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/*!
@file
Forward declares `boost::hana::for_each`.
@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_FOR_EACH_HPP
#define BOOST_HANA_FWD_FOR_EACH_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Perform an action on each element of a foldable, discarding
//! the result each time.
//! @ingroup group-Foldable
//!
//! Iteration is done from left to right, i.e. in the same order as when
//! using `fold_left`. If the structure is not finite, this method will
//! not terminate.
//!
//!
//! @param xs
//! The structure to iterate over.
//!
//! @param f
//! A function called as `f(x)` for each element `x` of the structure.
//! The result of `f(x)`, whatever it is, is ignored.
//!
//!
//! Example
//! -------
//! @include example/for_each.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto for_each = [](auto&& xs, auto&& f) -> void {
tag-dispatched;
};
#else
template <typename T, typename = void>
struct for_each_impl : for_each_impl<T, when<true>> { };
struct for_each_t {
template <typename Xs, typename F>
constexpr void operator()(Xs&& xs, F&& f) const;
};
constexpr for_each_t for_each{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_FOR_EACH_HPP
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