vn-verdnaturachat/ios/Pods/boost-for-react-native/boost/hana/fwd/fold.hpp

39 lines
1.1 KiB
C++

/*!
@file
Forward declares `boost::hana::fold`.
@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_FOLD_HPP
#define BOOST_HANA_FWD_FOLD_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/fwd/fold_left.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Equivalent to `fold_left`; provided for convenience.
//! @ingroup group-Foldable
//!
//! `fold` is equivalent to `fold_left`. However, it is not tag-dispatched
//! on its own because it is just an alias to `fold_left`. Also note that
//! `fold` can be called with or without an initial state, just like
//! `fold_left`:
//!
//! @code
//! fold(xs, state, f) == fold_left(xs, state, f)
//! fold(xs, f) == fold_left(xs, f)
//! @endcode
//!
//!
//! Example
//! -------
//! @include example/fold.cpp
constexpr auto fold = fold_left;
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_FOLD_HPP