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/*!
@file
Forward declares `boost::hana::replace`.
@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_REPLACE_HPP
#define BOOST_HANA_FWD_REPLACE_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Replace all the elements of a structure that compare equal
//! to some `value` with some new fixed value.
//! @ingroup group-Functor
//!
//!
//! Signature
//! ---------
//! Given `F` a Functor and `U` a type that can be compared with `T`,
//! the signature is
//! \f$
//! \mathtt{replace} : F(T) \times U \times T \to F(T)
//! \f$
//!
//! @param xs
//! The structure to replace elements of.
//!
//! @param oldval
//! An object compared with each element of the structure. Elements
//! of the structure that compare equal to `oldval` are replaced
//! by `newval` in the new structure.
//!
//! @param newval
//! A value by which every element `x` of the structure that compares
//! equal to `oldval` is replaced.
//!
//!
//! Example
//! -------
//! @include example/replace.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto replace = [](auto&& xs, auto&& oldval, auto&& newval) {
return tag-dispatched;
};
#else
template <typename Xs, typename = void>
struct replace_impl : replace_impl<Xs, when<true>> { };
struct replace_t {
template <typename Xs, typename OldVal, typename NewVal>
constexpr auto operator()(Xs&& xs, OldVal&& oldval, NewVal&& newval) const;
};
constexpr replace_t replace{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_REPLACE_HPP
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