Make various arguments push based on the Lua state passed, not on the Lua state they have (avoids a small class of errors and makes the panic function call tiself more regularly).

docs/source/api/state.rst

@@ -102,13 +102,32 @@ Get either the global table or the Lua registry as a :doc:`sol::table<table>`, w
 
 
 .. code-block:: cpp
-	:caption: function: Lua set_panic
+	:caption: function: set_panic
 	:name: set-panic
 
 	void set_panic(lua_CFunction panic);
 
 Overrides the panic function Lua calls when something unrecoverable or unexpected happens in the Lua VM. Must be a function of the that matches the ``int(lua_State*)`` function signature.
 
+
+.. code-block:: cpp
+	:caption: function: memory_used
+	:name: memory-used
+
+	std::size_t memory_used() const;
+
+Returns the amount of memory used *in bytes* by the Lua State.
+
+
+.. code-block:: cpp
+	:caption: function: collect_garbage
+	:name: collect-garbage
+
+	void collect_garbage();
+
+Attempts to run the garbage collector. Note that this is subject to the same rules as the Lua API's collect_garbage function: memory may or may not be freed, depending on dangling references or other things, so make sure you don't have tables or other stack-referencing items currently alive or referenced that you want to be collected.
+
+
 .. code-block:: cpp
 	:caption: function: make a table
 

docs/source/conf.py

@@ -61,7 +61,7 @@ author = 'ThePhD'
 # The short X.Y version.
 version = '2.15'
 # The full version, including alpha/beta/rc tags.
-release = '2.15.3'
+release = '2.15.5'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.

sol/proxy.hpp

@@ -168,9 +168,9 @@ namespace sol {
 	namespace stack {
 		template <typename Table, typename Key>
 		struct pusher<proxy<Table, Key>> {
-			static int push(lua_State*, const proxy<Table, Key>& p) {
+			static int push(lua_State* L, const proxy<Table, Key>& p) {
 				sol::reference r = p;
-				return r.push();
+				return r.push(L);
 			}
 		};
 	} // stack

sol/reference.hpp

@@ -134,12 +134,20 @@ namespace sol {
 		}
 
 		int push() const noexcept {
-			lua_rawgeti(lua_state(), LUA_REGISTRYINDEX, ref);
+			return push(lua_state());
+		}
+
+		int push(lua_State* Ls) const noexcept {
+			lua_rawgeti(Ls, LUA_REGISTRYINDEX, ref);
 			return 1;
 		}
 
-		void pop(int n = 1) const noexcept {
-			lua_pop(lua_state(), n);
+		void pop() const noexcept {
+			pop(lua_state());
+		}
+
+		void pop(lua_State* Ls, int n = 1) const noexcept {
+			lua_pop(Ls, n);
 		}
 
 		int registry_index() const noexcept {

sol/stack_proxy.hpp

@@ -43,7 +43,11 @@ namespace sol {
 		}
 
 		int push() const {
-			lua_pushvalue(L, index);
+			return push(L);
+		}
+
+		int push(lua_State* Ls) const {
+			lua_pushvalue(Ls, index);
 			return 1;
 		}
 

sol/stack_push.hpp

@@ -243,12 +243,12 @@ namespace sol {
 
 		template<typename T>
 		struct pusher<T, std::enable_if_t<std::is_base_of<reference, T>::value || std::is_base_of<stack_reference, T>::value>> {
-			static int push(lua_State*, const T& ref) {
-				return ref.push();
+			static int push(lua_State* L, const T& ref) {
+				return ref.push(L);
 			}
 
-			static int push(lua_State*, T&& ref) {
-				return ref.push();
+			static int push(lua_State* L, T&& ref) {
+				return ref.push(L);
 			}
 		};
 

sol/stack_reference.hpp

@@ -45,12 +45,20 @@ namespace sol {
 		stack_reference& operator=(const stack_reference&) noexcept = default;
 
 		int push() const noexcept {
-			lua_pushvalue(L, index);
+			return push(lua_state());
+		}
+
+		int push(lua_State* Ls) const noexcept {
+			lua_pushvalue(Ls, index);
 			return 1;
 		}
 
-		void pop(int n = 1) const noexcept {
-			lua_pop(lua_state(), n);
+		void pop() const noexcept {
+			pop(lua_state());
+		}
+
+		void pop(lua_State* Ls, int n = 1) const noexcept {
+			lua_pop(Ls, n);
 		}
 
 		int stack_index() const noexcept {

sol/state_view.hpp

@@ -45,6 +45,13 @@ namespace sol {
 		count
 	};
 
+	inline std::size_t total_memory_used(lua_State* L) {
+		std::size_t kb = lua_gc(L, LUA_GCCOUNT, 0);
+		kb *= 1024;
+		kb += lua_gc(L, LUA_GCCOUNTB, 0);
+		return kb;
+	}
+
 	class state_view {
 	private:
 		lua_State* L;
@@ -291,6 +298,14 @@ namespace sol {
 			return reg;
 		}
 
+		std::size_t memory_used() const {
+			return total_memory_used(lua_state());
+		}
+
+		void collect_garbage() {
+			lua_gc(lua_state(), LUA_GCCOLLECT, 0);
+		}
+
 		operator lua_State* () const {
 			return lua_state();
 		}