Implement react::map(func, vector)

libs/react/include/psemek/react/map.hpp

@@ -2,6 +2,8 @@
 
 #include <psemek/react/value.hpp>
 
+#include <vector>
+
 namespace psemek::react
 {
 
@@ -11,7 +13,7 @@ namespace psemek::react
 		template <typename F, typename ... Args>
 		auto map_impl(F func, value<Args> ... args)
 		{
-			using R = decltype(func(std::declval<Args const &>()...));
+			using R = std::decay_t<decltype(func(std::declval<Args const &>()...))>;
 
 			auto node = std::make_shared<detail::node<R>>();
 			auto weak_node = std::weak_ptr{node};
@@ -46,6 +48,57 @@ namespace psemek::react
 			return value<R>(detail::internal_tag{}, std::move(node));
 		}
 
+		template <typename F, typename T>
+		auto map_impl(F func, std::vector<value<T>> args)
+		{
+			using R = std::decay_t<decltype(func(std::declval<std::vector<T>>()))>;
+
+			auto node = std::make_shared<detail::node<R>>();
+			auto weak_node = std::weak_ptr{node};
+
+			auto internal_subscriber = [weak_node]{
+				if (auto node = weak_node.lock())
+				{
+					node->cached_value = std::nullopt;
+					node->internal_signal();
+				}
+			};
+
+			auto external_subscriber = [weak_node](auto const &){
+				if (auto node = weak_node.lock())
+				{
+					if (!node->cached_value)
+						node->external_signal(node->value());
+				}
+			};
+
+			std::vector<util::signal<void>::subscription_token> internal_tokens;
+			std::vector<typename util::signal<T>::subscription_token> external_tokens;
+
+			internal_tokens.reserve(args.size());
+			external_tokens.reserve(args.size());
+
+			for (auto const & arg : args)
+			{
+				internal_tokens.push_back(arg.subscribe(detail::internal_tag{}, internal_subscriber));
+				external_tokens.push_back(arg.subscribe(external_subscriber));
+			}
+
+			node->getter = [
+				func = std::move(func),
+				internal_tokens = std::move(internal_tokens),
+				external_tokens = std::move(external_tokens),
+				args = std::move(args)]() -> R {
+				std::vector<T> arg_values;
+				arg_values.reserve(args.size());
+				for (auto const & arg : args)
+					arg_values.push_back(*arg);
+				return func(std::move(arg_values));
+			};
+
+			return value<R>(detail::internal_tag{}, std::move(node));
+		}
+
 	}
 
 	template <typename F, typename ... Args>
@@ -54,4 +107,16 @@ namespace psemek::react
 		return detail::map_impl(std::move(func), make_value(std::forward<Args>(args))...);
 	}
 
+	template <typename F, typename T>
+	auto map(F func, std::vector<value<T>> args)
+	{
+		return detail::map_impl(std::move(func), std::move(args));
+	}
+
+	template <typename T>
+	value<std::vector<T>> unpack(std::vector<value<T>> args)
+	{
+		return map([](std::vector<T> x) -> std::vector<T> { return x; }, std::move(args));
+	}
+
 }