56 lines
1.6 KiB
C++
56 lines
1.6 KiB
C++
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/*!
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@file
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Forward declares `boost::hana::fuse`.
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@copyright Louis Dionne 2013-2016
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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_FUSE_HPP
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#define BOOST_HANA_FWD_FUSE_HPP
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#include <boost/hana/config.hpp>
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BOOST_HANA_NAMESPACE_BEGIN
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//! Transform a function taking multiple arguments into a function that
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//! can be called with a compile-time `Foldable`.
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//! @ingroup group-Foldable
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//!
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//!
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//! This function is provided for convenience as a different way of
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//! calling `unpack`. Specifically, `fuse(f)` is a function such that
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//! @code
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//! fuse(f)(foldable) == unpack(foldable, f)
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//! == f(x...)
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//! @endcode
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//! where `x...` are the elements in the foldable. This function is
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//! useful when one wants to create a function that accepts a foldable
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//! which is not known yet.
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//!
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//! @note
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//! This function is not tag-dispatched; customize `unpack` instead.
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//!
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//!
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//! Example
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//! -------
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//! @include example/fuse.cpp
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#ifdef BOOST_HANA_DOXYGEN_INVOKED
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constexpr auto fuse = [](auto&& f) {
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return [perfect-capture](auto&& xs) -> decltype(auto) {
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return unpack(forwarded(xs), forwarded(f));
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};
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};
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#else
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struct fuse_t {
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template <typename F>
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constexpr auto operator()(F&& f) const;
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};
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constexpr fuse_t fuse{};
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#endif
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BOOST_HANA_NAMESPACE_END
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#endif // !BOOST_HANA_FWD_FUSE_HPP
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