63 lines
2.2 KiB
C++
63 lines
2.2 KiB
C++
/*!
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@file
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Forward declares `boost::hana::zip_shortest_with`.
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@copyright Louis Dionne 2013-2017
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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*/
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#ifndef BOOST_HANA_FWD_ZIP_SHORTEST_WITH_HPP
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#define BOOST_HANA_FWD_ZIP_SHORTEST_WITH_HPP
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#include <boost/hana/config.hpp>
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#include <boost/hana/core/when.hpp>
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namespace boost { namespace hana {
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//! Zip one sequence or more with a given function.
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//! @ingroup group-Sequence
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//!
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//! Given a `n`-ary function `f` and `n` sequences `s1, ..., sn`,
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//! `zip_shortest_with` produces a sequence whose `i`-th element is
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//! `f(s1[i], ..., sn[i])`, where `sk[i]` denotes the `i`-th element of
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//! the `k`-th sequence. In other words, `zip_shortest_with` produces a
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//! sequence of the form
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//! @code
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//! [
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//! f(s1[0], ..., sn[0]),
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//! f(s1[1], ..., sn[1]),
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//! ...
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//! f(s1[M], ..., sn[M])
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//! ]
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//! @endcode
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//! where `M` is the length of the shortest sequence. Hence, the returned
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//! sequence stops when the shortest input sequence is exhausted. If you
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//! know that all the sequences you are about to zip have the same length,
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//! you should use `zip_with` instead, since it can be more optimized.
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//! Also note that it is an error to provide no sequence at all, i.e.
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//! `zip_shortest_with` expects at least one sequence.
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//!
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//!
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//! Example
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//! -------
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//! @include example/zip_shortest_with.cpp
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#ifdef BOOST_HANA_DOXYGEN_INVOKED
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constexpr auto zip_shortest_with = [](auto&& f, auto&& x1, ..., auto&& xn) {
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return tag-dispatched;
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};
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#else
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template <typename S, typename = void>
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struct zip_shortest_with_impl : zip_shortest_with_impl<S, when<true>> { };
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struct zip_shortest_with_t {
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template <typename F, typename Xs, typename ...Ys>
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constexpr auto operator()(F&& f, Xs&& xs, Ys&& ...ys) const;
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};
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BOOST_HANA_INLINE_VARIABLE constexpr zip_shortest_with_t zip_shortest_with{};
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#endif
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}} // end namespace boost::hana
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#endif // !BOOST_HANA_FWD_ZIP_SHORTEST_WITH_HPP
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