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Diffstat (limited to 'boost/hana/fwd/cartesian_product.hpp')
-rw-r--r-- | boost/hana/fwd/cartesian_product.hpp | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/boost/hana/fwd/cartesian_product.hpp b/boost/hana/fwd/cartesian_product.hpp new file mode 100644 index 0000000000..4df7917415 --- /dev/null +++ b/boost/hana/fwd/cartesian_product.hpp @@ -0,0 +1,70 @@ +/*! +@file +Forward declares `boost::hana::cartesian_product`. + +@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_CARTESIAN_PRODUCT_HPP +#define BOOST_HANA_FWD_CARTESIAN_PRODUCT_HPP + +#include <boost/hana/config.hpp> +#include <boost/hana/core/when.hpp> + + +BOOST_HANA_NAMESPACE_BEGIN + //! Computes the cartesian product of a sequence of sequences. + //! @ingroup group-Sequence + //! + //! Given a sequence of sequences, `cartesian_product` returns a new + //! sequence of sequences containing the cartesian product of the + //! original sequences. For this method to finish, a finite number + //! of finite sequences must be provided. + //! + //! @note + //! All the sequences must have the same tag, and that tag must also match + //! that of the top-level sequence. + //! + //! + //! Signature + //! --------- + //! Given a `Sequence` `S(T)`, the signature is + //! \f[ + //! \mathtt{cartesian\_product} : S(S(T)) \to S(S(T)) + //! \f] + //! + //! @param xs + //! A sequence of sequences of which the cartesian product is computed. + //! + //! + //! Example + //! ------- + //! @include example/cartesian_product.cpp + //! + //! + //! Benchmarks + //! ---------- + //! <div class="benchmark-chart" + //! style="min-width: 310px; height: 400px; margin: 0 auto" + //! data-dataset="benchmark.cartesian_product.compile.json"> + //! </div> +#ifdef BOOST_HANA_DOXYGEN_INVOKED + constexpr auto cartesian_product = [](auto&& xs) { + return tag-dispatched; + }; +#else + template <typename S, typename = void> + struct cartesian_product_impl : cartesian_product_impl<S, when<true>> { }; + + struct cartesian_product_t { + template <typename Xs> + constexpr auto operator()(Xs&& xs) const; + }; + + constexpr cartesian_product_t cartesian_product{}; +#endif +BOOST_HANA_NAMESPACE_END + +#endif // !BOOST_HANA_FWD_CARTESIAN_PRODUCT_HPP |