any.hpp
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/*!
@file
Forward declares `boost::hana::any`.
Copyright Louis Dionne 2013-2022
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>
namespace boost { namespace hana {
//! 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;
};
BOOST_HANA_INLINE_VARIABLE constexpr any_t any{};
#endif
}} // end namespace boost::hana
#endif // !BOOST_HANA_FWD_ANY_HPP