From 08b14ded933fdadb9cac381347f09195daafc63e Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Sat, 16 Dec 2023 21:55:59 +0300
Subject: [PATCH] Add static_assert to notify when a function is not invocable
 in ecs::container::apply & batch_apply

---
 libs/ecs/include/psemek/ecs/container.hpp        |  2 ++
 .../include/psemek/ecs/detail/apply_helper.hpp   | 16 ++++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/libs/ecs/include/psemek/ecs/container.hpp b/libs/ecs/include/psemek/ecs/container.hpp
index 9da9497e..c3caa449 100644
--- a/libs/ecs/include/psemek/ecs/container.hpp
+++ b/libs/ecs/include/psemek/ecs/container.hpp
@@ -451,6 +451,7 @@ namespace psemek::ecs
 	query_cache container::apply(Function && function, query_cache cache)
 	{
 		static_assert(detail::all_different_types_v<std::remove_const_t<Components>...>, "all component types must be different");
+		static_assert(detail::invocable<Function, Components...>, "function is not invocable with these components");
 
 		if (!cache)
 			cache = this->cache<Components...>();
@@ -495,6 +496,7 @@ namespace psemek::ecs
 	query_cache container::batch_apply(Function && function, query_cache cache)
 	{
 		static_assert(detail::all_different_types_v<std::remove_const_t<Components>...>, "all component types must be different");
+		static_assert(detail::batch_invocable<Function, Components...>, "function is not batch-invocable with these components");
 
 		if (!cache)
 			cache = this->cache<Components...>();
diff --git a/libs/ecs/include/psemek/ecs/detail/apply_helper.hpp b/libs/ecs/include/psemek/ecs/detail/apply_helper.hpp
index a3af84c9..27d31fa0 100644
--- a/libs/ecs/include/psemek/ecs/detail/apply_helper.hpp
+++ b/libs/ecs/include/psemek/ecs/detail/apply_helper.hpp
@@ -15,6 +15,14 @@ namespace psemek::ecs
 namespace psemek::ecs::detail
 {
 
+	template <typename Function, typename ... Components>
+	constexpr bool invocable = false
+		|| std::invocable<Function, container &, handle, Components & ...>
+		|| std::invocable<Function, container &, Components & ...>
+		|| std::invocable<Function, handle, Components & ...>
+		|| std::invocable<Function, Components & ...>
+		;
+
 	template <typename Function, typename ... Components>
 	void invoke(Function && function, container & parent, handle const & handle, Components & ... components)
 	{
@@ -36,6 +44,14 @@ namespace psemek::ecs::detail
 		}
 	}
 
+	template <typename Function, typename ... Components>
+	constexpr bool batch_invocable = false
+		|| std::invocable<Function, container &, util::span<handle const>, util::span<Components> ...>
+		|| std::invocable<Function, container &, util::span<Components> ...>
+		|| std::invocable<Function, util::span<handle const>, util::span<Components> ...>
+		|| std::invocable<Function, util::span<Components> ...>
+		;
+
 	template <typename Function, typename ... Components>
 	void batch_invoke(Function && function, container & parent, std::size_t count, handle const * handles, Components * ... components)
 	{