/*!
|
@file
|
Forward declares `boost::hana::lift`.
|
|
@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_LIFT_HPP
|
#define BOOST_HANA_FWD_LIFT_HPP
|
|
#include <boost/hana/config.hpp>
|
#include <boost/hana/core/when.hpp>
|
|
|
BOOST_HANA_NAMESPACE_BEGIN
|
//! Lift a value into an `Applicative` structure.
|
//! @ingroup group-Applicative
|
//!
|
//! `lift<A>` takes a normal value and embeds it into a structure whose
|
//! shape is represented by the `A` `Applicative`. Note that the value
|
//! may be a function, in which case the created structure may be
|
//! `ap`plied to another `Applicative` structure containing values.
|
//!
|
//!
|
//! Signature
|
//! ---------
|
//! Given an Applicative `A`, the signature is
|
//! @f$ \mathtt{lift}_A : T \to A(T) @f$.
|
//!
|
//! @tparam A
|
//! A tag representing the `Applicative` into which the value is lifted.
|
//!
|
//! @param x
|
//! The value to lift into the applicative.
|
//!
|
//!
|
//! Example
|
//! -------
|
//! @include example/lift.cpp
|
#ifdef BOOST_HANA_DOXYGEN_INVOKED
|
template <typename A>
|
constexpr auto lift = [](auto&& x) {
|
return tag-dispatched;
|
};
|
#else
|
template <typename A, typename = void>
|
struct lift_impl : lift_impl<A, when<true>> { };
|
|
template <typename A>
|
struct lift_t {
|
template <typename X>
|
constexpr auto operator()(X&& x) const;
|
};
|
|
template <typename A>
|
constexpr lift_t<A> lift{};
|
#endif
|
BOOST_HANA_NAMESPACE_END
|
|
#endif // !BOOST_HANA_FWD_LIFT_HPP
|
