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Diffstat (limited to 'boost/hana/fwd/any.hpp')
| -rw-r--r-- | boost/hana/fwd/any.hpp | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/boost/hana/fwd/any.hpp b/boost/hana/fwd/any.hpp new file mode 100644 index 0000000000..2adf3beeee --- /dev/null +++ b/boost/hana/fwd/any.hpp @@ -0,0 +1,46 @@ +/*! +@file +Forward declares `boost::hana::any`. + +@copyright Louis Dionne 2013-2016 +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 |