Add a tree printer for gdscript.

Author: fire

modules/gdscript/doc_classes/GDScript.xml

@@ -29,5 +29,11 @@
 				[/codeblock]
 			</description>
 		</method>
+		<method name="print_tree">
+			<return type="int" enum="Error" />
+			<description>
+				Parses the script and prints its syntax tree to the standard output. This method is mostly useful for debugging the GDScript parser and compiler. Returns [constant OK] on success or an error code if parsing fails.
+			</description>
+		</method>
 	</methods>
 </class>

modules/gdscript/gdscript.cpp

@@ -1016,6 +1016,7 @@ void GDScript::_bind_methods() {
 	ClassDB::bind_vararg_method(METHOD_FLAGS_DEFAULT, "new", &GDScript::_new, MethodInfo("new"));
 
 	ClassDB::bind_method(D_METHOD("get_as_byte_code"), &GDScript::get_as_byte_code);
+	ClassDB::bind_method(D_METHOD("print_tree"), &GDScript::print_tree);
 }
 
 Vector<uint8_t> GDScript::get_as_byte_code() const {
@@ -2381,3 +2382,20 @@ void ResourceFormatSaverGDScript::get_recognized_extensions(const RES &p_resourc
 bool ResourceFormatSaverGDScript::recognize(const RES &p_resource) const {
 	return Object::cast_to<GDScript>(*p_resource) != nullptr;
 }
+
+Error GDScript::print_tree() {
+	GDScriptParser parser;
+	Error err = parser.parse(source, path, false);
+	if (err) {
+		if (EngineDebugger::is_active()) {
+			GDScriptLanguage::get_singleton()->debug_break_parse(_get_debug_path(), parser.get_errors().front()->get().line, "Parser Error: " + parser.get_errors().front()->get().message);
+		}
+		_err_print_error("GDScript::reload", path.is_empty() ? "built-in" : (const char *)path.utf8().get_data(), parser.get_errors().front()->get().line, ("Parse Error: " + parser.get_errors().front()->get().message).utf8().get_data(), false, ERR_HANDLER_SCRIPT);
+		ERR_FAIL_V(ERR_PARSE_ERROR);
+	}
+#ifdef TOOLS_ENABLED
+	GDScriptParser::TreePrinter printer;
+	printer.print_tree(parser);
+#endif
+	return err;
+}

modules/gdscript/gdscript.h

@@ -172,6 +172,7 @@ class GDScript : public Script {
 	static void _bind_methods();
 
 public:
+	virtual Error print_tree();
 	virtual bool is_valid() const override { return valid; }
 
 	bool inherits_script(const Ref<Script> &p_script) const override;