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/// \file
// Range v3 library
//
// Copyright Eric Niebler 2013-present
//
// Use, modification and distribution is subject to the
// Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// Project home: https://github.com/ericniebler/range-v3
//
#ifndef RANGES_V3_FUNCTIONAL_BIND_HPP
#define RANGES_V3_FUNCTIONAL_BIND_HPP
#include <functional>
#include <type_traits>
#include <meta/meta.hpp>
#include <concepts/concepts.hpp>
#include <range/v3/range_fwd.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-functional
/// @{
template<typename T,
typename U = meta::if_<
std::is_lvalue_reference<T>,
std::reference_wrapper<meta::_t<std::remove_reference<T>>>, T &&>>
U bind_forward(meta::_t<std::remove_reference<T>> & t) noexcept
{
return static_cast<U>(t);
}
template<typename T>
T && bind_forward(meta::_t<std::remove_reference<T>> && t) noexcept
{
// This is to catch way sketchy stuff like: forward<int const &>(42)
static_assert(!std::is_lvalue_reference<T>::value, "You didn't just do that!");
return static_cast<T &&>(t);
}
template<typename T>
struct bind_element
: meta::if_c<RANGES_IS_SAME(detail::decay_t<T>, T), meta::id<T>,
bind_element<detail::decay_t<T>>>
{};
template<typename T>
struct bind_element<std::reference_wrapper<T>>
{
using type = T &;
};
template<typename T>
struct bind_element<reference_wrapper<T>>
{
using type = typename reference_wrapper<T>::reference;
};
template<typename T>
using bind_element_t = meta::_t<bind_element<T>>;
template<typename Bind>
struct protector
{
private:
Bind bind_;
public:
protector() = default;
protector(Bind b)
: bind_(std::move(b))
{}
// clang-format off
template<typename...Ts>
auto CPP_auto_fun(operator())(Ts &&...ts)
(
return bind_(static_cast<Ts &&>(ts)...)
)
/// \overload
template<typename...Ts>
auto CPP_auto_fun(operator())(Ts &&...ts) (const)
(
return bind_(static_cast<Ts &&>(ts)...)
)
// clang-format on
};
struct protect_fn
{
template(typename F)(
requires std::is_bind_expression<uncvref_t<F>>::value) //
protector<uncvref_t<F>> operator()(F && f) const
{
return {static_cast<F &&>(f)};
}
/// \overload
template(typename F)(
requires (!std::is_bind_expression<uncvref_t<F>>::value)) //
F operator()(F && f) const
{
return static_cast<F &&>(f);
}
};
/// Protect a callable so that it can be safely used in a bind expression without
/// accidentally becoming a "nested" bind.
/// \ingroup group-functional
/// \sa `protect_fn`
RANGES_INLINE_VARIABLE(protect_fn, protect)
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#endif
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