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- /*!
- @file
- Forward declares `boost::hana::and_`.
- @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_AND_HPP
- #define BOOST_HANA_FWD_AND_HPP
- #include <boost/hana/config.hpp>
- #include <boost/hana/core/when.hpp>
- BOOST_HANA_NAMESPACE_BEGIN
- //! Return whether all the arguments are true-valued.
- //! @ingroup group-Logical
- //!
- //! `and_` can be called with one argument or more. When called with
- //! two arguments, `and_` uses tag-dispatching to find the right
- //! implementation. Otherwise,
- //! @code
- //! and_(x) == x
- //! and_(x, y, ...z) == and_(and_(x, y), z...)
- //! @endcode
- //!
- //!
- //! Example
- //! -------
- //! @include example/and.cpp
- #ifdef BOOST_HANA_DOXYGEN_INVOKED
- constexpr auto and_ = [](auto&& x, auto&& ...y) -> decltype(auto) {
- return tag-dispatched;
- };
- #else
- template <typename L, typename = void>
- struct and_impl : and_impl<L, when<true>> { };
- struct and_t {
- template <typename X, typename Y>
- constexpr decltype(auto) operator()(X&& x, Y&& y) const;
- template <typename X, typename ...Y>
- constexpr decltype(auto) operator()(X&& x, Y&& ...y) const;
- };
- constexpr and_t and_{};
- #endif
- BOOST_HANA_NAMESPACE_END
- #endif // !BOOST_HANA_FWD_AND_HPP
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