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/*!
@file
Forward declares `boost::hana::zip_with`.
@copyright Louis Dionne 2013-2017
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_ZIP_WITH_HPP
#define BOOST_HANA_FWD_ZIP_WITH_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Zip one sequence or more with a given function.
//! @ingroup group-Sequence
//!
//! Given a `n`-ary function `f` and `n` sequences `s1, ..., sn`,
//! `zip_with` produces a sequence whose `i`-th element is
//! `f(s1[i], ..., sn[i])`, where `sk[i]` denotes the `i`-th element of
//! the `k`-th sequence. In other words, `zip_with` produces a sequence
//! of the form
//! @code
//! [
//! f(s1[0], ..., sn[0]),
//! f(s1[1], ..., sn[1]),
//! ...
//! f(s1[M], ..., sn[M])
//! ]
//! @endcode
//! where `M` is the length of the sequences, which are all assumed to
//! have the same length. Assuming the sequences to all have the same size
//! allows the library to perform some optimizations. To zip sequences
//! that may have different lengths, `zip_shortest_with` should be used
//! instead. Also note that it is an error to provide no sequence at all,
//! i.e. `zip_with` expects at least one sequence.
//!
//!
//! Example
//! -------
//! @include example/zip_with.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto zip_with = [](auto&& f, auto&& x1, ..., auto&& xn) {
return tag-dispatched;
};
#else
template <typename S, typename = void>
struct zip_with_impl : zip_with_impl<S, when<true>> { };
struct zip_with_t {
template <typename F, typename Xs, typename ...Ys>
constexpr auto operator()(F&& f, Xs&& xs, Ys&& ...ys) const;
};
constexpr zip_with_t zip_with{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_ZIP_WITH_HPP
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