scan.hpp

//                  ReactivePlusPlus library
//
//          Copyright Aleksey Loginov 2022 - present.
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE_1_0.txt or copy at
//          https://www.boost.org/LICENSE_1_0.txt)
//
// Project home: https://github.com/victimsnino/ReactivePlusPlus
//
 
#pragma once
 
#include <rpp/observables/details/member_overload.hpp>
 
namespace rpp::details
{
struct scan_tag;
}
 
namespace rpp::details
{
// accepts Result and Type and returns Result
template<typename Fn, typename Result, typename Type>
concept scan_accumulator = reduce_accumulator<Fn,Result,Type>;
 
template<constraint::decayed_type Type, constraint::decayed_type Result, scan_accumulator<Result, Type> AccumulatorFn>
struct scan_impl;
 
template<constraint::decayed_type Type, typename SpecificObservable>
struct member_overload<Type, SpecificObservable, scan_tag>
{
    template<typename Result, scan_accumulator<Result, Type> AccumulatorFn>
    auto scan(Result&& initial_value, AccumulatorFn&& accumulator) const & requires is_header_included<scan_tag, Result, AccumulatorFn>
    {
        return static_cast<const SpecificObservable*>(this)->template lift<std::decay_t<Result>>(scan_impl<Type, std::decay_t<Result>, std::decay_t<AccumulatorFn>>{std::forward<Result>(initial_value), std::forward<AccumulatorFn>(accumulator)});
    }
 
    template<typename Result, scan_accumulator<Result, Type> AccumulatorFn>
    auto scan(Result&& initial_value, AccumulatorFn&& accumulator) && requires is_header_included<scan_tag, Result, AccumulatorFn>
    {
        return std::move(*static_cast<SpecificObservable*>(this)).template lift<std::decay_t<Result>>(scan_impl<Type, std::decay_t<Result>, std::decay_t<AccumulatorFn>>{std::forward<Result>(initial_value), std::forward<AccumulatorFn>(accumulator)});
    }
};
} // namespace rpp::details