11 files changed, 916 insertions, 225 deletions

diff --git a/src/script/common/CMakeLists.txt b/src/script/common/CMakeLists.txt
index d07f6ab1b..3e84b46c7 100644
--- a/src/script/common/CMakeLists.txt
+++ b/src/script/common/CMakeLists.txt
@@ -3,6 +3,7 @@ set(common_SCRIPT_COMMON_SRCS
 	${CMAKE_CURRENT_SOURCE_DIR}/c_converter.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/c_types.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/c_internal.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/c_packer.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/helper.cpp
 	PARENT_SCOPE)
 
diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index 8a5a3fe71..166980025 100644
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -42,7 +42,7 @@ struct EnumString es_TileAnimationType[] =
 	{TAT_NONE, "none"},
 	{TAT_VERTICAL_FRAMES, "vertical_frames"},
 	{TAT_SHEET_2D, "sheet_2d"},
-	{0, NULL},
+	{0, nullptr},
 };
 
 /******************************************************************************/
@@ -198,7 +198,7 @@ void read_object_properties(lua_State *L, int index,
 		prop->hp_max = (u16)rangelim(hp_max, 0, U16_MAX);
 
 		if (prop->hp_max < sao->getHP()) {
-			PlayerHPChangeReason reason(PlayerHPChangeReason::SET_HP);
+			PlayerHPChangeReason reason(PlayerHPChangeReason::SET_HP_MAX);
 			sao->setHP(prop->hp_max, reason);
 		}
 	}
@@ -550,13 +550,6 @@ void read_content_features(lua_State *L, ContentFeatures &f, int index)
 
 	// tiles = {}
 	lua_getfield(L, index, "tiles");
-	// If nil, try the deprecated name "tile_images" instead
-	if(lua_isnil(L, -1)){
-		lua_pop(L, 1);
-		warn_if_field_exists(L, index, "tile_images",
-				"Deprecated; new name is \"tiles\".");
-		lua_getfield(L, index, "tile_images");
-	}
 	if(lua_istable(L, -1)){
 		int table = lua_gettop(L);
 		lua_pushnil(L);
@@ -613,13 +606,6 @@ void read_content_features(lua_State *L, ContentFeatures &f, int index)
 
 	// special_tiles = {}
 	lua_getfield(L, index, "special_tiles");
-	// If nil, try the deprecated name "special_materials" instead
-	if(lua_isnil(L, -1)){
-		lua_pop(L, 1);
-		warn_if_field_exists(L, index, "special_materials",
-				"Deprecated; new name is \"special_tiles\".");
-		lua_getfield(L, index, "special_materials");
-	}
 	if(lua_istable(L, -1)){
 		int table = lua_gettop(L);
 		lua_pushnil(L);
@@ -1000,22 +986,25 @@ void push_nodebox(lua_State *L, const NodeBox &box)
 			push_aabb3f(L, box.wall_side);
 			lua_setfield(L, -2, "wall_side");
 			break;
-		case NODEBOX_CONNECTED:
+		case NODEBOX_CONNECTED: {
 			lua_pushstring(L, "connected");
 			lua_setfield(L, -2, "type");
-			push_box(L, box.connect_top);
+			const auto &c = box.getConnected();
+			push_box(L, c.connect_top);
 			lua_setfield(L, -2, "connect_top");
-			push_box(L, box.connect_bottom);
+			push_box(L, c.connect_bottom);
 			lua_setfield(L, -2, "connect_bottom");
-			push_box(L, box.connect_front);
+			push_box(L, c.connect_front);
 			lua_setfield(L, -2, "connect_front");
-			push_box(L, box.connect_back);
+			push_box(L, c.connect_back);
 			lua_setfield(L, -2, "connect_back");
-			push_box(L, box.connect_left);
+			push_box(L, c.connect_left);
 			lua_setfield(L, -2, "connect_left");
-			push_box(L, box.connect_right);
+			push_box(L, c.connect_right);
 			lua_setfield(L, -2, "connect_right");
+			// half the boxes are missing here?
 			break;
+		}
 		default:
 			FATAL_ERROR("Invalid box.type");
 			break;
@@ -1048,22 +1037,26 @@ void push_palette(lua_State *L, const std::vector<video::SColor> *palette)
 
 /******************************************************************************/
 void read_server_sound_params(lua_State *L, int index,
-		ServerSoundParams &params)
+		ServerPlayingSound &params)
 {
 	if(index < 0)
 		index = lua_gettop(L) + 1 + index;
-	// Clear
-	params = ServerSoundParams();
+
 	if(lua_istable(L, index)){
+		// Functional overlap: this may modify SimpleSoundSpec contents
+		getfloatfield(L, index, "fade", params.spec.fade);
+		getfloatfield(L, index, "pitch", params.spec.pitch);
+		getboolfield(L, index, "loop", params.spec.loop);
+
 		getfloatfield(L, index, "gain", params.gain);
+
+		// Handle positional information
 		getstringfield(L, index, "to_player", params.to_player);
-		getfloatfield(L, index, "fade", params.fade);
-		getfloatfield(L, index, "pitch", params.pitch);
 		lua_getfield(L, index, "pos");
 		if(!lua_isnil(L, -1)){
 			v3f p = read_v3f(L, -1)*BS;
 			params.pos = p;
-			params.type = ServerSoundParams::SSP_POSITIONAL;
+			params.type = SoundLocation::Position;
 		}
 		lua_pop(L, 1);
 		lua_getfield(L, index, "object");
@@ -1072,13 +1065,12 @@ void read_server_sound_params(lua_State *L, int index,
 			ServerActiveObject *sao = ObjectRef::getobject(ref);
 			if(sao){
 				params.object = sao->getId();
-				params.type = ServerSoundParams::SSP_OBJECT;
+				params.type = SoundLocation::Object;
 			}
 		}
 		lua_pop(L, 1);
 		params.max_hear_distance = BS*getfloatfield_default(L, index,
 				"max_hear_distance", params.max_hear_distance/BS);
-		getboolfield(L, index, "loop", params.loop);
 		getstringfield(L, index, "exclude_player", params.exclude_player);
 	}
 }
@@ -1143,20 +1135,24 @@ NodeBox read_nodebox(lua_State *L, int index)
 	NODEBOXREAD(nodebox.wall_top, "wall_top");
 	NODEBOXREAD(nodebox.wall_bottom, "wall_bottom");
 	NODEBOXREAD(nodebox.wall_side, "wall_side");
-	NODEBOXREADVEC(nodebox.connect_top, "connect_top");
-	NODEBOXREADVEC(nodebox.connect_bottom, "connect_bottom");
-	NODEBOXREADVEC(nodebox.connect_front, "connect_front");
-	NODEBOXREADVEC(nodebox.connect_left, "connect_left");
-	NODEBOXREADVEC(nodebox.connect_back, "connect_back");
-	NODEBOXREADVEC(nodebox.connect_right, "connect_right");
-	NODEBOXREADVEC(nodebox.disconnected_top, "disconnected_top");
-	NODEBOXREADVEC(nodebox.disconnected_bottom, "disconnected_bottom");
-	NODEBOXREADVEC(nodebox.disconnected_front, "disconnected_front");
-	NODEBOXREADVEC(nodebox.disconnected_left, "disconnected_left");
-	NODEBOXREADVEC(nodebox.disconnected_back, "disconnected_back");
-	NODEBOXREADVEC(nodebox.disconnected_right, "disconnected_right");
-	NODEBOXREADVEC(nodebox.disconnected, "disconnected");
-	NODEBOXREADVEC(nodebox.disconnected_sides, "disconnected_sides");
+
+	if (nodebox.type == NODEBOX_CONNECTED) {
+		auto &c = nodebox.getConnected();
+		NODEBOXREADVEC(c.connect_top, "connect_top");
+		NODEBOXREADVEC(c.connect_bottom, "connect_bottom");
+		NODEBOXREADVEC(c.connect_front, "connect_front");
+		NODEBOXREADVEC(c.connect_left, "connect_left");
+		NODEBOXREADVEC(c.connect_back, "connect_back");
+		NODEBOXREADVEC(c.connect_right, "connect_right");
+		NODEBOXREADVEC(c.disconnected_top, "disconnected_top");
+		NODEBOXREADVEC(c.disconnected_bottom, "disconnected_bottom");
+		NODEBOXREADVEC(c.disconnected_front, "disconnected_front");
+		NODEBOXREADVEC(c.disconnected_left, "disconnected_left");
+		NODEBOXREADVEC(c.disconnected_back, "disconnected_back");
+		NODEBOXREADVEC(c.disconnected_right, "disconnected_right");
+		NODEBOXREADVEC(c.disconnected, "disconnected");
+		NODEBOXREADVEC(c.disconnected_sides, "disconnected_sides");
+	}
 
 	return nodebox;
 }
@@ -1351,22 +1347,27 @@ void push_tool_capabilities(lua_State *L,
 }
 
 /******************************************************************************/
-void push_inventory_list(lua_State *L, Inventory *inv, const char *name)
+void push_inventory_list(lua_State *L, const InventoryList &invlist)
 {
-	InventoryList *invlist = inv->getList(name);
-	if(invlist == NULL){
-		lua_pushnil(L);
-		return;
+	push_items(L, invlist.getItems());
+}
+
+/******************************************************************************/
+void push_inventory_lists(lua_State *L, const Inventory &inv)
+{
+	const auto &lists = inv.getLists();
+	lua_createtable(L, 0, lists.size());
+	for(const InventoryList *list : lists) {
+		const std::string &name = list->getName();
+		lua_pushlstring(L, name.c_str(), name.size());
+		push_inventory_list(L, *list);
+		lua_rawset(L, -3);
 	}
-	std::vector<ItemStack> items;
-	for(u32 i=0; i<invlist->getSize(); i++)
-		items.push_back(invlist->getItem(i));
-	push_items(L, items);
 }
 
 /******************************************************************************/
 void read_inventory_list(lua_State *L, int tableindex,
-		Inventory *inv, const char *name, Server* srv, int forcesize)
+		Inventory *inv, const char *name, IGameDef *gdef, int forcesize)
 {
 	if(tableindex < 0)
 		tableindex = lua_gettop(L) + 1 + tableindex;
@@ -1378,7 +1379,7 @@ void read_inventory_list(lua_State *L, int tableindex,
 	}
 
 	// Get Lua-specified items to insert into the list
-	std::vector<ItemStack> items = read_items(L, tableindex,srv);
+	std::vector<ItemStack> items = read_items(L, tableindex, gdef);
 	size_t listsize = (forcesize >= 0) ? forcesize : items.size();
 
 	// Create or resize/clear list
@@ -1630,7 +1631,7 @@ void push_items(lua_State *L, const std::vector<ItemStack> &items)
 }
 
 /******************************************************************************/
-std::vector<ItemStack> read_items(lua_State *L, int index, Server *srv)
+std::vector<ItemStack> read_items(lua_State *L, int index, IGameDef *gdef)
 {
 	if(index < 0)
 		index = lua_gettop(L) + 1 + index;
@@ -1646,7 +1647,7 @@ std::vector<ItemStack> read_items(lua_State *L, int index, Server *srv)
 		if (items.size() < (u32) key) {
 			items.resize(key);
 		}
-		items[key - 1] = read_item(L, -1, srv->idef());
+		items[key - 1] = read_item(L, -1, gdef->idef());
 		lua_pop(L, 1);
 	}
 	return items;
@@ -1697,24 +1698,19 @@ bool read_noiseparams(lua_State *L, int index, NoiseParams *np)
 void push_noiseparams(lua_State *L, NoiseParams *np)
 {
 	lua_newtable(L);
-	push_float_string(L, np->offset);
-	lua_setfield(L, -2, "offset");
-	push_float_string(L, np->scale);
-	lua_setfield(L, -2, "scale");
-	push_float_string(L, np->persist);
-	lua_setfield(L, -2, "persistence");
-	push_float_string(L, np->lacunarity);
-	lua_setfield(L, -2, "lacunarity");
-	lua_pushnumber(L, np->seed);
-	lua_setfield(L, -2, "seed");
-	lua_pushnumber(L, np->octaves);
-	lua_setfield(L, -2, "octaves");
+	setfloatfield(L, -1, "offset",      np->offset);
+	setfloatfield(L, -1, "scale",       np->scale);
+	setfloatfield(L, -1, "persist",     np->persist);
+	setfloatfield(L, -1, "persistence", np->persist);
+	setfloatfield(L, -1, "lacunarity",  np->lacunarity);
+	setintfield(  L, -1, "seed",        np->seed);
+	setintfield(  L, -1, "octaves",     np->octaves);
 
 	push_flags_string(L, flagdesc_noiseparams, np->flags,
 		np->flags);
 	lua_setfield(L, -2, "flags");
 
-	push_v3_float_string(L, np->spread);
+	push_v3f(L, np->spread);
 	lua_setfield(L, -2, "spread");
 }
 
@@ -1977,6 +1973,12 @@ void push_hud_element(lua_State *L, HudElement *elem)
 	lua_pushnumber(L, elem->number);
 	lua_setfield(L, -2, "number");
 
+	if (elem->type == HUD_ELEM_WAYPOINT) {
+		// waypoints reuse the item field to store precision, precision = item - 1
+		lua_pushnumber(L, elem->item - 1);
+		lua_setfield(L, -2, "precision");
+	}
+	// push the item field for waypoints as well for backwards compatibility
 	lua_pushnumber(L, elem->item);
 	lua_setfield(L, -2, "item");
 
@@ -2141,3 +2143,35 @@ void push_collision_move_result(lua_State *L, const collisionMoveResult &res)
 	lua_setfield(L, -2, "collisions");
 	/**/
 }
+
+
+void push_mod_spec(lua_State *L, const ModSpec &spec, bool include_unsatisfied)
+{
+	lua_newtable(L);
+
+	lua_pushstring(L, spec.name.c_str());
+	lua_setfield(L, -2, "name");
+
+	lua_pushstring(L, spec.author.c_str());
+	lua_setfield(L, -2, "author");
+
+	lua_pushinteger(L, spec.release);
+	lua_setfield(L, -2, "release");
+
+	lua_pushstring(L, spec.desc.c_str());
+	lua_setfield(L, -2, "description");
+
+	lua_pushstring(L, spec.path.c_str());
+	lua_setfield(L, -2, "path");
+
+	lua_pushstring(L, spec.virtual_path.c_str());
+	lua_setfield(L, -2, "virtual_path");
+
+	lua_newtable(L);
+	int i = 1;
+	for (const auto &dep : spec.unsatisfied_depends) {
+		lua_pushstring(L, dep.c_str());
+		lua_rawseti(L, -2, i++);
+	}
+	lua_setfield(L, -2, "unsatisfied_depends");
+}
diff --git a/src/script/common/c_content.h b/src/script/common/c_content.h
index e762604a4..ade3e4c1e 100644
--- a/src/script/common/c_content.h
+++ b/src/script/common/c_content.h
@@ -42,6 +42,7 @@ extern "C" {
 // We do a explicit path include because by default c_content.h include src/client/hud.h
 // prior to the src/hud.h, which is not good on server only build
 #include "../../hud.h"
+#include "content/mods.h"
 
 namespace Json { class Value; }
 
@@ -53,12 +54,13 @@ struct ItemDefinition;
 struct ToolCapabilities;
 struct ObjectProperties;
 struct SimpleSoundSpec;
-struct ServerSoundParams;
+struct ServerPlayingSound;
 class Inventory;
+class InventoryList;
 struct NodeBox;
 struct ContentFeatures;
 struct TileDef;
-class Server;
+class IGameDef;
 struct DigParams;
 struct HitParams;
 struct EnumString;
@@ -90,7 +92,7 @@ void               read_soundspec            (lua_State *L, int index,
 NodeBox            read_nodebox              (lua_State *L, int index);
 
 void               read_server_sound_params  (lua_State *L, int index,
-                                              ServerSoundParams &params);
+                                              ServerPlayingSound &params);
 
 void               push_dig_params           (lua_State *L,
                                               const DigParams &params);
@@ -120,11 +122,12 @@ void               push_object_properties    (lua_State *L,
                                               ObjectProperties *prop);
 
 void               push_inventory_list       (lua_State *L,
-                                              Inventory *inv,
-                                              const char *name);
+                                              const InventoryList &invlist);
+void               push_inventory_lists      (lua_State *L,
+                                              const Inventory &inv);
 void               read_inventory_list       (lua_State *L, int tableindex,
                                               Inventory *inv, const char *name,
-                                              Server *srv, int forcesize=-1);
+                                              IGameDef *gdef, int forcesize=-1);
 
 MapNode            readnode                  (lua_State *L, int index,
                                               const NodeDefManager *ndef);
@@ -164,7 +167,7 @@ void               push_items                (lua_State *L,
 
 std::vector<ItemStack> read_items            (lua_State *L,
                                               int index,
-                                              Server* srv);
+                                              IGameDef* gdef);
 
 void               push_soundspec            (lua_State *L,
                                               const SimpleSoundSpec &spec);
@@ -202,3 +205,5 @@ void push_hud_element          (lua_State *L, HudElement *elem);
 bool read_hud_change           (lua_State *L, HudElementStat &stat, HudElement *elem, void **value);
 
 void push_collision_move_result(lua_State *L, const collisionMoveResult &res);
+
+void push_mod_spec(lua_State *L, const ModSpec &spec, bool include_unsatisfied);
diff --git a/src/script/common/c_converter.cpp b/src/script/common/c_converter.cpp
index 7898b197d..69da35b73 100644
--- a/src/script/common/c_converter.cpp
+++ b/src/script/common/c_converter.cpp
@@ -18,8 +18,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 */
 
 extern "C" {
-#include "lua.h"
-#include "lauxlib.h"
+#include <lua.h>
+#include <lauxlib.h>
 }
 
 #include "util/numeric.h"
@@ -29,55 +29,52 @@ extern "C" {
 #include "common/c_internal.h"
 #include "constants.h"
 #include <set>
+#include <cmath>
 
 
-#define CHECK_TYPE(index, name, type) { \
+#define CHECK_TYPE(index, name, type) do { \
 		int t = lua_type(L, (index)); \
 		if (t != (type)) { \
 			throw LuaError(std::string("Invalid ") + (name) + \
 				" (expected " + lua_typename(L, (type)) + \
 				" got " + lua_typename(L, t) + ")."); \
 		} \
-	}
-#define CHECK_POS_COORD(name) CHECK_TYPE(-1, "position coordinate '" name "'", LUA_TNUMBER)
-#define CHECK_FLOAT_RANGE(value, name) \
-if (value < F1000_MIN || value > F1000_MAX) { \
-	std::ostringstream error_text; \
-	error_text << "Invalid float vector dimension range '" name "' " << \
-	"(expected " << F1000_MIN << " < " name " < " << F1000_MAX << \
-	" got " << value << ")." << std::endl; \
-	throw LuaError(error_text.str()); \
-}
-#define CHECK_POS_TAB(index) CHECK_TYPE(index, "position", LUA_TTABLE)
+	} while(0)
+
+#define CHECK_FLOAT(value, name) do {\
+		if (std::isnan(value) || std::isinf(value)) { \
+			throw LuaError("Invalid float value for '" name \
+				"' (NaN or infinity)"); \
+		} \
+	} while (0)
+
+#define CHECK_POS_COORD(name) CHECK_TYPE(-1, "vector coordinate " name, LUA_TNUMBER)
+#define CHECK_POS_TAB(index) CHECK_TYPE(index, "vector", LUA_TTABLE)
 
 
 /**
- * A helper which sets (if available) the vector metatable from builtin as metatable
- * for the table on top of the stack
+ * A helper which sets the vector metatable for the table on top of the stack
  */
 static void set_vector_metatable(lua_State *L)
 {
-	// get vector.metatable
-	lua_getglobal(L, "vector");
-	if (!lua_istable(L, -1)) {
-		// there is no global vector table
-		lua_pop(L, 1);
-		errorstream << "set_vector_metatable in c_converter.cpp: " <<
-				"missing global vector table" << std::endl;
-		return;
-	}
-	lua_getfield(L, -1, "metatable");
-	// set the metatable
-	lua_setmetatable(L, -3);
-	// pop vector global
-	lua_pop(L, 1);
+	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_VECTOR_METATABLE);
+	lua_setmetatable(L, -2);
 }
 
-
-void push_float_string(lua_State *L, float value)
+// Retrieve an integer vector where all components are optional
+template<class T>
+static bool getv3intfield(lua_State *L, int index,
+		const char *fieldname, T &result)
 {
-	auto str = ftos(value);
-	lua_pushstring(L, str.c_str());
+	lua_getfield(L, index, fieldname);
+	bool got = false;
+	if (lua_istable(L, -1)) {
+		got |= getintfield(L, -1, "x", result.X);
+		got |= getintfield(L, -1, "y", result.Y);
+		got |= getintfield(L, -1, "z", result.Z);
+	}
+	lua_pop(L, 1);
+	return got;
 }
 
 void push_v3f(lua_State *L, v3f p)
@@ -101,26 +98,6 @@ void push_v2f(lua_State *L, v2f p)
 	lua_setfield(L, -2, "y");
 }
 
-void push_v3_float_string(lua_State *L, v3f p)
-{
-	lua_createtable(L, 0, 3);
-	push_float_string(L, p.X);
-	lua_setfield(L, -2, "x");
-	push_float_string(L, p.Y);
-	lua_setfield(L, -2, "y");
-	push_float_string(L, p.Z);
-	lua_setfield(L, -2, "z");
-}
-
-void push_v2_float_string(lua_State *L, v2f p)
-{
-	lua_createtable(L, 0, 2);
-	push_float_string(L, p.X);
-	lua_setfield(L, -2, "x");
-	push_float_string(L, p.Y);
-	lua_setfield(L, -2, "y");
-}
-
 v2s16 read_v2s16(lua_State *L, int index)
 {
 	v2s16 p;
@@ -185,10 +162,12 @@ v2f check_v2f(lua_State *L, int index)
 	lua_getfield(L, index, "x");
 	CHECK_POS_COORD("x");
 	p.X = lua_tonumber(L, -1);
+	CHECK_FLOAT(p.X, "x");
 	lua_pop(L, 1);
 	lua_getfield(L, index, "y");
 	CHECK_POS_COORD("y");
 	p.Y = lua_tonumber(L, -1);
+	CHECK_FLOAT(p.Y, "y");
 	lua_pop(L, 1);
 	return p;
 }
@@ -216,17 +195,17 @@ v3f check_v3f(lua_State *L, int index)
 	lua_getfield(L, index, "x");
 	CHECK_POS_COORD("x");
 	pos.X = lua_tonumber(L, -1);
-	CHECK_FLOAT_RANGE(pos.X, "x")
+	CHECK_FLOAT(pos.X, "x");
 	lua_pop(L, 1);
 	lua_getfield(L, index, "y");
 	CHECK_POS_COORD("y");
 	pos.Y = lua_tonumber(L, -1);
-	CHECK_FLOAT_RANGE(pos.Y, "y")
+	CHECK_FLOAT(pos.Y, "y");
 	lua_pop(L, 1);
 	lua_getfield(L, index, "z");
 	CHECK_POS_COORD("z");
 	pos.Z = lua_tonumber(L, -1);
-	CHECK_FLOAT_RANGE(pos.Z, "z")
+	CHECK_FLOAT(pos.Z, "z");
 	lua_pop(L, 1);
 	return pos;
 }
@@ -254,17 +233,17 @@ v3d check_v3d(lua_State *L, int index)
 	lua_getfield(L, index, "x");
 	CHECK_POS_COORD("x");
 	pos.X = lua_tonumber(L, -1);
-	CHECK_FLOAT_RANGE(pos.X, "x")
+	CHECK_FLOAT(pos.X, "x");
 	lua_pop(L, 1);
 	lua_getfield(L, index, "y");
 	CHECK_POS_COORD("y");
 	pos.Y = lua_tonumber(L, -1);
-	CHECK_FLOAT_RANGE(pos.Y, "y")
+	CHECK_FLOAT(pos.Y, "y");
 	lua_pop(L, 1);
 	lua_getfield(L, index, "z");
 	CHECK_POS_COORD("z");
 	pos.Z = lua_tonumber(L, -1);
-	CHECK_FLOAT_RANGE(pos.Z, "z")
+	CHECK_FLOAT(pos.Z, "z");
 	lua_pop(L, 1);
 	return pos;
 }
diff --git a/src/script/common/c_converter.h b/src/script/common/c_converter.h
index 6ad6f3212..2af726d16 100644
--- a/src/script/common/c_converter.h
+++ b/src/script/common/c_converter.h
@@ -61,23 +61,10 @@ bool getintfield(lua_State *L, int table,
 	return got;
 }
 
-template<class T>
-bool getv3intfield(lua_State *L, int index,
-		const char *fieldname, T &result)
-{
-	lua_getfield(L, index, fieldname);
-	bool got = false;
-	if (lua_istable(L, -1)) {
-		got |= getintfield(L, -1, "x", result.X);
-		got |= getintfield(L, -1, "y", result.Y);
-		got |= getintfield(L, -1, "z", result.Z);
-	}
-	lua_pop(L, 1);
-	return got;
-}
-
+// Retrieve an v3s16 where all components are optional (falls back to default)
 v3s16              getv3s16field_default(lua_State *L, int table,
                              const char *fieldname, v3s16 default_);
+
 bool               getstringfield(lua_State *L, int table,
                              const char *fieldname, std::string &result);
 size_t             getstringlistfield(lua_State *L, int table,
@@ -100,6 +87,7 @@ void               setboolfield(lua_State *L, int table,
                              const char *fieldname, bool value);
 
 v3f                 checkFloatPos       (lua_State *L, int index);
+v2f                 check_v2f           (lua_State *L, int index);
 v3f                 check_v3f           (lua_State *L, int index);
 v3s16               check_v3s16         (lua_State *L, int index);
 
@@ -118,9 +106,6 @@ std::vector<aabb3f> read_aabb3f_vector  (lua_State *L, int index, f32 scale);
 size_t              read_stringlist     (lua_State *L, int index,
                                          std::vector<std::string> *result);
 
-void                push_float_string   (lua_State *L, float value);
-void                push_v3_float_string(lua_State *L, v3f p);
-void                push_v2_float_string(lua_State *L, v2f p);
 void                push_v2s16          (lua_State *L, v2s16 p);
 void                push_v2s32          (lua_State *L, v2s32 p);
 void                push_v3s16          (lua_State *L, v3s16 p);
diff --git a/src/script/common/c_internal.cpp b/src/script/common/c_internal.cpp
index df82dba14..ddd2d184c 100644
--- a/src/script/common/c_internal.cpp
+++ b/src/script/common/c_internal.cpp
@@ -166,3 +166,17 @@ void log_deprecated(lua_State *L, std::string message, int stack_depth)
 		infostream << script_get_backtrace(L) << std::endl;
 }
 
+void call_string_dump(lua_State *L, int idx)
+{
+	// Retrieve string.dump from insecure env to avoid it being tampered with
+	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_GLOBALS_BACKUP);
+	if (!lua_isnil(L, -1))
+		lua_getfield(L, -1, "string");
+	else
+		lua_getglobal(L, "string");
+	lua_getfield(L, -1, "dump");
+	lua_remove(L, -2); // remove _G
+	lua_remove(L, -2); // remove 'string' table
+	lua_pushvalue(L, idx);
+	lua_call(L, 1, 1);
+}
diff --git a/src/script/common/c_internal.h b/src/script/common/c_internal.h
index 94cfd61fb..272a39941 100644
--- a/src/script/common/c_internal.h
+++ b/src/script/common/c_internal.h
@@ -55,6 +55,8 @@ extern "C" {
 #define CUSTOM_RIDX_CURRENT_MOD_NAME    (CUSTOM_RIDX_BASE + 2)
 #define CUSTOM_RIDX_BACKTRACE           (CUSTOM_RIDX_BASE + 3)
 #define CUSTOM_RIDX_HTTP_API_LUA        (CUSTOM_RIDX_BASE + 4)
+#define CUSTOM_RIDX_VECTOR_METATABLE    (CUSTOM_RIDX_BASE + 5)
+#define CUSTOM_RIDX_METATABLE_MAP       (CUSTOM_RIDX_BASE + 6)
 
 
 // Determine if CUSTOM_RIDX_SCRIPTAPI will hold a light or full userdata
@@ -138,3 +140,7 @@ DeprecatedHandlingMode get_deprecated_handling_mode();
  * @param stack_depth How far on the stack to the first user function (ie: not builtin or core)
  */
 void log_deprecated(lua_State *L, std::string message, int stack_depth = 1);
+
+// Safely call string.dump on a function value
+// (does not pop, leaves one value on stack)
+void call_string_dump(lua_State *L, int idx);
diff --git a/src/script/common/c_packer.cpp b/src/script/common/c_packer.cpp
new file mode 100644
index 000000000..597f5e447
--- /dev/null
+++ b/src/script/common/c_packer.cpp
@@ -0,0 +1,596 @@
+/*
+Minetest
+Copyright (C) 2022 sfan5 <sfan5@live.de>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include <cstdio>
+#include <cstring>
+#include <cmath>
+#include <cassert>
+#include <unordered_set>
+#include <unordered_map>
+#include "c_packer.h"
+#include "c_internal.h"
+#include "log.h"
+#include "debug.h"
+#include "threading/mutex_auto_lock.h"
+
+extern "C" {
+#include <lauxlib.h>
+}
+
+//
+// Helpers
+//
+
+// convert negative index to absolute position on Lua stack
+static inline int absidx(lua_State *L, int idx)
+{
+	assert(idx < 0);
+	return lua_gettop(L) + idx + 1;
+}
+
+// does the type put anything into PackedInstr::sdata?
+static inline bool uses_sdata(int type)
+{
+	switch (type) {
+		case LUA_TSTRING:
+		case LUA_TFUNCTION:
+		case LUA_TUSERDATA:
+			return true;
+		default:
+			return false;
+	}
+}
+
+// does the type put anything into PackedInstr::<union>?
+static inline bool uses_union(int type)
+{
+	switch (type) {
+		case LUA_TNIL:
+		case LUA_TSTRING:
+		case LUA_TFUNCTION:
+			return false;
+		default:
+			return true;
+	}
+}
+
+static inline bool can_set_into(int ktype, int vtype)
+{
+	switch (ktype) {
+		case LUA_TNUMBER:
+			return !uses_union(vtype);
+		case LUA_TSTRING:
+			return !uses_sdata(vtype);
+		default:
+			return false;
+	}
+}
+
+// is the key suitable for use with set_into?
+static inline bool suitable_key(lua_State *L, int idx)
+{
+	if (lua_type(L, idx) == LUA_TSTRING) {
+		// strings may not have a NULL byte (-> lua_setfield)
+		size_t len;
+		const char *str = lua_tolstring(L, idx, &len);
+		return strlen(str) == len;
+	} else {
+		assert(lua_type(L, idx) == LUA_TNUMBER);
+		// numbers must fit into an s32 and be integers (-> lua_rawseti)
+		lua_Number n = lua_tonumber(L, idx);
+		return std::floor(n) == n && n >= S32_MIN && n <= S32_MAX;
+	}
+}
+
+namespace {
+	// checks if you left any values on the stack, for debugging
+	class StackChecker {
+		lua_State *L;
+		int top;
+	public:
+		StackChecker(lua_State *L) : L(L), top(lua_gettop(L)) {}
+		~StackChecker() {
+			assert(lua_gettop(L) >= top);
+			if (lua_gettop(L) > top) {
+				rawstream << "Lua stack not cleaned up: "
+					<< lua_gettop(L) << " != " << top
+					<< " (false-positive if exception thrown)" << std::endl;
+			}
+		}
+	};
+
+	// Since an std::vector may reallocate, this is the only safe way to keep
+	// a reference to a particular element.
+	template <typename T>
+	class VectorRef {
+		std::vector<T> *vec;
+		size_t idx;
+		VectorRef(std::vector<T> *vec, size_t idx) : vec(vec), idx(idx) {}
+	public:
+		constexpr VectorRef() : vec(nullptr), idx(0) {}
+		static VectorRef<T> front(std::vector<T> &vec) {
+			return VectorRef(&vec, 0);
+		}
+		static VectorRef<T> back(std::vector<T> &vec) {
+			return VectorRef(&vec, vec.size() - 1);
+		}
+		T &operator*() { return (*vec)[idx]; }
+		T *operator->() { return &(*vec)[idx]; }
+		operator bool() const { return vec != nullptr; }
+	};
+
+	struct Packer {
+		PackInFunc fin;
+		PackOutFunc fout;
+	};
+
+	typedef std::pair<std::string, Packer> PackerTuple;
+}
+
+static inline auto emplace(PackedValue &pv, s16 type)
+{
+	pv.i.emplace_back();
+	auto ref = VectorRef<PackedInstr>::back(pv.i);
+	ref->type = type;
+	// Initialize fields that may be left untouched
+	if (type == LUA_TTABLE) {
+		ref->uidata1 = 0;
+		ref->uidata2 = 0;
+	} else if (type == LUA_TUSERDATA) {
+		ref->ptrdata = nullptr;
+	} else if (type == INSTR_POP) {
+		ref->sidata2 = 0;
+	}
+	return ref;
+}
+
+//
+// Management of registered packers
+//
+
+static std::unordered_map<std::string, Packer> g_packers;
+static std::mutex g_packers_lock;
+
+void script_register_packer(lua_State *L, const char *regname,
+	PackInFunc fin, PackOutFunc fout)
+{
+	// Store away callbacks
+	{
+		MutexAutoLock autolock(g_packers_lock);
+		auto it = g_packers.find(regname);
+		if (it == g_packers.end()) {
+			auto &ref = g_packers[regname];
+			ref.fin = fin;
+			ref.fout = fout;
+		} else {
+			FATAL_ERROR_IF(it->second.fin != fin || it->second.fout != fout,
+				"Packer registered twice with mismatching callbacks");
+		}
+	}
+
+	// Save metatable so we can identify instances later
+	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_METATABLE_MAP);
+	if (lua_isnil(L, -1)) {
+		lua_newtable(L);
+		lua_pushvalue(L, -1);
+		lua_rawseti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_METATABLE_MAP);
+	}
+
+	luaL_getmetatable(L, regname);
+	FATAL_ERROR_IF(lua_isnil(L, -1), "No metatable registered with that name");
+
+	// CUSTOM_RIDX_METATABLE_MAP contains { [metatable] = "regname", ... }
+	// check first
+	lua_pushstring(L, regname);
+	lua_rawget(L, -3);
+	if (!lua_isnil(L, -1)) {
+		FATAL_ERROR_IF(lua_topointer(L, -1) != lua_topointer(L, -2),
+				"Packer registered twice with inconsistent metatable");
+	}
+	lua_pop(L, 1);
+	// then set
+	lua_pushstring(L, regname);
+	lua_rawset(L, -3);
+
+	lua_pop(L, 1);
+}
+
+static bool find_packer(const char *regname, PackerTuple &out)
+{
+	MutexAutoLock autolock(g_packers_lock);
+	auto it = g_packers.find(regname);
+	if (it == g_packers.end())
+		return false;
+	// copy data for thread safety
+	out.first = it->first;
+	out.second = it->second;
+	return true;
+}
+
+static bool find_packer(lua_State *L, int idx, PackerTuple &out)
+{
+#ifndef NDEBUG
+	StackChecker checker(L);
+#endif
+
+	// retrieve metatable of the object
+	if (lua_getmetatable(L, idx) != 1)
+		return false;
+
+	// use our global table to map it to the registry name
+	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_METATABLE_MAP);
+	assert(lua_istable(L, -1));
+	lua_pushvalue(L, -2);
+	lua_rawget(L, -2);
+	if (lua_isnil(L, -1)) {
+		lua_pop(L, 3);
+		return false;
+	}
+
+	// load the associated data
+	bool found = find_packer(lua_tostring(L, -1), out);
+	FATAL_ERROR_IF(!found, "Inconsistent internal state");
+	lua_pop(L, 3);
+	return true;
+}
+
+//
+// Packing implementation
+//
+
+static VectorRef<PackedInstr> record_object(lua_State *L, int idx, PackedValue &pv,
+		std::unordered_map<const void *, s32> &seen)
+{
+	const void *ptr = lua_topointer(L, idx);
+	assert(ptr);
+	auto found = seen.find(ptr);
+	if (found == seen.end()) {
+		seen[ptr] = pv.i.size();
+		return VectorRef<PackedInstr>();
+	}
+	s32 ref = found->second;
+	assert(ref < (s32)pv.i.size());
+	// reuse the value from first time
+	auto r = emplace(pv, INSTR_PUSHREF);
+	r->ref = ref;
+	pv.i[ref].keep_ref = true;
+	return r;
+}
+
+static VectorRef<PackedInstr> pack_inner(lua_State *L, int idx, int vidx, PackedValue &pv,
+		std::unordered_map<const void *, s32> &seen)
+{
+#ifndef NDEBUG
+	StackChecker checker(L);
+	assert(idx > 0);
+	assert(vidx > 0);
+#endif
+
+	switch (lua_type(L, idx)) {
+		case LUA_TNONE:
+		case LUA_TNIL:
+			return emplace(pv, LUA_TNIL);
+		case LUA_TBOOLEAN: {
+			auto r = emplace(pv, LUA_TBOOLEAN);
+			r->bdata = lua_toboolean(L, idx);
+			return r;
+		}
+		case LUA_TNUMBER: {
+			auto r = emplace(pv, LUA_TNUMBER);
+			r->ndata = lua_tonumber(L, idx);
+			return r;
+		}
+		case LUA_TSTRING: {
+			auto r = emplace(pv, LUA_TSTRING);
+			size_t len;
+			const char *str = lua_tolstring(L, idx, &len);
+			assert(str);
+			r->sdata.assign(str, len);
+			return r;
+		}
+		case LUA_TTABLE: {
+			auto r = record_object(L, idx, pv, seen);
+			if (r)
+				return r;
+			break; // execution continues
+		}
+		case LUA_TFUNCTION: {
+			auto r = record_object(L, idx, pv, seen);
+			if (r)
+				return r;
+			r = emplace(pv, LUA_TFUNCTION);
+			call_string_dump(L, idx);
+			size_t len;
+			const char *str = lua_tolstring(L, -1, &len);
+			assert(str);
+			r->sdata.assign(str, len);
+			lua_pop(L, 1);
+			return r;
+		}
+		case LUA_TUSERDATA: {
+			auto r = record_object(L, idx, pv, seen);
+			if (r)
+				return r;
+			PackerTuple ser;
+			if (!find_packer(L, idx, ser))
+				throw LuaError("Cannot serialize unsupported userdata");
+			pv.contains_userdata = true;
+			r = emplace(pv, LUA_TUSERDATA);
+			r->sdata = ser.first;
+			r->ptrdata = ser.second.fin(L, idx);
+			return r;
+		}
+		default: {
+			std::string err = "Cannot serialize type ";
+			err += lua_typename(L, lua_type(L, idx));
+			throw LuaError(err);
+		}
+	}
+
+	// LUA_TTABLE
+	lua_checkstack(L, 5);
+
+	auto rtable = emplace(pv, LUA_TTABLE);
+	const int vi_table = vidx++;
+
+	lua_pushnil(L);
+	while (lua_next(L, idx) != 0) {
+		// key at -2, value at -1
+		const int ktype = lua_type(L, -2), vtype = lua_type(L, -1);
+		if (ktype == LUA_TNUMBER)
+			rtable->uidata1++; // narr
+		else
+			rtable->uidata2++; // nrec
+
+		// check if we can use a shortcut
+		if (can_set_into(ktype, vtype) && suitable_key(L, -2)) {
+			// push only the value
+			auto rval = pack_inner(L, absidx(L, -1), vidx, pv, seen);
+			rval->pop = rval->type != LUA_TTABLE;
+			// and where to put it:
+			rval->set_into = vi_table;
+			if (ktype == LUA_TSTRING)
+				rval->sdata = lua_tostring(L, -2);
+			else
+				rval->sidata1 = lua_tointeger(L, -2);
+			// pop tables after the fact
+			if (!rval->pop) {
+				auto ri1 = emplace(pv, INSTR_POP);
+				ri1->sidata1 = vidx;
+			}
+		} else {
+			// push the key and value
+			pack_inner(L, absidx(L, -2), vidx, pv, seen);
+			vidx++;
+			pack_inner(L, absidx(L, -1), vidx, pv, seen);
+			vidx++;
+			// push an instruction to set them
+			auto ri1 = emplace(pv, INSTR_SETTABLE);
+			ri1->set_into = vi_table;
+			ri1->sidata1 = vidx - 2;
+			ri1->sidata2 = vidx - 1;
+			ri1->pop = true;
+			vidx -= 2;
+		}
+
+		lua_pop(L, 1);
+	}
+
+	assert(vidx == vi_table + 1);
+	return rtable;
+}
+
+PackedValue *script_pack(lua_State *L, int idx)
+{
+	if (idx < 0)
+		idx = absidx(L, idx);
+
+	PackedValue pv;
+	std::unordered_map<const void *, s32> seen;
+	pack_inner(L, idx, 1, pv, seen);
+
+	return new PackedValue(std::move(pv));
+}
+
+//
+// Unpacking implementation
+//
+
+void script_unpack(lua_State *L, PackedValue *pv)
+{
+	lua_newtable(L); // table at index top to track ref indices -> objects
+	const int top = lua_gettop(L);
+	int ctr = 0;
+
+	for (size_t packed_idx = 0; packed_idx < pv->i.size(); packed_idx++) {
+		auto &i = pv->i[packed_idx];
+
+		// If leaving values on stack make sure there's space (every 5th iteration)
+		if (!i.pop && (ctr++) >= 5) {
+			lua_checkstack(L, 5);
+			ctr = 0;
+		}
+
+		switch (i.type) {
+			/* Instructions */
+			case INSTR_SETTABLE:
+				lua_pushvalue(L, top + i.sidata1); // key
+				lua_pushvalue(L, top + i.sidata2); // value
+				lua_rawset(L, top + i.set_into);
+				if (i.pop) {
+					if (i.sidata1 != i.sidata2) {
+						// removing moves indices so pop higher index first
+						lua_remove(L, top + std::max(i.sidata1, i.sidata2));
+						lua_remove(L, top + std::min(i.sidata1, i.sidata2));
+					} else {
+						lua_remove(L, top + i.sidata1);
+					}
+				}
+				continue;
+			case INSTR_POP:
+				lua_remove(L, top + i.sidata1);
+				if (i.sidata2 > 0)
+					lua_remove(L, top + i.sidata2);
+				continue;
+			case INSTR_PUSHREF:
+				lua_pushinteger(L, i.ref);
+				lua_rawget(L, top);
+				break;
+
+			/* Lua types */
+			case LUA_TNIL:
+				lua_pushnil(L);
+				break;
+			case LUA_TBOOLEAN:
+				lua_pushboolean(L, i.bdata);
+				break;
+			case LUA_TNUMBER:
+				lua_pushnumber(L, i.ndata);
+				break;
+			case LUA_TSTRING:
+				lua_pushlstring(L, i.sdata.data(), i.sdata.size());
+				break;
+			case LUA_TTABLE:
+				lua_createtable(L, i.uidata1, i.uidata2);
+				break;
+			case LUA_TFUNCTION:
+				luaL_loadbuffer(L, i.sdata.data(), i.sdata.size(), nullptr);
+				break;
+			case LUA_TUSERDATA: {
+				PackerTuple ser;
+				sanity_check(find_packer(i.sdata.c_str(), ser));
+				ser.second.fout(L, i.ptrdata);
+				i.ptrdata = nullptr; // ownership taken by callback
+				break;
+			}
+
+			default:
+				assert(0);
+				break;
+		}
+
+		if (i.keep_ref) {
+			lua_pushinteger(L, packed_idx);
+			lua_pushvalue(L, -2);
+			lua_rawset(L, top);
+		}
+
+		if (i.set_into) {
+			if (!i.pop)
+				lua_pushvalue(L, -1);
+			if (uses_sdata(i.type))
+				lua_rawseti(L, top + i.set_into, i.sidata1);
+			else
+				lua_setfield(L, top + i.set_into, i.sdata.c_str());
+		} else {
+			if (i.pop)
+				lua_pop(L, 1);
+		}
+	}
+
+	// as part of the unpacking process we take ownership of all userdata
+	pv->contains_userdata = false;
+	// leave exactly one value on the stack
+	lua_settop(L, top+1);
+	lua_remove(L, top);
+}
+
+//
+// PackedValue
+//
+
+PackedValue::~PackedValue()
+{
+	if (!contains_userdata)
+		return;
+	for (auto &i : this->i) {
+		if (i.type == LUA_TUSERDATA && i.ptrdata) {
+			PackerTuple ser;
+			if (find_packer(i.sdata.c_str(), ser)) {
+				// tell it to deallocate object
+				ser.second.fout(nullptr, i.ptrdata);
+			} else {
+				assert(false);
+			}
+		}
+	}
+}
+
+//
+// script_dump_packed
+//
+
+#ifndef NDEBUG
+void script_dump_packed(const PackedValue *val)
+{
+	printf("instruction stream: [\n");
+	for (const auto &i : val->i) {
+		printf("\t(");
+		switch (i.type) {
+			case INSTR_SETTABLE:
+				printf("SETTABLE(%d, %d)", i.sidata1, i.sidata2);
+				break;
+			case INSTR_POP:
+				printf(i.sidata2 ? "POP(%d, %d)" : "POP(%d)", i.sidata1, i.sidata2);
+				break;
+			case INSTR_PUSHREF:
+				printf("PUSHREF(%d)", i.ref);
+				break;
+			case LUA_TNIL:
+				printf("nil");
+				break;
+			case LUA_TBOOLEAN:
+				printf(i.bdata ? "true" : "false");
+				break;
+			case LUA_TNUMBER:
+				printf("%f", i.ndata);
+				break;
+			case LUA_TSTRING:
+				printf("\"%s\"", i.sdata.c_str());
+				break;
+			case LUA_TTABLE:
+				printf("table(%d, %d)", i.uidata1, i.uidata2);
+				break;
+			case LUA_TFUNCTION:
+				printf("function(%lu byte)", i.sdata.size());
+				break;
+			case LUA_TUSERDATA:
+				printf("userdata %s %p", i.sdata.c_str(), i.ptrdata);
+				break;
+			default:
+				printf("!!UNKNOWN!!");
+				break;
+		}
+		if (i.set_into) {
+			if (i.type >= 0 && uses_sdata(i.type))
+				printf(", k=%d, into=%d", i.sidata1, i.set_into);
+			else if (i.type >= 0)
+				printf(", k=\"%s\", into=%d", i.sdata.c_str(), i.set_into);
+			else
+				printf(", into=%d", i.set_into);
+		}
+		if (i.keep_ref)
+			printf(", keep_ref");
+		if (i.pop)
+			printf(", pop");
+		printf(")\n");
+	}
+	printf("]\n");
+}
+#endif
diff --git a/src/script/common/c_packer.h b/src/script/common/c_packer.h
new file mode 100644
index 000000000..fe072c10a
--- /dev/null
+++ b/src/script/common/c_packer.h
@@ -0,0 +1,126 @@
+/*
+Minetest
+Copyright (C) 2022 sfan5 <sfan5@live.de>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#pragma once
+
+#include <string>
+#include <vector>
+#include "irrlichttypes.h"
+#include "util/basic_macros.h"
+
+extern "C" {
+#include <lua.h>
+}
+
+/*
+	This file defines an in-memory representation of Lua objects including
+	support for functions and userdata. It it used to move data between Lua
+	states and cannot be used for persistence or network transfer.
+*/
+
+#define INSTR_SETTABLE (-10)
+#define INSTR_POP      (-11)
+#define INSTR_PUSHREF  (-12)
+
+/**
+ * Represents a single instruction that pushes a new value or works with existing ones.
+ */
+struct PackedInstr
+{
+	s16 type; // LUA_T* or INSTR_*
+	u16 set_into; // set into table on stack
+	bool keep_ref; // is referenced later by INSTR_PUSHREF?
+	bool pop; // remove from stack?
+	union {
+		bool bdata; // boolean: value
+		lua_Number ndata; // number: value
+		struct {
+			u16 uidata1, uidata2; // table: narr, nrec
+		};
+		struct {
+			/*
+				SETTABLE: key index, value index
+				POP: indices to remove
+				otherwise w/ set_into: numeric key, -
+			*/
+			s32 sidata1, sidata2;
+		};
+		void *ptrdata; // userdata: implementation defined
+		s32 ref; // PUSHREF: index of referenced instr
+	};
+	/*
+		- string: value
+		- function: buffer
+		- w/ set_into: string key (no null bytes!)
+		- userdata: name in registry
+	*/
+	std::string sdata;
+
+	PackedInstr() : type(0), set_into(0), keep_ref(false), pop(false) {}
+};
+
+/**
+ * A packed value can be a primitive like a string or number but also a table
+ * including all of its contents. It is made up of a linear stream of
+ * 'instructions' that build the final value when executed.
+ */
+struct PackedValue
+{
+	std::vector<PackedInstr> i;
+	// Indicates whether there are any userdata pointers that need to be deallocated
+	bool contains_userdata = false;
+
+	PackedValue() = default;
+	~PackedValue();
+
+	DISABLE_CLASS_COPY(PackedValue)
+
+	ALLOW_CLASS_MOVE(PackedValue)
+};
+
+/*
+ * Packing callback: Turns a Lua value at given index into a void*
+ */
+typedef void *(*PackInFunc)(lua_State *L, int idx);
+/*
+ * Unpacking callback: Turns a void* back into the Lua value (left on top of stack)
+ *
+ * Note that this function must take ownership of the pointer, so make sure
+ * to free or keep the memory.
+ * `L` can be nullptr to indicate that data should just be discarded.
+ */
+typedef void (*PackOutFunc)(lua_State *L, void *ptr);
+/*
+ * Register a packable type with the name of its metatable.
+ *
+ * Even though the callbacks are global this must be called for every Lua state
+ * that supports objects of this type.
+ * This function is thread-safe.
+ */
+void script_register_packer(lua_State *L, const char *regname,
+		PackInFunc fin, PackOutFunc fout);
+
+// Pack a Lua value
+PackedValue *script_pack(lua_State *L, int idx);
+// Unpack a Lua value (left on top of stack)
+// Note that this may modify the PackedValue, reusability is not guaranteed!
+void script_unpack(lua_State *L, PackedValue *val);
+
+// Dump contents of PackedValue to stdout for debugging
+void script_dump_packed(const PackedValue *val);
diff --git a/src/script/common/helper.cpp b/src/script/common/helper.cpp
index fbf24e1b7..72de2b14a 100644
--- a/src/script/common/helper.cpp
+++ b/src/script/common/helper.cpp
@@ -17,35 +17,16 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
+extern "C" {
+#include <lauxlib.h>
+}
+
 #include "helper.h"
 #include <cmath>
-#include <sstream>
 #include <irr_v2d.h>
 #include <irr_v3d.h>
+#include "c_converter.h"
 #include "c_types.h"
-#include "c_internal.h"
-
-// imported from c_converter.cpp with pure C++ style
-static inline void check_lua_type(lua_State *L, int index, const char *name, int type)
-{
-	int t = lua_type(L, index);
-	if (t != type) {
-		std::string traceback = script_get_backtrace(L);
-		throw LuaError(std::string("Invalid ") + (name) + " (expected " +
-				lua_typename(L, (type)) + " got " + lua_typename(L, t) +
-				").\n" + traceback);
-	}
-}
-
-// imported from c_converter.cpp
-#define CHECK_POS_COORD(name)                                                            \
-	check_lua_type(L, -1, "position coordinate '" name "'", LUA_TNUMBER)
-#define CHECK_POS_TAB(index) check_lua_type(L, index, "position", LUA_TTABLE)
-
-bool LuaHelper::isNaN(lua_State *L, int idx)
-{
-	return lua_type(L, idx) == LUA_TNUMBER && std::isnan(lua_tonumber(L, idx));
-}
 
 /*
  * Read template functions
@@ -59,74 +40,41 @@ bool LuaHelper::readParam(lua_State *L, int index)
 template <>
 s16 LuaHelper::readParam(lua_State *L, int index)
 {
-	return lua_tonumber(L, index);
+	return luaL_checkinteger(L, index);
 }
 
 template <>
 int LuaHelper::readParam(lua_State *L, int index)
 {
-	return luaL_checkint(L, index);
+	return luaL_checkinteger(L, index);
 }
 
 template <>
 float LuaHelper::readParam(lua_State *L, int index)
 {
-	if (isNaN(L, index))
-		throw LuaError("NaN value is not allowed.");
+	lua_Number v = luaL_checknumber(L, index);
+	if (std::isnan(v) && std::isinf(v))
+		throw LuaError("Invalid float value (NaN or infinity)");
 
-	return (float)luaL_checknumber(L, index);
+	return static_cast<float>(v);
 }
 
 template <>
 v2s16 LuaHelper::readParam(lua_State *L, int index)
 {
-	v2s16 p;
-	CHECK_POS_TAB(index);
-	lua_getfield(L, index, "x");
-	CHECK_POS_COORD("x");
-	p.X = readParam<s16>(L, -1);
-	lua_pop(L, 1);
-	lua_getfield(L, index, "y");
-	CHECK_POS_COORD("y");
-	p.Y = readParam<s16>(L, -1);
-	lua_pop(L, 1);
-	return p;
+	return read_v2s16(L, index);
 }
 
 template <>
 v2f LuaHelper::readParam(lua_State *L, int index)
 {
-	v2f p;
-	CHECK_POS_TAB(index);
-	lua_getfield(L, index, "x");
-	CHECK_POS_COORD("x");
-	p.X = readParam<float>(L, -1);
-	lua_pop(L, 1);
-	lua_getfield(L, index, "y");
-	CHECK_POS_COORD("y");
-	p.Y = readParam<float>(L, -1);
-	lua_pop(L, 1);
-	return p;
+	return check_v2f(L, index);
 }
 
 template <>
 v3f LuaHelper::readParam(lua_State *L, int index)
 {
-	v3f p;
-	CHECK_POS_TAB(index);
-	lua_getfield(L, index, "x");
-	CHECK_POS_COORD("x");
-	p.X = readParam<float>(L, -1);
-	lua_pop(L, 1);
-	lua_getfield(L, index, "y");
-	CHECK_POS_COORD("y");
-	p.Y = readParam<float>(L, -1);
-	lua_pop(L, 1);
-	lua_getfield(L, index, "z");
-	CHECK_POS_COORD("z");
-	p.Z = readParam<float>(L, -1);
-	lua_pop(L, 1);
-	return p;
+	return check_v3f(L, index);
 }
 
 template <>
diff --git a/src/script/common/helper.h b/src/script/common/helper.h
index 6491e73cf..fc462b6ef 100644
--- a/src/script/common/helper.h
+++ b/src/script/common/helper.h
@@ -21,14 +21,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 extern "C" {
 #include <lua.h>
-#include <lauxlib.h>
 }
 
 class LuaHelper
 {
 protected:
-	static bool isNaN(lua_State *L, int idx);
-
 	/**
 	 * Read a value using a template type T from Lua State L and index
 	 *