distinct_until_changed.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> // member_overload
 
#include <concepts>
#include <functional>
 
namespace rpp::details
{
struct distinct_until_changed_tag;
}
 
namespace rpp::details
{
template<constraint::decayed_type Type, std::equivalence_relation<Type, Type> EqualityFn>
struct distinct_until_changed_impl;
 
template<constraint::decayed_type Type, typename SpecificObservable>
struct member_overload<Type, SpecificObservable, distinct_until_changed_tag>
{
    template<std::equivalence_relation<Type, Type> EqualityFn = std::equal_to<Type>>
    auto distinct_until_changed(EqualityFn&& equality_fn = EqualityFn{}) const & requires is_header_included<distinct_until_changed_tag, EqualityFn>
    {
        return static_cast<const SpecificObservable*>(this)->template lift<Type>(distinct_until_changed_impl<Type, std::decay_t<EqualityFn>>{std::forward<EqualityFn>(equality_fn)});
    }
 
    template<std::equivalence_relation<Type, Type> EqualityFn = std::equal_to<Type>>
    auto distinct_until_changed(EqualityFn&& equality_fn = EqualityFn{}) && requires is_header_included<distinct_until_changed_tag, EqualityFn>
    {
        return std::move(*static_cast<SpecificObservable*>(this)).template lift<Type>(distinct_until_changed_impl <Type, std::decay_t<EqualityFn>>{std::forward<EqualityFn>(equality_fn)});
    }
};
} // namespace rpp::details