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- /*!
- @file
- Forward declares `boost::hana::any`.
- @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_ANY_HPP
- #define BOOST_HANA_FWD_ANY_HPP
- #include <boost/hana/config.hpp>
- #include <boost/hana/core/when.hpp>
- BOOST_HANA_NAMESPACE_BEGIN
- //! Returns whether any key of the structure is true-valued.
- //! @ingroup group-Searchable
- //!
- //! The keys of the structure must be `Logical`s. If the structure is not
- //! finite, a true-valued key must appear at a finite "index" in order for
- //! this method to finish.
- //!
- //!
- //! Example
- //! -------
- //! @include example/any.cpp
- #ifdef BOOST_HANA_DOXYGEN_INVOKED
- constexpr auto any = [](auto&& xs) {
- return tag-dispatched;
- };
- #else
- template <typename S, typename = void>
- struct any_impl : any_impl<S, when<true>> { };
- struct any_t {
- template <typename Xs>
- constexpr auto operator()(Xs&& xs) const;
- };
- constexpr any_t any{};
- #endif
- BOOST_HANA_NAMESPACE_END
- #endif // !BOOST_HANA_FWD_ANY_HPP
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