userdata<T> now works and compiles on MSVC.

It's going to take serious work to make it happen in GCC, plus the fact that 4.9 is still giving me
so many errors I can't even read it...
 I'll let Rapptz figure it out, but later.
Sexy class bindings, yes!

main.cpp

@@ -1,118 +0,0 @@
-#include <sol.hpp>
-#include <sol/demangle.hpp>
-
-namespace sol {
-	
-	template <typename... Tn>
-	struct constructors;
-
-	template <typename T>
-	class lua_class {
-	public:
-		static const std::string classname;
-		static const std::string meta;
-
-	private:
-		std::string luaname;
-		std::vector<std::string> functionnames;
-		std::vector<class_lua_func> functions;
-		std::vector<luaL_Reg> functiontable;
-		std::vector<luaL_Reg> metatable;
-
-		struct maker {
-
-			static int construct( lua_State* L ) {
-				// First argument is now a table that represent the class to instantiate
-				luaL_checktype( L, 1, LUA_TTABLE );
-
-				lua_newtable( L ); // Create table to represent instance
-
-				// Set first argument of new to metatable of instance
-				lua_pushvalue( L, 1 );
-				lua_setmetatable( L, -2 );
-
-				// Do function lookups in metatable
-				lua_pushvalue( L, 1 );
-				lua_setfield( L, 1, "__index" );
-
-				void* userdata = lua_newuserdata( L, sizeof( T ) );
-				T* obj = static_cast<T*>( userdata );
-				std::allocator<T> alloc{ };
-				alloc.construct( obj );
-			}
-
-			template <std::size_t n>
-			static int destruct( lua_State* L ) {
-				void* userdata = lua_touserdata( L, 0 );
-				T* obj = static_cast<T*>( userdata );
-				std::allocator<T> alloc{ };
-				alloc.destroy( obj );
-			}
-		};
-
-		void build_function_tables( ) {
-
-		}
-
-		template <typename... Args, typename Ret, typename... MArgs>
-		void build_function_tables( Ret( T::* func )( MArgs... ), std::string name, Args&&... args ) {
-			functionnames.push_back( std::move( name ) );
-			functions.emplace_back( std::move( func ) );
-			functiontable.push_back( { functionnames.back().c_str(), &lua_func::call } );
-			build_function_tables( std::forward<Args>( args )... );
-		}
-
-	public:
-		template <typename... Args>
-		lua_class( Args&&... args ) : lua_class( classname, std::forward<Args>( args )... ) {
-
-		}
-
-		template <typename... Args>
-		lua_class( std::string name, Args&&... args ) : lua_class( name, constructors<>(), std::forward<Args>( args )... ) {
-
-		}
-
-		template <typename... Args, typename... CArgs>
-		lua_class( std::string name, constructors<CArgs...> c, Args&&... args ) : luaname( std::move( name ) ) {
-			functionnames.reserve( sizeof...( args ) );
-			functiontable.reserve( sizeof...( args ) );
-			metatable.reserve( sizeof...( args ) );
-			build_function_tables( std::forward<Args>( args )... );
-			functiontable.
-		}
-	};
-
-	template <typename T>
-	const std::string lua_class<T>::classname = detail::demangle( typeid( T ) );
-
-	template <typename T>
-	const std::string lua_class<T>::meta = std::string( "sol.stateful." ).append( classname );
-
-}
-
-struct f {
-	int x;
-	f(  ) : x( 1 ) {
-	}
-	f( int x ) : x( x ) { 
-	}
-	int add( int y ) {
-		return x + y;
-	}
-};
-
-#include <iostream>
-
-int main( ) {
-	sol::state s;
-	f x( 20 );
-	
-	sol::lua_class<f> lc{ };
-	std::cout << lc.classname << std::endl;
-	std::cout << lc.meta << std::endl;
-
-	s.set_function( "add", &f::add, f(10) );
-	s.script( "t = add(20)" );
-	std::cout << s.get<int>( "t" );
-}

sol/demangle.hpp

@@ -32,27 +32,27 @@ namespace sol {
 namespace detail {
 
 
-	std::string demangle(const std::type_info& id) {
+    std::string demangle(const std::type_info& id) {
-		/*std::string realname(2048, '\0');
+        /*std::string realname(2048, '\0');
-		DWORD result = UnDecorateSymbolName(id.raw_name(), &realname[0],
+        DWORD result = UnDecorateSymbolName(id.raw_name(), &realname[0],
-			static_cast<DWORD>(realname.size()), UNDNAME_NAME_ONLY | UNDNAME_32_BIT_DECODE);
+            static_cast<DWORD>(realname.size()), UNDNAME_NAME_ONLY | UNDNAME_32_BIT_DECODE);
-		if (result == 0)
+        if (result == 0)
-			return "";
+            return "";
-		realname.resize(result);
+        realname.resize(result);
-		*/
+        */
-		const static std::string removals[ 2 ] = {
+        const static std::string removals[ 2 ] = {
-			"struct ",
+            "struct ",
-			"class "
+            "class "
-		};
+        };
-		std::string realname = id.name( );
+        std::string realname = id.name();
-		for ( std::size_t r = 0; r < 2; ++r ) {
+        for (std::size_t r = 0; r < 2; ++r) {
-			auto found = realname.find( removals[ r ] );
+            auto found = realname.find(removals[ r ]);
-			if ( found == std::string::npos )
+            if (found == std::string::npos)
-				continue;
+                continue;
-			realname.erase( found, removals[r].size() );
+            realname.erase(found, removals[r].size());
-		}
+        }
-		return realname;
+        return realname;
-	}
+    }
 
 #elif __GNUC__ || __clang__
 #include <cxxabi.h>
@@ -60,13 +60,13 @@ namespace detail {
 namespace sol {
 namespace detail {
 
-	std::string demangle(const std::type_info& id) {
+    std::string demangle(const std::type_info& id) {
-		int status;
+        int status;
-		char* unmangled = abi::__cxa_demangle(id.name(), 0, 0, &status);
+        char* unmangled = abi::__cxa_demangle(id.name(), 0, 0, &status);
-		std::string realname = unmangled;
+        std::string realname = unmangled;
-		free(unmangled);
+        free(unmangled);
-		return realname;
+        return realname;
-	}
+    }
 
 #else
 namespace sol {

sol/lua_function.hpp

@@ -26,37 +26,6 @@
 #include <memory>
 
 namespace sol {
-namespace detail {
-template<typename T, std::size_t N>
-void get_upvalue_ptr(lua_State* L, T*& data, std::size_t datasize, std::array<void*, N> voiddata, int& upvalue) {
-    for (std::size_t i = 0, d = 0; d < datasize; ++i, d += sizeof(void*)) {
-        voiddata[i] = lua_touserdata(L, lua_upvalueindex(upvalue++));
-    }
-    data = reinterpret_cast<T*>(static_cast<void*>(voiddata.data()));
-}
-template<typename T, std::size_t N>
-void get_upvalue_ptr(lua_State* L, T*& data, std::array<void*, N> voiddata, int& upvalue) {
-    get_upvalue_ptr(L, data, sizeof(T), voiddata, upvalue);
-}
-template<typename T>
-void get_upvalue_ptr(lua_State* L, T*& data, int& upvalue) {
-    const static std::size_t data_t_count = (sizeof(T)+(sizeof(void*)-1)) / sizeof(void*);
-    typedef std::array<void*, data_t_count> data_t;
-    data_t voiddata{{}};
-    return get_upvalue_ptr(L, data, voiddata, upvalue);
-}
-template<typename T>
-void get_upvalue(lua_State* L, T& data, int& upvalue) {
-    const static std::size_t data_t_count = (sizeof(T)+(sizeof(void*)-1)) / sizeof(void*);
-    typedef std::array<void*, data_t_count> data_t;
-    data_t voiddata{{}};
-    for (std::size_t i = 0, d = 0; d < sizeof(T); ++i, d += sizeof(void*)) {
-        voiddata[i] = lua_touserdata(L, lua_upvalueindex(upvalue++));
-    }
-    data = *reinterpret_cast<T*>(static_cast<void*>(voiddata.data()));
-}
-} // detail
-
 
 template<typename TFx>
 struct static_lua_func {
@@ -83,10 +52,9 @@ struct static_lua_func {
     }
 
     static int call(lua_State* L) {
-        int upvalue = 1;
+       auto udata = stack::get_user<fx_t*>(L);
-        fx_t* fx;
+       fx_t* fx = udata.first;
-        detail::get_upvalue(L, fx, upvalue);
+       int r = typed_call(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), fx, L);
-        int r = typed_call(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), fx, L);
         return r;
     }
 
@@ -122,19 +90,11 @@ struct static_object_lua_func {
     }
 
     static int call(lua_State* L) {
-        const static std::size_t data_t_count = (sizeof(fx_t)+(sizeof(void*)-1)) / sizeof(void*);
+        auto memberdata = stack::get_user<fx_t>(L, 1);
-        typedef std::array<void*, data_t_count> data_t;
+       auto objdata = stack::get_user<T*>(L, memberdata.second);
-        int upvalue = 1;
+       fx_t& memfx = memberdata.first;
-        data_t data = {{}};
+       T& obj = *objdata.first;
-        fx_t* fxptr;
+        int r = typed_call(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), obj, memfx, L);
-        for (std::size_t i = 0, d = 0; d < sizeof(fx_t*); ++i, d += sizeof(void*)) {
-            data[i] = lua_touserdata(L, lua_upvalueindex(upvalue++));
-        }
-        fxptr = reinterpret_cast<fx_t*>(static_cast<void*>(data.data())); 
-        fx_t& mem_ptr = *fxptr;
-        void* objectdata = lua_touserdata(L, lua_upvalueindex(upvalue++));
-        T& obj = *static_cast<T*>(objectdata);
-        int r = typed_call(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), obj, mem_ptr, L);
         return r;
     }
 
@@ -145,7 +105,7 @@ struct static_object_lua_func {
 
 struct lua_func {
     static int call(lua_State* L) {
-        void** pinheritancedata = static_cast<void**>(lua_touserdata(L, lua_upvalueindex(1)));
+        void** pinheritancedata = static_cast<void**>(stack::get<lightuserdata_t>(L, 1).value);
         void* inheritancedata = *pinheritancedata;
         if (inheritancedata == nullptr)
             throw sol_error("call from Lua to C++ function has null data");
@@ -156,7 +116,7 @@ struct lua_func {
     }
 
     static int gc(lua_State* L) {
-        void** puserdata = static_cast<void**>(lua_touserdata(L, 1));
+        void** puserdata = static_cast<void**>(stack::get<userdata_t>(L, 1).value);
         void* userdata = *puserdata;
         lua_func* ptr = static_cast<lua_func*>(userdata);
         std::default_delete<lua_func> dx{};
@@ -175,15 +135,11 @@ template<typename TFx>
 struct functor_lua_func : public lua_func {
     typedef decltype(&TFx::operator()) fx_t;
     typedef function_traits<fx_t> fx_traits;
-    fx_t fx;
+    TFx fx;
 
     template<typename... FxArgs>
     functor_lua_func(FxArgs&&... fxargs): fx(std::forward<FxArgs>(fxargs)...) {}
 
-    virtual int operator()(lua_State* L) override {
-        return (*this)(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), L);
-    }
-
     template<typename... Args>
     int operator()(types<void>, types<Args...> t, lua_State* L) {
         stack::pop_call(L, fx, t);
@@ -202,6 +158,10 @@ struct functor_lua_func : public lua_func {
         stack::push(L, r);
         return sizeof...(Ret);
     }
+
+    virtual int operator()(lua_State* L) override {
+        return (*this)(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), L);
+    }
 };
 
 template<typename TFx, typename T = TFx, bool is_member_pointer = std::is_member_function_pointer<TFx>::value>
@@ -286,21 +246,21 @@ struct class_lua_func : public lua_func {
     typedef typename std::remove_pointer<typename std::decay<TFx>::type>::type fx_t;
     typedef function_traits<fx_t> fx_traits;
     struct functor {
-        T& member;
+        T* item;
         fx_t invocation;
 
         template<typename... FxArgs>
-        functor(FxArgs&&... fxargs): member(*static_cast<T*>(nullptr)), invocation(std::forward<FxArgs>(fxargs)...) {}
+        functor(FxArgs&&... fxargs): item(nullptr), invocation(std::forward<FxArgs>(fxargs)...) {}
 
-	   void pre_call( lua_State* L ) {
+       void pre_call(lua_State* L) {
-		   void* userdata = lua_touserdata( L, 0 );
+            void* userdata = lua_touserdata(L, 0);
-		   T* item = static_cast<T*>( userdata );
+            item = static_cast<T*>(userdata);
-		   member = *item;
+       }
-	   }
 
         template<typename... Args>
         typename fx_traits::return_type operator()(Args&&... args) {
-           return (member.*invocation)(std::forward<Args>(args)...);
+            T& member = *item;
+            return (member.*invocation)(std::forward<Args>(args)...);
         }
     } fx;
 
@@ -309,8 +269,7 @@ struct class_lua_func : public lua_func {
 
     template<typename... Args>
     int operator()(types<void>, types<Args...> t, lua_State* L) {
-        fx.pre_call(L);
+        stack::pop_call(L, fx, t);
-	   stack::pop_call(L, fx, t);
         return 0;
     }
 
@@ -322,13 +281,13 @@ struct class_lua_func : public lua_func {
     template<typename... Ret, typename... Args>
     int operator()(types<Ret...>, types<Args...> t, lua_State* L) {
         typedef typename multi_return<Ret...>::type return_type;
-        fx.pre_call(L);
+        return_type r = stack::pop_call(L, fx, t);
-	   return_type r = stack::pop_call(L, fx, t);
         stack::push(L, std::move(r));
         return sizeof...(Ret);
     }
 
     virtual int operator()(lua_State* L) override {
+        fx.pre_call(L);
         return (*this)(tuple_types<typename fx_traits::return_type>(), typename fx_traits::args_type(), L);
     }
 };

sol/reference.hpp

@@ -46,11 +46,14 @@ public:
         luaL_unref(L, LUA_REGISTRYINDEX, ref);
     }
 
-
     void push() const noexcept {
         lua_rawgeti(L, LUA_REGISTRYINDEX, ref);
     }
 
+    void pop() const noexcept {
+        lua_pop(L, 1);
+    }
+
     reference(reference&& o) noexcept {
         L = o.L;
         ref = o.ref;

sol/stack.hpp

@@ -112,6 +112,16 @@ inline bool get<bool>(lua_State* L, int index) {
     return lua_toboolean(L, index) != 0;
 }
 
+template<>
+inline lightuserdata_t get<lightuserdata_t>(lua_State* L, int index) {
+    return {lua_touserdata(L, lua_upvalueindex(index))};
+}
+
+template<>
+inline userdata_t get<userdata_t>(lua_State* L, int index) {
+    return {lua_touserdata(L, index)};
+}
+
 template<>
 inline std::string get<std::string>(lua_State* L, int index) {
     std::string::size_type len;
@@ -124,6 +134,17 @@ inline const char* get<const char*>(lua_State* L, int index) {
     return lua_tostring(L, index);
 }
 
+template <typename T>
+inline std::pair<T, int> get_user(lua_State* L, int index = 1) {
+    const static std::size_t data_t_count = (sizeof(T)+(sizeof(void*)-1)) / sizeof(void*);
+    typedef std::array<void*, data_t_count> data_t;
+    data_t voiddata{ {} };
+    for (std::size_t i = 0, d = 0; d < sizeof(T); ++i, d += sizeof(void*)) {
+        voiddata[ i ] = stack::get<lightuserdata_t>(L, index++);
+    }
+    return std::pair<T, int>(*reinterpret_cast<T*>(static_cast<void*>(voiddata.data())), index);
+}
+
 template<typename T>
 inline T pop(lua_State* L) {
     auto r = get<T>(L);

sol/state.hpp

@@ -144,9 +144,15 @@ public:
         return *this;
     }
 
-    template<typename T, typename TFx, typename TM>
+    template<typename T, typename TFx, typename TObj>
-    state& set_function(T&& key, TFx&& fx, TM& mem) {
+    state& set_function(T&& key, TFx&& fx, TObj&& obj) {
-        global.set_function(std::forward<T>(key), std::forward<TFx>(fx), mem);
+        global.set_function(std::forward<T>(key), std::forward<TFx>(fx), std::forward<TObj>(obj));
+        return *this;
+    }
+
+    template<typename T>
+    state& set_class(userdata<T>& user) {
+        global.set_class(user);
         return *this;
     }
 

sol/table.hpp

@@ -25,8 +25,7 @@
 #include "proxy.hpp"
 #include "stack.hpp"
 #include "lua_function.hpp"
-#include <array>
+#include "userdata.hpp"
-#include <cstring>
 
 namespace sol {
 namespace detail {
@@ -114,6 +113,46 @@ public:
             std::forward<T>(key), std::forward<TFx>(fx), std::forward<TObj>(obj));
     }
 
+    template <typename T>
+    table& set_class(userdata<T>& user) {
+        push();
+
+        lua_createtable(state(), 0, 0);
+        int classid = lua_gettop(state());
+
+        // Register metatable for user data in registry
+        // using the metaname key generated from the demangled name
+        luaL_newmetatable(state(), user.meta.c_str());
+        int metaid = lua_gettop(state());
+        // Meta functions: have no light up values
+        luaL_setfuncs(state(), user.metatable.data(), 0);
+
+        // Regular functions: each one references an upvalue at its own index,
+        // resulting in [function count] upvalues
+        //luaL_newlib(L, functiontable.data());
+        // the newlib macro doesn't have a form for when you need upvalues:
+        // we duplicate the work below
+        lua_createtable(state(), 0, user.functiontable.size() - 1);
+        for (std::size_t upvalues = 0; upvalues < user.functions.size(); ++upvalues) {
+            stack::push(state(), static_cast<void*>(user.functions[ upvalues ].get()));
+        }
+        luaL_setfuncs(state(), user.functiontable.data(), static_cast<uint32_t>(user.functions.size()));
+        lua_setfield(state(), metaid, "__index");
+
+        // Meta functions: no upvalues
+        lua_createtable(state(), 0, user.metatable.size() - 1);
+        luaL_setfuncs(state(), user.metatable.data(), 0); // 0, for no upvalues
+        lua_setfield(state(), metaid, "__metatable");
+
+        lua_setmetatable(state(), classid);
+
+        lua_setglobal(state(), user.luaname.c_str());
+
+        pop();
+
+        return *this;
+    }
+
     size_t size() const {
         push();
         return lua_rawlen(state(), -1);
@@ -194,7 +233,7 @@ private:
         stack::push(state(), userobjdata);
         luaL_setfuncs(state(), funcreg, upvalues + 1);
 
-        lua_pop(state(), 1);
+       pop();
         return *this;
     }
 
@@ -210,11 +249,10 @@ private:
         };
 
         push();
-
         int upvalues = stack::push_user(state(), target);
         luaL_setfuncs(state(), funcreg, upvalues);
+       pop();
 
-        lua_pop(state(), 1);
         return *this;
     }
 
@@ -243,7 +281,7 @@ private:
         push();
         stack::push_user(state(), userdata, metatablename);
         luaL_setfuncs(state(), funcreg, 1);
-        lua_pop(state(), 1);
+        pop();
         return *this;
     }
 };

sol/traits.hpp

@@ -58,7 +58,7 @@ using Bool = std::integral_constant<bool, B>;
 
 namespace detail {
 template<typename T, bool isclass = std::is_class<Unqualified<T>>::value>
-struct is_function_impl : std::is_function<typename std::remove_pointer<T>::type> { };
+struct is_function_impl : std::is_function<typename std::remove_pointer<T>::type> {};
 
 template<typename T>
 struct is_function_impl<T, true> {
@@ -66,7 +66,7 @@ struct is_function_impl<T, true> {
     using no = struct { char s[2]; };
 
     struct F { void operator()(); };
-    struct Derived : T, F { };
+    struct Derived : T, F {};
     template<typename U, U> struct Check;
 
     template<typename V>
@@ -80,7 +80,7 @@ struct is_function_impl<T, true> {
 } // detail
 
 template<typename T>
-struct Function : Bool<detail::is_function_impl<T>::value> { };
+struct Function : Bool<detail::is_function_impl<T>::value> {};
 
 template<typename TFuncSignature>
 struct function_traits;

sol/tuple.hpp

@@ -73,6 +73,10 @@ struct tuple_types : types<Args...>, std::false_type {};
 
 template<typename... Args>
 struct tuple_types<std::tuple<Args...>> : types<Args...>, std::true_type {};
+
+template <typename... Tn>
+struct constructors {};
+
 } // sol
 
 #endif // SOL_TUPLE_HPP

sol/types.hpp

@@ -31,6 +31,17 @@ struct nil_t {};
 const nil_t nil {};
 struct void_type {};
 const void_type Void {};
+struct lightuserdata_t { 
+    void* value;
+    lightuserdata_t(void* data) : value(data) {} 
+    operator void* () const { return value; }
+};
+
+struct userdata_t { 
+    void* value;
+    userdata_t(void* data) : value(data) {} 
+    operator void* () const { return value; }
+};
 
 enum class type : int {
     none          = LUA_TNONE,
@@ -58,6 +69,8 @@ inline void type_assert(lua_State* L, int index, type expected) {
     }
 }
 
+template <typename T>
+class userdata;
 class table;
 class function;
 class object;
@@ -114,6 +127,16 @@ inline type type_of<bool>() {
     return type::boolean;
 }
 
+template<>
+inline type type_of<lightuserdata_t>() {
+    return type::lightuserdata;
+}
+
+template<>
+inline type type_of<userdata_t>() {
+    return type::userdata;
+}
+
 inline bool operator==(nil_t, nil_t) { return true; }
 inline bool operator!=(nil_t, nil_t) { return false; }
 } // sol

sol/userdata.hpp

@@ -0,0 +1,161 @@
+// The MIT License (MIT)
+
+// Copyright (c) 2013 Danny Y., Rapptz
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software is furnished to do so,
+// subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+#ifndef SOL_USERDATA_HPP
+#define SOL_USERDATA_HPP
+
+#include <sol/state.hpp>
+#include <sol/lua_function.hpp>
+#include <sol/demangle.hpp>
+#include <vector>
+
+namespace sol {
+
+template <typename T>
+class userdata {
+private:
+    friend table;
+    static const std::string classname;
+    static const std::string meta;
+
+    std::string luaname;
+    std::vector<std::string> functionnames;
+    std::vector<std::unique_ptr<lua_func>> functions;
+    std::vector<luaL_Reg> functiontable;
+    std::vector<luaL_Reg> metatable;
+
+    struct constructor {
+        static int construct(lua_State* L) {
+            // First argument is now a table that represent the class to instantiate
+            luaL_checktype(L, 1, LUA_TTABLE);
+
+            lua_createtable(L, 0, 0); // Create table to represent instance
+
+            // Set first argument of new to metatable of instance
+            lua_pushvalue(L, 1);
+            lua_setmetatable(L, -2);
+
+            // Do function lookups in metatable
+            lua_pushvalue(L, 1);
+            lua_setfield(L, 1, "__index");
+
+            void* userdata = lua_newuserdata(L, sizeof(T));
+            T* obj = static_cast<T*>(userdata);
+            std::allocator<T> alloc{};
+            alloc.construct(obj);
+
+            luaL_getmetatable(L, meta.c_str());
+            lua_setmetatable(L, -2);
+            lua_setfield(L, -2, "__self");
+
+            return 1;
+        }
+    };
+
+    template <std::size_t n>
+    struct destructor {
+        static int destruct(lua_State* L) {
+            for (std::size_t i = 0; i < n; ++i) {
+                lightuserdata_t luserdata = stack::get<lightuserdata_t>(L, i);
+            }
+            userdata_t userdata = stack::get<userdata_t>(L, 0);
+            T* obj = static_cast<T*>(userdata.value);
+            std::allocator<T> alloc{};
+            alloc.destroy(obj);
+
+            return 0;
+        }
+    };
+
+    template <std::size_t i>
+    struct class_func {
+        static int call(lua_State* L) {
+            // Zero-based template parameter, but upvalues start at 1
+            void* inheritancedata = stack::get<lightuserdata_t>(L, i + 1);
+            if (inheritancedata == nullptr)
+                throw sol_error("call from Lua to C++ function has null data");
+            lua_func* pfx = static_cast<lua_func*>(inheritancedata);
+            lua_func& fx = *pfx;
+            int r = fx(L);
+            return r;
+        }
+    };
+
+    template <std::size_t n>
+    void build_function_tables() {
+
+    }
+
+    template <std::size_t n, typename... Args, typename Ret, typename... MArgs>
+    void build_function_tables(Ret(T::* func)(MArgs...), std::string name, Args&&... args) {
+        typedef typename std::decay<decltype(func)>::type fx_t;
+        functionnames.push_back(std::move(name));
+        functions.emplace_back(std::make_unique<class_lua_func<fx_t, T>>(std::move(func)));
+        functiontable.push_back({ functionnames.back().c_str(), &class_func<n>::call });
+        build_function_tables<n + 1>(std::forward<Args>(args)...);
+    }
+
+public:
+    template <typename... Args>
+    userdata(Args&&... args) : userdata(classname, std::forward<Args>(args)...) {
+
+    }
+
+    template <typename... Args>
+    userdata(std::string name, Args&&... args) : userdata(name, constructors<>(), std::forward<Args>(args)...) {
+
+    }
+
+    template <typename... Args, typename... CArgs>
+    userdata(constructors<CArgs...> c, Args&&... args) : userdata(classname, std::move(c), std::forward<Args>(args)...) {
+
+    }
+
+    template <typename... Args, typename... CArgs>
+    userdata(std::string name, constructors<CArgs...> c, Args&&... args) : luaname(std::move(name)) {
+        functionnames.reserve(sizeof...(args));
+        functiontable.reserve(sizeof...(args));
+        functions.reserve(sizeof...(args));
+        metatable.reserve(sizeof...(args));
+        build_function_tables<0>(std::forward<Args>(args)...);
+
+        functionnames.push_back("new");
+        functiontable.push_back({ functionnames.back().c_str(), &constructor::construct });
+        functiontable.push_back({ nullptr, nullptr });
+
+        metatable.push_back({ "__gc", &destructor<sizeof...(Args) / 2>::destruct });
+        metatable.push_back({ nullptr, nullptr });
+    }
+
+    void register_into(const table& s) {
+
+    }
+};
+
+template <typename T>
+const std::string userdata<T>::classname = detail::demangle(typeid(T));
+
+template <typename T>
+const std::string userdata<T>::meta = std::string("sol.stateful.").append(classname);
+
+}
+
+#endif SOL_USERDATA_HPP

tests.cpp

@@ -16,6 +16,26 @@ struct object {
 
 };
 
+struct fuser {
+	int x;
+	
+	fuser( ) : x( 0 ) {
+	
+	}
+	
+	fuser( int x ) : x( x ) {
+	
+	}
+
+	int add( int y ) {
+		return x + y;
+	}
+	
+	int add2( int y ) {
+		return x + y + 2;
+	}
+};
+
 int plop_xyz(int x, int y, std::string z) {
     std::cout << x << " " << y << " " << z << std::endl;
     return 11;
@@ -324,3 +344,31 @@ TEST_CASE("tables/operator[]", "Check if operator[] retrieval and setting works
 
     REQUIRE_NOTHROW(assert1(lua.global_table()));
 }
+
+TEST_CASE( "tables/userdata", "Show that we can create classes from userdata and use them" ) {
+
+	sol::state lua;
+
+	sol::userdata<fuser> lc{ &fuser::add, "add", &fuser::add2, "add2" };
+	lua.set_class( lc );
+
+	lua.script( "a = fuser:new()\n"
+		"b = a:add(1)\n"
+		"c = a:add2(1)\n"
+		"\n" );
+
+	sol::object a = lua.get<sol::object>( "a" );
+	sol::object b = lua.get<sol::object>( "b" );
+	sol::object c = lua.get<sol::object>( "c" );
+	REQUIRE( ( a.is<sol::table>( ) ) );
+	auto atype = a.get_type( );
+	auto btype = b.get_type( );
+	auto ctype = c.get_type( );
+	REQUIRE( ( atype == sol::type::table ) );
+	REQUIRE( ( btype == sol::type::number ) );
+	REQUIRE( ( ctype == sol::type::number ) );
+	int bresult = b.as<int>( );
+	int cresult = c.as<int>( );
+	REQUIRE( bresult == 1 );
+	REQUIRE( cresult == 3 );
+}