54 lines
1.4 KiB
C++
54 lines
1.4 KiB
C++
/*!
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@file
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Forward declares `boost::hana::less`.
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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_LESS_HPP
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#define BOOST_HANA_FWD_LESS_HPP
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#include <boost/hana/config.hpp>
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#include <boost/hana/core/when.hpp>
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#include <boost/hana/detail/nested_than_fwd.hpp>
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BOOST_HANA_NAMESPACE_BEGIN
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//! Returns a `Logical` representing whether `x` is less than `y`.
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//! @ingroup group-Orderable
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//!
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//!
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//! Signature
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//! ---------
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//! Given a Logical `Bool` and two Orderables `A` and `B` with a common
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//! embedding, the signature is
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//! @f$ \mathrm{less} : A \times B \to Bool @f$.
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//!
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//! @param x, y
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//! Two objects to compare.
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//!
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//!
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//! Example
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//! -------
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//! @include example/less.cpp
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#ifdef BOOST_HANA_DOXYGEN_INVOKED
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constexpr auto less = [](auto&& x, auto&& y) {
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return tag-dispatched;
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};
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#else
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template <typename T, typename U, typename = void>
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struct less_impl : less_impl<T, U, when<true>> { };
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struct less_t : detail::nested_than<less_t> {
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template <typename X, typename Y>
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constexpr auto operator()(X&& x, Y&& y) const;
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};
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constexpr less_t less{};
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#endif
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BOOST_HANA_NAMESPACE_END
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#endif // !BOOST_HANA_FWD_LESS_HPP
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