Current File : //backups/router/usr/local/include/boost/hana/fwd/cartesian_product.hpp
/*!
@file
Forward declares `boost::hana::cartesian_product`.
Copyright Louis Dionne 2013-2022
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>
namespace boost { namespace hana {
//! 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
#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;
};
BOOST_HANA_INLINE_VARIABLE constexpr cartesian_product_t cartesian_product{};
#endif
}} // end namespace boost::hana
#endif // !BOOST_HANA_FWD_CARTESIAN_PRODUCT_HPP
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