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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_COMPOSE_HPP
#define RANGES_V3_FUNCTIONAL_COMPOSE_HPP
#include <type_traits>
#include <utility>
#include <concepts/concepts.hpp>
#include <range/v3/detail/config.hpp>
#include <range/v3/functional/invoke.hpp>
#include <range/v3/utility/static_const.hpp>
#include <range/v3/detail/prologue.hpp>
namespace ranges
{
/// \addtogroup group-functional
/// @{
template<typename Second, typename First>
struct composed
{
private:
RANGES_NO_UNIQUE_ADDRESS
First first_;
RANGES_NO_UNIQUE_ADDRESS
Second second_;
// clang-format off
template<typename A, typename B, typename... Ts>
static constexpr auto //
CPP_auto_fun(do_)(A &&a, B &&b, std::false_type, Ts &&... ts)
(
return invoke((B &&) b, invoke((A &&) a, (Ts &&) ts...))
)
template<typename A, typename B, typename... Ts>
static constexpr auto CPP_auto_fun(do_)(A &&a, B &&b, std::true_type, Ts &&... ts)
(
return (invoke((A &&) a, (Ts &&) ts...), invoke((B &&) b))
)
public:
composed() = default;
// clang-format on
constexpr composed(Second second, First first)
: first_(std::move(first))
, second_(std::move(second))
{}
// clang-format off
template<typename... Ts>
constexpr auto CPP_auto_fun(operator())(Ts &&... ts)(mutable &)
(
return composed::do_(first_,
second_,
std::is_void<invoke_result_t<First &, Ts...>>{},
(Ts &&) ts...)
)
template<typename... Ts>
constexpr auto CPP_auto_fun(operator())(Ts &&... ts)(const &)
(
return composed::do_((First const &)first_,
(Second const &)second_,
std::is_void<invoke_result_t<First const &, Ts...>>{},
(Ts &&) ts...)
)
template<typename... Ts>
constexpr auto CPP_auto_fun(operator())(Ts &&... ts)(mutable &&)
(
return composed::do_((First &&)first_,
(Second &&)second_,
std::is_void<invoke_result_t<First &&, Ts...>>{},
(Ts &&) ts...)
)
// clang-format on
};
struct compose_fn
{
template<typename Second, typename First>
constexpr composed<Second, First> operator()(Second second, First first) const
{
return {std::move(second), std::move(first)};
}
};
/// \ingroup group-functional
/// \sa `compose_fn`
RANGES_INLINE_VARIABLE(compose_fn, compose)
/// @}
} // namespace ranges
#include <range/v3/detail/epilogue.hpp>
#endif
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