 14 #include <boost/hana/core/when.hpp> 15 16 17 BOOST_HANA_NAMESPACE_BEGIN 18 //! Generalized integer modulus. 19 //! @ingroup group-EuclideanRing 20 //! 21 //! Given two elements of an EuclideanRing `x` and `y`, with `y` 22 //! nonzero, `mod` returns the modulus of the division of `x` by `y`. 23 //! In other words, `mod` can be seen as an equivalent to `%`. 24 //! 25 //! Cross-type version of the method 26 //! -------------------------------- 27 //! The `mod` method is "overloaded" to handle distinct data types 28 //! with certain properties. Specifically, `mod` is defined for 29 //! _distinct_ data types `A` and `B` such that 30 //! 1. `A` and `B` share a common data type `C`, as determined by the 31 //! `common` metafunction 32 //! 2. `A`, `B` and `C` are all `EuclideanRing`s when taken individually 33 //! 3. `to<C> : A -> B` and `to<C> : B -> C` are `Ring`-embeddings, as 34 //! determined by the `is_embedding` metafunction. 35 //! 36 //! In that case, `mod` is defined as 37 //! @code 38 //! mod(x, y) = mod(to<C>(x), to<C>(y)) 39 //! @endcode 40 //! 41 //! 42 //! Example 43 //! ------- 44 //! @include example/mod.cpp 45 #ifdef BOOST_HANA_DOXYGEN_INVOKED 46 constexpr auto mod = [](auto&& x, auto&& y) -> decltype(auto) { 47 return tag-dispatched; 48 }; 49 #else 50 template <typename T, typename U, typename = void> 51 struct mod_impl : mod_impl<T, U, when<true>> { }; 52 53 struct mod_t { 54 template <typename X, typename Y> 55 constexpr decltype(auto) operator()(X&& x, Y&& y) const; 56 }; 57 58 constexpr mod_t mod{}; 59 #endif 60 BOOST_HANA_NAMESPACE_END 61 62 #endif // !BOOST_HANA_FWD_MOD_HPP 63