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/*!
@file
Forward declares `boost::hana::transform`.
@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_TRANSFORM_HPP
#define BOOST_HANA_FWD_TRANSFORM_HPP
#include <boost/hana/config.hpp>
#include <boost/hana/core/when.hpp>
BOOST_HANA_NAMESPACE_BEGIN
//! Map a function over a `Functor`.
//! @ingroup group-Functor
//!
//!
//! Signature
//! ---------
//! Given `F` a Functor, the signature is
//! \f$
//! \mathtt{transform} : F(T) \times (T \to U) \to F(U)
//! \f$
//!
//! @param xs
//! The structure to map `f` over.
//!
//! @param f
//! A function called as `f(x)` on element(s) `x` of the structure,
//! and returning a new value to replace `x` in the structure.
//!
//!
//! Example
//! -------
//! @include example/transform.cpp
#ifdef BOOST_HANA_DOXYGEN_INVOKED
constexpr auto transform = [](auto&& xs, auto&& f) {
return tag-dispatched;
};
#else
template <typename Xs, typename = void>
struct transform_impl : transform_impl<Xs, when<true>> { };
struct transform_t {
template <typename Xs, typename F>
constexpr auto operator()(Xs&& xs, F&& f) const;
};
constexpr transform_t transform{};
#endif
BOOST_HANA_NAMESPACE_END
#endif // !BOOST_HANA_FWD_TRANSFORM_HPP
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