From 95ddf46b55d2314133e1ba5421210f925838810a Mon Sep 17 00:00:00 2001
From: OrfeasZ <orfeaz@gmail.com>
Date: Sat, 17 Sep 2016 18:22:19 +0300
Subject: [PATCH] Introduced a new simple_usertype class which derives from
 usertype.

Exposed an "add" function for it in order to allow adding members one at a time before registration.
Introduced state_view.create_simple_usertype<T>() methods for creating simple_usertypes.
---
 sol/state_view.hpp | 17 ++++++++++++++++-
 sol/table_core.hpp | 22 ++++++++++++++++++++--
 sol/usertype.hpp   | 18 +++++++++++++++++-
 3 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/sol/state_view.hpp b/sol/state_view.hpp
index 3212fe6b..9270b67f 100644
--- a/sol/state_view.hpp
+++ b/sol/state_view.hpp
@@ -355,13 +355,28 @@ namespace sol {
 			global.new_simple_usertype<Class, CTor0, CTor...>(name, std::forward<Args>(args)...);
 			return *this;
 		}
-
+		
 		template<typename Class, typename... CArgs, typename... Args>
 		state_view& new_simple_usertype(const std::string& name, constructors<CArgs...> ctor, Args&&... args) {
 			global.new_simple_usertype<Class>(name, ctor, std::forward<Args>(args)...);
 			return *this;
 		}
 
+		template<typename Class, typename... Args>
+		simple_usertype<Class> create_simple_usertype(Args&&... args) {
+			return global.create_simple_usertype<Class>(std::forward<Args>(args)...);
+		}
+
+		template<typename Class, typename CTor0, typename... CTor, typename... Args>
+		simple_usertype<Class> create_simple_usertype(Args&&... args) {
+			return global.create_simple_usertype<Class, CTor0, CTor...>(std::forward<Args>(args)...);
+		}
+
+		template<typename Class, typename... CArgs, typename... Args>
+		simple_usertype<Class> create_simple_usertype(constructors<CArgs...> ctor, Args&&... args) {
+			return global.create_simple_usertype<Class>(ctor, std::forward<Args>(args)...);
+		}
+
 		template<bool read_only = true, typename... Args>
 		state_view& new_enum(const std::string& name, Args&&... args) {
 			global.new_enum<read_only>(name, std::forward<Args>(args)...);
diff --git a/sol/table_core.hpp b/sol/table_core.hpp
index 663f6181..a8800dae 100644
--- a/sol/table_core.hpp
+++ b/sol/table_core.hpp
@@ -274,7 +274,7 @@ namespace sol {
 
 		template<typename Class, typename... Args>
 		basic_table_core& new_simple_usertype(const std::string& name, Args&&... args) {
-			usertype<Class> utype(simple, base_t::lua_state(), std::forward<Args>(args)...);
+			simple_usertype<Class> utype(base_t::lua_state(), std::forward<Args>(args)...);
 			set_usertype(name, utype);
 			return *this;
 		}
@@ -287,11 +287,29 @@ namespace sol {
 
 		template<typename Class, typename... CArgs, typename... Args>
 		basic_table_core& new_simple_usertype(const std::string& name, constructors<CArgs...> ctor, Args&&... args) {
-			usertype<Class> utype(simple, base_t::lua_state(), ctor, std::forward<Args>(args)...);
+			simple_usertype<Class> utype(base_t::lua_state(), ctor, std::forward<Args>(args)...);
 			set_usertype(name, utype);
 			return *this;
 		}
 
+		template<typename Class, typename... Args>
+		simple_usertype<Class> create_simple_usertype(Args&&... args) {
+			simple_usertype<Class> utype(base_t::lua_state(), std::forward<Args>(args)...);
+			return utype;
+		}
+
+		template<typename Class, typename CTor0, typename... CTor, typename... Args>
+		simple_usertype<Class> create_simple_usertype(Args&&... args) {
+			constructors<types<CTor0, CTor...>> ctor{};
+			return create_simple_usertype<Class>(ctor, std::forward<Args>(args)...);
+		}
+
+		template<typename Class, typename... CArgs, typename... Args>
+		simple_usertype<Class> create_simple_usertype(constructors<CArgs...> ctor, Args&&... args) {
+			simple_usertype<Class> utype(base_t::lua_state(), ctor, std::forward<Args>(args)...);
+			return utype;
+		}
+
 		template<bool read_only = true, typename... Args>
 		basic_table_core& new_enum(const std::string& name, Args&&... args) {
 			if (read_only) {
diff --git a/sol/usertype.hpp b/sol/usertype.hpp
index dfe9cd0a..c841184b 100644
--- a/sol/usertype.hpp
+++ b/sol/usertype.hpp
@@ -32,7 +32,7 @@ namespace sol {
 
 	template<typename T>
 	class usertype {
-	private:
+	protected:
 		std::unique_ptr<usertype_detail::registrar, detail::deleter> metatableregister;
 
 		template<typename... Args>
@@ -63,6 +63,22 @@ namespace sol {
 		}
 	};
 
+	template<typename T>
+	class simple_usertype : public usertype<T> {
+	protected:
+		lua_State* state;
+
+	public:
+		template<typename... Args>
+		simple_usertype(lua_State* L, Args&&... args) : state(L), usertype(simple, L, std::forward<Args>(args)...) {}
+		
+		template <typename N, typename F>
+		void add(N&& n, F&& f) {
+			auto meta = (simple_usertype_metatable<T>*) metatableregister.get();
+			meta->add(state, n, f);
+		}
+	};
+
 	namespace stack {
 		template<typename T>
 		struct pusher<usertype<T>> {