Merge pull request #114 from gilzoide/feature/get-set-metatable

Add support for getting and setting metatable from GDScript

Author: gilzoide

CHANGELOG.md

@@ -2,6 +2,7 @@
 ## [Unreleased](https://github.com/gilzoide/lua-gdextension/compare/0.4.0...HEAD)
 ### Added
 - Support for Linux arm64
+- `LuaTable.get_metatable` and `LuaTable.set_metatable` methods
 
 
 ## [0.4.0](https://github.com/gilzoide/lua-gdextension/releases/tag/0.4.0)

doc_classes/LuaTable.xml

@@ -38,6 +38,13 @@
 				[/codeblocks]
 			</description>
 		</method>
+		<method name="get_metatable" qualifiers="const">
+			<return type="LuaTable" />
+			<description>
+				Returns this table's metatable.
+				See [url]https://www.lua.org/manual/5.4/manual.html#2.4[/url]
+			</description>
+		</method>
 		<method name="length" qualifiers="const">
 			<return type="int" />
 			<description>
@@ -101,6 +108,14 @@
 				[/codeblocks]
 			</description>
 		</method>
+		<method name="set_metatable">
+			<return type="void" />
+			<param index="0" name="metatable" type="LuaTable" />
+			<description>
+				Set a new metatable for this table.
+				See [url]https://www.lua.org/manual/5.4/manual.html#2.4[/url]
+			</description>
+		</method>
 		<method name="to_array" qualifiers="const">
 			<return type="Array" />
 			<description>

src/LuaTable.cpp

@@ -108,6 +108,19 @@ Array LuaTable::to_array() const {
 	return luagdextension::to_array(lua_object);
 }
 
+Ref<LuaTable> LuaTable::get_metatable() const {
+	if (sol::optional<sol::table> metatable = lua_object[sol::metatable_key]) {
+		return LuaObject::wrap_object<LuaTable>(*metatable);
+	}
+	else {
+		return nullptr;
+	}
+}
+
+void LuaTable::set_metatable(LuaTable *metatable) {
+	lua_object[sol::metatable_key] = metatable ? metatable->get_table() : sol::nil;
+}
+
 bool LuaTable::_iter_init(const Variant& iter) const {
 	StackTopChecker topcheck(lua_object.lua_state());
 	lua_State *L = lua_object.lua_state();
@@ -172,6 +185,9 @@ void LuaTable::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("to_dictionary"), &LuaTable::to_dictionary);
 	ClassDB::bind_method(D_METHOD("to_array"), &LuaTable::to_array);
 
+	ClassDB::bind_method(D_METHOD("get_metatable"), &LuaTable::get_metatable);
+	ClassDB::bind_method(D_METHOD("set_metatable", "metatable"), &LuaTable::set_metatable);
+
 	ClassDB::bind_method(D_METHOD("_iter_init", "iter"), &LuaTable::_iter_init);
 	ClassDB::bind_method(D_METHOD("_iter_next", "iter"), &LuaTable::_iter_next);
 	ClassDB::bind_method(D_METHOD("_iter_get", "iter"), &LuaTable::_iter_get);

src/LuaTable.hpp

@@ -53,6 +53,9 @@ class LuaTable : public LuaObjectSubclass<sol::table> {
 	Dictionary to_dictionary() const;
 	Array to_array() const;
 
+	Ref<LuaTable> get_metatable() const;
+	void set_metatable(LuaTable *metatable);
+
 	bool _iter_init(const Variant& iter) const;
 	bool _iter_next(const Variant& iter) const;
 	Variant _iter_get(const Variant& iter) const;

test/gdscript_tests/LuaTable.gd

@@ -111,3 +111,19 @@ func test_dont_unpack_other_state() -> bool:
 	var t_type = other_state.do_string("return type(t)")
 	assert(t_type == "userdata", "Table should remain as Variant when passed to another LuaState")
 	return true
+
+
+func test_setgetmetatable() -> bool:
+	var table = lua_state.create_table()
+	assert(table.get_metatable() == null)
+	assert(table.get_metatable() == lua_state.globals.getmetatable.invoke(table))
+
+	var metatable = lua_state.create_table()
+	table.set_metatable(metatable)
+	assert(table.get_metatable() == metatable)
+	assert(table.get_metatable() == lua_state.globals.getmetatable.invoke(table))
+
+	table.set_metatable(null)
+	assert(table.get_metatable() == null)
+	assert(table.get_metatable() == lua_state.globals.getmetatable.invoke(table))
+	return true