From 546c0f2a7be61d9ef6fc067c92aaa05ce5156fae Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Sun, 28 Jul 2024 19:23:11 +0300
Subject: [PATCH] Support subscribing to react::value forever

---
 libs/react/include/psemek/react/value.hpp | 27 +++++++++++++++++------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/libs/react/include/psemek/react/value.hpp b/libs/react/include/psemek/react/value.hpp
index ebda9491..884cbf6b 100644
--- a/libs/react/include/psemek/react/value.hpp
+++ b/libs/react/include/psemek/react/value.hpp
@@ -17,6 +17,9 @@ namespace psemek::react
 		struct internal_tag
 		{};
 
+		struct forever_tag
+		{};
+
 		template <typename T>
 		struct node
 		{
@@ -65,6 +68,8 @@ namespace psemek::react
 
 	}
 
+	static constexpr detail::forever_tag forever;
+
 	template <typename T>
 	struct value
 	{
@@ -105,16 +110,16 @@ namespace psemek::react
 
 		[[nodiscard]] auto subscribe(typename detail::node<T>::external_subscriber subscriber, bool call = false) const
 		{
-			if (call)
-			{
-				if constexpr (std::is_same_v<T, void>)
-					subscriber();
-				else
-					subscriber(node_->value());
-			}
+			if (call) this->call(subscriber);
 			return node_->external_signal.subscribe(std::move(subscriber));
 		}
 
+		void subscribe(typename detail::node<T>::external_subscriber subscriber, detail::forever_tag, bool call = false) const
+		{
+			if (call) this->call(subscriber);
+			node_->external_signal.subscribe_forever(std::move(subscriber));
+		}
+
 		[[nodiscard]] auto subscribe(detail::internal_tag, std::function<void()> subscriber) const
 		{
 			return node_->internal_signal.subscribe(std::move(subscriber));
@@ -122,6 +127,14 @@ namespace psemek::react
 
 	protected:
 		std::shared_ptr<detail::node<T>> node_;
+
+		void call(typename detail::node<T>::external_subscriber const & subscriber) const
+		{
+			if constexpr (std::is_same_v<T, void>)
+				subscriber();
+			else
+				subscriber(node_->value());
+		}
 	};
 
 	template <typename T>